fix: suppress tar leading slash warnings

Replace the Tart-based prototype with a runner-oriented macOS VM
executor backed by runner-executor-macos and Apple Virtualization.

Assisted-by: Codet:MODEL_VERSION

README.md

@@ -201,10 +201,10 @@ A label is written as:
 | Part | Meaning |
 | --- | --- |
 | `name` | The name a workflow refers to in `runs-on`, e.g. `ubuntu-latest`. |
-| `schema` | Either `docker` or `host`. Defaults to `host` when omitted. |
-| `args` | Only used by the `docker` schema: the image to run the job in. |
+| `schema` | Either `docker`, `host`, or `macos-vm`. Defaults to `host` when omitted. |
+| `args` | Used by `docker` for the image, and by `macos-vm` for the source VM. |
 
-Two schemas are supported:
+Three schemas are supported:
 
 - **`docker://<image>`** — the job runs inside a container created from `<image>`:
 
@@ -218,15 +218,21 @@ Two schemas are supported:
   macos:host
   ```
 
+- **`macos-vm://<source-vm>`** — the job runs inside an ephemeral macOS VM created by `runner-executor-macos`. The VM image must include the runner guest agent. Service containers are not supported with this schema. See `docs/macos-vm-executor.md` for configuration, integration testing, and cleanup details:
+
+  ```text
+  macos-latest:macos-vm://ghcr.io/cirruslabs/macos-sonoma-base:latest
+  ```
+
 So with the labels
 
 ```text
-ubuntu-latest:docker://docker.gitea.com/runner-images:ubuntu-latest,macos:host
+ubuntu-latest:docker://docker.gitea.com/runner-images:ubuntu-latest,macos:host,macos-latest:macos-vm://ghcr.io/cirruslabs/macos-sonoma-base:latest
 ```
 
-a workflow with `runs-on: ubuntu-latest` is executed in the `runner-images:ubuntu-latest` container, and one with `runs-on: macos` is executed directly on the host.
+a workflow with `runs-on: ubuntu-latest` is executed in the `runner-images:ubuntu-latest` container, one with `runs-on: macos` is executed directly on the host, and one with `runs-on: macos-latest` is executed in the macOS VM.
 
-Names may themselves contain a colon (for example `pool:e57e18d4-10d4-406f-93bf-60f127221bdd`); only `host` and `docker` are treated as schemas.
+Names may themselves contain a colon (for example `pool:e57e18d4-10d4-406f-93bf-60f127221bdd`); only `host`, `docker`, and `macos-vm` are treated as schemas.
 
 If a job's `runs-on` matches none of the runner's labels, or sets no `runs-on` at all, it still runs: in `runner.default_image` where docker is available, on the host where it is not. Images maintained for this purpose are listed at [gitea/runner-images](https://gitea.com/gitea/runner-images).
 

act/container/macos_vm_cleanup.go

@@ -0,0 +1,73 @@
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package container
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"os/exec"
+	"strings"
+	"time"
+)
+
+type macOSVM struct {
+	Name       string `json:"name"`
+	State      string `json:"state"`
+	Running    bool   `json:"running"`
+	AccessedAt string `json:"accessed_at"`
+}
+
+// CleanupOrphanMacOSVMs deletes local macOS VMs left behind by this runner that
+// have not been accessed since cutoff.
+func CleanupOrphanMacOSVMs(ctx context.Context, executorPath, uuid string, cutoff time.Time) error {
+	if uuid == "" {
+		return nil
+	}
+
+	output, err := exec.CommandContext(ctx, executorPath, "list", "--format", "json").Output()
+	if err != nil {
+		return fmt.Errorf("list macOS VMs: %w", err)
+	}
+
+	var vms []macOSVM
+	if err := json.Unmarshal(output, &vms); err != nil {
+		return fmt.Errorf("parse macOS VM list: %w", err)
+	}
+
+	var errs []error
+	for _, name := range macOSVMsToDelete(vms, uuid, cutoff) {
+		if err := exec.CommandContext(ctx, executorPath, "destroy", name).Run(); err != nil {
+			errs = append(errs, fmt.Errorf("destroy macOS VM %s: %w", name, err))
+		}
+	}
+	return errors.Join(errs...)
+}
+
+func macOSVMsToDelete(vms []macOSVM, uuid string, cutoff time.Time) []string {
+	prefix := "GITEA-MACOS-VM-" + uuid + "-"
+	var stale []string
+	for _, vm := range vms {
+		if vm.Running || !strings.HasPrefix(vm.Name, prefix) {
+			continue
+		}
+		accessed, err := parseMacOSVMTime(vm.AccessedAt)
+		if err != nil || accessed.After(cutoff) {
+			continue
+		}
+		stale = append(stale, vm.Name)
+	}
+	return stale
+}
+
+func parseMacOSVMTime(raw string) (time.Time, error) {
+	if raw == "" {
+		return time.Time{}, errors.New("empty access time")
+	}
+	if parsed, err := time.Parse(time.RFC3339Nano, raw); err == nil {
+		return parsed, nil
+	}
+	return time.Parse(time.RFC3339, raw)
+}

act/container/macos_vm_cleanup_test.go

@@ -0,0 +1,37 @@
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package container
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestMacOSVMsToDelete(t *testing.T) {
+	cutoff := time.Date(2026, 9, 5, 10, 0, 0, 0, time.UTC)
+	vms := []macOSVM{
+		{Name: "GITEA-MACOS-VM-runner-1-stale", AccessedAt: "2026-09-04T10:00:00Z"},
+		{Name: "GITEA-MACOS-VM-runner-1-running", AccessedAt: "2026-09-04T10:00:00Z", Running: true},
+		{Name: "GITEA-MACOS-VM-runner-1-fresh", AccessedAt: "2026-09-05T11:00:00Z"},
+		{Name: "GITEA-MACOS-VM-runner-2-stale", AccessedAt: "2026-09-04T10:00:00Z"},
+	}
+
+	assert.Equal(t, []string{"GITEA-MACOS-VM-runner-1-stale"}, macOSVMsToDelete(vms, "runner-1", cutoff))
+}
+
+func TestParseMacOSVMTime(t *testing.T) {
+	parsed, err := parseMacOSVMTime("2026-09-05T10:00:00Z")
+	require.NoError(t, err)
+	assert.Equal(t, time.Date(2026, 9, 5, 10, 0, 0, 0, time.UTC), parsed)
+
+	parsed, err = parseMacOSVMTime("2026-09-05T10:00:00.123456789Z")
+	require.NoError(t, err)
+	assert.Equal(t, time.Date(2026, 9, 5, 10, 0, 0, 123456789, time.UTC), parsed)
+
+	_, err = parseMacOSVMTime("")
+	require.Error(t, err)
+}

act/container/macos_vm_environment.go

@@ -0,0 +1,450 @@
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package container
+
+import (
+	"archive/tar"
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"maps"
+	"os/exec"
+	"path"
+	"path/filepath"
+	"runtime"
+	"slices"
+	"strconv"
+	"strings"
+	"time"
+
+	"gitea.com/gitea/runner/act/common"
+	"gitea.com/gitea/runner/act/filecollector"
+
+	"github.com/go-git/go-billy/v5/helper/polyfill"
+	"github.com/go-git/go-billy/v5/osfs"
+	"github.com/go-git/go-git/v5/plumbing/format/gitignore"
+)
+
+const (
+	defaultMacOSVMBootTimeout = 5 * time.Minute
+	macOSVMReadyPollInterval  = 500 * time.Millisecond
+	macOSVMStopWaitTimeout    = 10 * time.Second
+)
+
+// MacOSVMEnvironment runs workflow steps in an ephemeral macOS VM.
+type MacOSVMEnvironment struct {
+	Path         string // guest scratch directory
+	TmpDir       string // guest temp directory
+	ToolCache    string // guest tool cache directory
+	Workdir      string // host-side workspace path
+	GuestWorkdir string // guest-side workspace path
+	ActPath      string // guest act directory
+
+	Image        string
+	VMName       string
+	ExecutorPath string
+	CPU          int
+	Memory       int
+	BootTimeout  time.Duration
+
+	Stdout io.Writer
+	Stderr io.Writer
+
+	executorPath string
+	running      bool
+	runCmd       *exec.Cmd
+	runDone      chan struct{}
+	runErr       error
+}
+
+// MacOSVMEnvironmentInput is the input for NewMacOSVMEnvironment.
+type MacOSVMEnvironmentInput struct {
+	Path         string
+	TmpDir       string
+	ToolCache    string
+	Workdir      string
+	GuestWorkdir string
+	ActPath      string
+	Image        string
+	VMName       string
+	ExecutorPath string
+	CPU          int
+	Memory       int
+	BootTimeout  time.Duration
+	Stdout       io.Writer
+	Stderr       io.Writer
+}
+
+func NewMacOSVMEnvironment(input MacOSVMEnvironmentInput) (*MacOSVMEnvironment, error) {
+	if input.Image == "" {
+		return nil, errors.New("macOS VM image is required")
+	}
+	if input.VMName == "" {
+		return nil, errors.New("macOS VM name is required")
+	}
+	if input.BootTimeout <= 0 {
+		input.BootTimeout = defaultMacOSVMBootTimeout
+	}
+	if input.ExecutorPath == "" {
+		input.ExecutorPath = "runner-executor-macos"
+	}
+	return &MacOSVMEnvironment{
+		Path:         input.Path,
+		TmpDir:       input.TmpDir,
+		ToolCache:    input.ToolCache,
+		Workdir:      input.Workdir,
+		GuestWorkdir: input.GuestWorkdir,
+		ActPath:      input.ActPath,
+		Image:        input.Image,
+		VMName:       input.VMName,
+		ExecutorPath: input.ExecutorPath,
+		CPU:          input.CPU,
+		Memory:       input.Memory,
+		BootTimeout:  input.BootTimeout,
+		Stdout:       input.Stdout,
+		Stderr:       input.Stderr,
+		executorPath: input.ExecutorPath,
+	}, nil
+}
+
+var _ ExecutionsEnvironment = &MacOSVMEnvironment{}
+
+func (e *MacOSVMEnvironment) Create(_, _ []string) common.Executor {
+	return func(ctx context.Context) error {
+		if common.Dryrun(ctx) {
+			return nil
+		}
+		// A previous run can leave the deterministic job VM behind. Destroy it first.
+		_ = e.runExecutor(ctx, nil, io.Discard, io.Discard, "destroy", e.VMName)
+
+		args := []string{"provision", e.Image, e.VMName}
+		if e.CPU > 0 {
+			args = append(args, "--cpu", strconv.Itoa(e.CPU))
+		}
+		if e.Memory > 0 {
+			args = append(args, "--memory", strconv.Itoa(e.Memory))
+		}
+		return e.runExecutor(ctx, nil, e.Stdout, e.Stderr, args...)
+	}
+}
+
+func (e *MacOSVMEnvironment) Copy(destPath string, files ...*FileEntry) common.Executor {
+	return func(ctx context.Context) error {
+		if common.Dryrun(ctx) {
+			return nil
+		}
+		for _, file := range files {
+			dest := path.Join(destPath, file.Name)
+			script := `mkdir -p "$1" && cat > "$2" && chmod "$3" "$2"`
+			mode := file.Mode
+			if mode == 0 {
+				mode = 0o644
+			}
+			args := []string{"exec", "--stdin", e.VMName, "/bin/sh", "-c", script, "sh", path.Dir(dest), dest, strconv.FormatInt(mode, 8)}
+			if err := e.runExecutor(ctx, strings.NewReader(file.Body), e.Stdout, e.Stderr, args...); err != nil {
+				return err
+			}
+		}
+		return nil
+	}
+}
+
+func (e *MacOSVMEnvironment) CopyDir(destPath, srcPath string, useGitIgnore bool) common.Executor {
+	return func(ctx context.Context) error {
+		if common.Dryrun(ctx) {
+			return nil
+		}
+		pipeReader, pipeWriter := io.Pipe()
+		writeDone := make(chan error, 1)
+		go func() {
+			err := e.writeTar(ctx, pipeWriter, srcPath, useGitIgnore)
+			_ = pipeWriter.CloseWithError(err)
+			writeDone <- err
+		}()
+
+		script := `export COPYFILE_DISABLE=1; mkdir -p "$1" && /usr/bin/tar -xf - -C "$1"`
+		cmdErr := e.runExecutor(ctx, pipeReader, e.Stdout, e.Stderr, "exec", "--stdin", e.VMName, "/bin/sh", "-c", script, "sh", destPath)
+		_ = pipeReader.Close()
+		writeErr := <-writeDone
+		return errors.Join(cmdErr, writeErr)
+	}
+}
+
+func (e *MacOSVMEnvironment) writeTar(ctx context.Context, writer io.Writer, srcPath string, useGitIgnore bool) error {
+	tarWriter := tar.NewWriter(writer)
+	defer tarWriter.Close()
+
+	srcPrefix := filepath.Dir(srcPath)
+	if !strings.HasSuffix(srcPrefix, string(filepath.Separator)) {
+		srcPrefix += string(filepath.Separator)
+	}
+
+	var ignorer gitignore.Matcher
+	if useGitIgnore {
+		patterns, err := gitignore.ReadPatterns(polyfill.New(osfs.New(srcPath)), nil)
+		if err != nil {
+			common.Logger(ctx).Debugf("Error loading .gitignore: %v", err)
+		}
+		ignorer = gitignore.NewMatcher(patterns)
+	}
+
+	collector := &filecollector.FileCollector{
+		Ignorer:   ignorer,
+		SrcPath:   srcPath,
+		SrcPrefix: srcPrefix,
+		Handler:   &filecollector.TarCollector{TarWriter: tarWriter},
+	}
+	return filepath.Walk(srcPath, collector.CollectFiles(ctx, []string{}))
+}
+
+func (e *MacOSVMEnvironment) GetContainerArchive(ctx context.Context, srcPath string) (io.ReadCloser, error) {
+	if common.Dryrun(ctx) {
+		return nil, errors.New("DRYRUN is not supported in GetContainerArchive")
+	}
+	cmd := exec.CommandContext(ctx, e.executorPath, "exec", e.VMName, "/usr/bin/env", "COPYFILE_DISABLE=1", "/usr/bin/tar", "-cf", "-", "-C", "/", strings.TrimPrefix(srcPath, "/"))
+	stdout, err := cmd.StdoutPipe()
+	if err != nil {
+		return nil, err
+	}
+	cmd.Stderr = e.Stderr
+	if err := cmd.Start(); err != nil {
+		return nil, err
+	}
+	return &macOSVMArchiveReader{ReadCloser: stdout, cmd: cmd}, nil
+}
+
+type macOSVMArchiveReader struct {
+	io.ReadCloser
+	cmd *exec.Cmd
+}
+
+func (r *macOSVMArchiveReader) Close() error {
+	closeErr := r.ReadCloser.Close()
+	return errors.Join(closeErr, r.cmd.Wait())
+}
+
+func (e *MacOSVMEnvironment) Inspect(ctx context.Context) (*Info, error) {
+	if common.Dryrun(ctx) {
+		return &Info{Health: HealthNone, Ports: map[string]string{}}, nil
+	}
+	state := "exited"
+	if e.running {
+		state = StateRunning
+	}
+	return &Info{ID: e.VMName, State: state, Health: HealthNone, Ports: map[string]string{}}, nil
+}
+
+func (e *MacOSVMEnvironment) DumpLogs(context.Context) error {
+	return nil
+}
+
+func (e *MacOSVMEnvironment) Pull(forcePull bool) common.Executor {
+	return func(ctx context.Context) error {
+		if common.Dryrun(ctx) {
+			return nil
+		}
+		return nil
+	}
+}
+
+func (e *MacOSVMEnvironment) Start(bool) common.Executor {
+	return func(ctx context.Context) error {
+		if common.Dryrun(ctx) {
+			return nil
+		}
+		cmd := exec.Command(e.executorPath, "start", "--no-graphics", e.VMName)
+		cmd.Stdout = e.Stdout
+		cmd.Stderr = e.Stderr
+		if err := cmd.Start(); err != nil {
+			return err
+		}
+		e.runCmd = cmd
+		e.runDone = make(chan struct{})
+		go func() {
+			e.runErr = cmd.Wait()
+			close(e.runDone)
+		}()
+		e.running = true
+		return e.waitReady(ctx)
+	}
+}
+
+func (e *MacOSVMEnvironment) waitReady(ctx context.Context) error {
+	ctx, cancel := context.WithTimeout(ctx, e.BootTimeout)
+	defer cancel()
+
+	var lastErr error
+	for {
+		if err := e.runExecutor(ctx, nil, io.Discard, io.Discard, "exec", e.VMName, "/usr/bin/true"); err == nil {
+			return nil
+		} else {
+			lastErr = err
+		}
+
+		select {
+		case <-ctx.Done():
+			return fmt.Errorf("macOS VM %s did not become ready: %w", e.VMName, lastErr)
+		case <-e.runDone:
+			if e.runErr != nil {
+				return fmt.Errorf("macOS VM start exited before the VM became ready: %w", e.runErr)
+			}
+			return errors.New("macOS VM start exited before the VM became ready")
+		case <-time.After(macOSVMReadyPollInterval):
+		}
+	}
+}
+
+func (e *MacOSVMEnvironment) Exec(command []string, env map[string]string, _, workdir string) common.Executor {
+	return func(ctx context.Context) error {
+		if common.Dryrun(ctx) {
+			return nil
+		}
+		err := e.runExecutor(ctx, nil, e.Stdout, e.Stderr, macOSVMExecArgs(e.VMName, command, env, e.resolveWorkdir(workdir))...)
+		if exitErr, ok := errors.AsType[*exec.ExitError](err); ok {
+			return ExitCodeError(exitErr.ExitCode())
+		}
+		return err
+	}
+}
+
+func macOSVMExecArgs(vmName string, command []string, env map[string]string, workdir string) []string {
+	args := []string{"exec", vmName, "/usr/bin/env"}
+	for _, key := range slices.Sorted(maps.Keys(env)) {
+		args = append(args, key+"="+env[key])
+	}
+	args = append(args, "/bin/sh", "-c", `cd "$1" && shift && exec "$@"`, "sh", workdir)
+	return append(args, command...)
+}
+
+func (e *MacOSVMEnvironment) resolveWorkdir(workdir string) string {
+	switch {
+	case workdir == "":
+		return e.GuestWorkdir
+	case strings.HasPrefix(workdir, "/"):
+		return workdir
+	default:
+		return path.Join(e.GuestWorkdir, workdir)
+	}
+}
+
+func (e *MacOSVMEnvironment) UpdateFromEnv(srcPath string, env *map[string]string) common.Executor {
+	return parseEnvFile(e, srcPath, env)
+}
+
+func (e *MacOSVMEnvironment) UpdateFromImageEnv(*map[string]string) common.Executor {
+	return func(context.Context) error {
+		return nil
+	}
+}
+
+func (e *MacOSVMEnvironment) Remove() common.Executor {
+	return func(ctx context.Context) error {
+		if common.Dryrun(ctx) {
+			return nil
+		}
+		cleanCtx, cancel := context.WithTimeout(context.WithoutCancel(ctx), time.Minute)
+		defer cancel()
+
+		if e.runCmd != nil && e.runDone != nil {
+			select {
+			case <-e.runDone:
+			default:
+				if err := e.runExecutor(cleanCtx, nil, e.Stdout, e.Stderr, "stop", e.VMName, "--timeout", "20"); err != nil {
+					common.Logger(ctx).Debugf("macOS VM stop failed for VM %s: %v", e.VMName, err)
+				}
+				select {
+				case <-e.runDone:
+				case <-time.After(macOSVMStopWaitTimeout):
+					if e.runCmd.Process != nil {
+						_ = e.runCmd.Process.Kill()
+					}
+					common.Logger(ctx).Warnf("timed out waiting for macOS VM start to exit for VM %s", e.VMName)
+				}
+			}
+		}
+		e.running = false
+		if err := e.runExecutor(cleanCtx, nil, e.Stdout, e.Stderr, "destroy", e.VMName); err != nil {
+			common.Logger(ctx).Warnf("failed to destroy macOS VM %s: %v", e.VMName, err)
+		}
+		return nil
+	}
+}
+
+func (e *MacOSVMEnvironment) Close() common.Executor {
+	return func(ctx context.Context) error {
+		if common.Dryrun(ctx) {
+			return nil
+		}
+		if e.runCmd != nil && e.runCmd.Process != nil {
+			_ = e.runCmd.Process.Kill()
+		}
+		e.runCmd = nil
+		return nil
+	}
+}
+
+func (e *MacOSVMEnvironment) ReplaceLogWriter(stdout, stderr io.Writer) (io.Writer, io.Writer) {
+	oldOut := e.Stdout
+	oldErr := e.Stderr
+	e.Stdout = stdout
+	e.Stderr = stderr
+	return oldOut, oldErr
+}
+
+func (e *MacOSVMEnvironment) ToContainerPath(hostPath string) string {
+	if filepath.Clean(hostPath) == filepath.Clean(e.Workdir) {
+		return e.GuestWorkdir
+	}
+	if rel, err := filepath.Rel(e.Workdir, hostPath); err == nil && rel != "." && rel != ".." && !strings.HasPrefix(rel, ".."+string(filepath.Separator)) {
+		return path.Join(e.GuestWorkdir, filepath.ToSlash(rel))
+	}
+	return filepath.ToSlash(hostPath)
+}
+
+func (e *MacOSVMEnvironment) GetActPath() string {
+	return e.ActPath
+}
+
+func (*MacOSVMEnvironment) GetPathVariableName() string {
+	return "PATH"
+}
+
+func (*MacOSVMEnvironment) DefaultPathVariable() string {
+	return "/usr/local/bin:/opt/homebrew/bin:/usr/bin:/bin:/usr/sbin:/sbin"
+}
+
+func (*MacOSVMEnvironment) JoinPathVariable(paths ...string) string {
+	return strings.Join(paths, ":")
+}
+
+func (e *MacOSVMEnvironment) GetRunnerContext(context.Context) map[string]any {
+	return map[string]any{
+		"os":         "macOS",
+		"arch":       goArchToActionArch(runtime.GOARCH),
+		"temp":       e.TmpDir,
+		"tool_cache": e.ToolCache,
+	}
+}
+
+func (*MacOSVMEnvironment) IsEnvironmentCaseInsensitive() bool {
+	return false
+}
+
+func (e *MacOSVMEnvironment) runExecutor(ctx context.Context, stdin io.Reader, stdout, stderr io.Writer, args ...string) error {
+	if stdout == nil {
+		stdout = e.Stdout
+	}
+	if stderr == nil {
+		stderr = e.Stderr
+	}
+	cmd := exec.CommandContext(ctx, e.executorPath, args...)
+	cmd.Stdin = stdin
+	cmd.Stdout = stdout
+	cmd.Stderr = stderr
+	if err := cmd.Run(); err != nil {
+		return fmt.Errorf("macOS VM executor %s: %w", args[0], err)
+	}
+	return nil
+}

act/container/macos_vm_environment_integration_test.go

@@ -0,0 +1,97 @@
+//go:build macos_vm_integration
+
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package container
+
+import (
+	"archive/tar"
+	"bytes"
+	"context"
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+	"runtime"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestMacOSVMEnvironmentIntegration(t *testing.T) {
+	if runtime.GOOS != "darwin" {
+		t.Skip("macOS VMs run on macOS")
+	}
+	if _, err := exec.LookPath("runner-executor-macos"); err != nil {
+		t.Skip("runner-executor-macos executable not found")
+	}
+	image := os.Getenv("MACOS_VM_TEST_IMAGE")
+	if image == "" {
+		t.Skip("set MACOS_VM_TEST_IMAGE to a macOS VM image to run this test")
+	}
+
+	ctx := context.Background()
+	vmName := fmt.Sprintf("gitea-runner-test-%d", time.Now().UnixNano())
+	base := "/Users/admin/runner"
+	if os.Getenv("RUNNER_EXECUTOR_MACOS_DEV_MODE") == "1" {
+		base = t.TempDir()
+	}
+	env, err := NewMacOSVMEnvironment(MacOSVMEnvironmentInput{
+		Path:         base + "/scratch/" + vmName,
+		TmpDir:       base + "/scratch/" + vmName + "/tmp",
+		ToolCache:    base + "/scratch/" + vmName + "/tool_cache",
+		Workdir:      t.TempDir(),
+		GuestWorkdir: base + "/workspace/" + vmName,
+		ActPath:      base + "/scratch/" + vmName + "/act",
+		Image:        image,
+		VMName:       vmName,
+		ExecutorPath: "runner-executor-macos",
+		BootTimeout:  10 * time.Minute,
+		Stdout:       io.Discard,
+		Stderr:       io.Discard,
+	})
+	require.NoError(t, err)
+	t.Cleanup(func() {
+		_ = env.Remove()(context.Background())
+	})
+
+	require.NoError(t, env.Create(nil, nil)(ctx))
+	require.NoError(t, env.Start(false)(ctx))
+	if os.Getenv("RUNNER_EXECUTOR_MACOS_DEV_MODE") == "1" {
+		require.NoError(t, os.MkdirAll(env.GuestWorkdir, 0o755))
+	}
+	require.NoError(t, env.Exec([]string{"/bin/mkdir", "-p", env.GuestWorkdir}, nil, "", "/")(ctx))
+
+	require.NoError(t, env.Copy("/tmp", &FileEntry{
+		Name: "gitea-runner-macos.txt",
+		Mode: 0o644,
+		Body: "hello from macos-vm",
+	})(ctx))
+
+	archive, err := env.GetContainerArchive(ctx, "/tmp/gitea-runner-macos.txt")
+	require.NoError(t, err)
+	body := readFirstTarFile(t, archive)
+	require.NoError(t, archive.Close())
+	require.Equal(t, "hello from macos-vm", body)
+
+	var output bytes.Buffer
+	oldOut, oldErr := env.ReplaceLogWriter(&output, &output)
+	defer env.ReplaceLogWriter(oldOut, oldErr)
+	require.NoError(t, env.Exec([]string{"/usr/bin/uname", "-s"}, nil, "", "")(ctx))
+	require.Contains(t, output.String(), "Darwin")
+
+	require.NoError(t, env.Remove()(ctx))
+}
+
+func readFirstTarFile(t *testing.T, archive io.Reader) string {
+	t.Helper()
+	reader := tar.NewReader(archive)
+	header, err := reader.Next()
+	require.NoError(t, err)
+	require.Contains(t, header.Name, "gitea-runner-macos.txt")
+	body, err := io.ReadAll(reader)
+	require.NoError(t, err)
+	return string(body)
+}

act/container/macos_vm_environment_test.go

@@ -0,0 +1,91 @@
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package container
+
+import (
+	"context"
+	"io"
+	"runtime"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestNewMacOSVMEnvironment(t *testing.T) {
+	env, err := NewMacOSVMEnvironment(MacOSVMEnvironmentInput{
+		Image:  "ghcr.io/cirruslabs/macos-sonoma-base:latest",
+		VMName: "job-vm",
+	})
+	require.NoError(t, err)
+	assert.Equal(t, "ghcr.io/cirruslabs/macos-sonoma-base:latest", env.Image)
+	assert.Equal(t, "job-vm", env.VMName)
+	assert.Equal(t, defaultMacOSVMBootTimeout, env.BootTimeout)
+	assert.Equal(t, "runner-executor-macos", env.executorPath)
+
+	_, err = NewMacOSVMEnvironment(MacOSVMEnvironmentInput{VMName: "job-vm"})
+	require.Error(t, err)
+	_, err = NewMacOSVMEnvironment(MacOSVMEnvironmentInput{Image: "macos"})
+	require.Error(t, err)
+}
+
+func TestMacOSVMExecArgs(t *testing.T) {
+	args := macOSVMExecArgs("vm", []string{"bash", "-c", "echo hi"}, map[string]string{"B": "two", "A": "one"}, "/Users/admin/work")
+	assert.Equal(t, []string{
+		"exec", "vm", "/usr/bin/env",
+		"A=one", "B=two",
+		"/bin/sh", "-c", `cd "$1" && shift && exec "$@"`, "sh", "/Users/admin/work",
+		"bash", "-c", "echo hi",
+	}, args)
+
+	args = macOSVMExecArgs("vm", []string{"true"}, nil, "")
+	assert.Equal(t, []string{
+		"exec", "vm", "/usr/bin/env",
+		"/bin/sh", "-c", `cd "$1" && shift && exec "$@"`, "sh", "",
+		"true",
+	}, args)
+}
+
+func TestMacOSVMEnvironmentResolveWorkdir(t *testing.T) {
+	env := &MacOSVMEnvironment{GuestWorkdir: "/Users/admin/work"}
+	assert.Equal(t, "/Users/admin/work", env.resolveWorkdir(""))
+	assert.Equal(t, "/Users/admin/work/sub", env.resolveWorkdir("sub"))
+	assert.Equal(t, "/tmp", env.resolveWorkdir("/tmp"))
+}
+
+func TestMacOSVMEnvironmentToContainerPath(t *testing.T) {
+	env := &MacOSVMEnvironment{Workdir: "/workspace/owner/repo", GuestWorkdir: "/Users/admin/work/owner/repo"}
+	assert.Equal(t, "/Users/admin/work/owner/repo", env.ToContainerPath("/workspace/owner/repo"))
+	assert.Equal(t, "/Users/admin/work/owner/repo/sub", env.ToContainerPath("/workspace/owner/repo/sub"))
+	assert.Equal(t, "/elsewhere", env.ToContainerPath("/elsewhere"))
+}
+
+func TestMacOSVMEnvironmentGetRunnerContext(t *testing.T) {
+	env := &MacOSVMEnvironment{
+		TmpDir:    "/Users/admin/scratch/tmp",
+		ToolCache: "/Users/admin/scratch/tool_cache",
+	}
+	ctx := env.GetRunnerContext(context.Background())
+	assert.Equal(t, "macOS", ctx["os"])
+	assert.Equal(t, goArchToActionArch(runtime.GOARCH), ctx["arch"])
+	assert.Equal(t, "/Users/admin/scratch/tmp", ctx["temp"])
+	assert.Equal(t, "/Users/admin/scratch/tool_cache", ctx["tool_cache"])
+}
+
+func TestMacOSVMEnvironmentReplaceLogWriter(t *testing.T) {
+	oldOut := io.Discard
+	oldErr := io.Discard
+	env := &MacOSVMEnvironment{Stdout: oldOut, Stderr: oldErr}
+	newOut, newErr := env.ReplaceLogWriter(io.Discard, io.Discard)
+	assert.Equal(t, oldOut, newOut)
+	assert.Equal(t, oldErr, newErr)
+}
+
+func TestMacOSVMEnvironmentDefaultPathVariable(t *testing.T) {
+	env := &MacOSVMEnvironment{}
+	assert.Equal(t, "PATH", env.GetPathVariableName())
+	assert.Equal(t, "/usr/local/bin:/opt/homebrew/bin:/usr/bin:/bin:/usr/sbin:/sbin", env.DefaultPathVariable())
+	assert.Equal(t, "/a:/b", env.JoinPathVariable("/a", "/b"))
+	assert.False(t, env.IsEnvironmentCaseInsensitive())
+}

act/runner/action.go

@@ -32,7 +32,7 @@ type actionStep interface {
 	step
 
 	getActionModel() *model.Action
-	getCompositeRunContext(context.Context) *RunContext
+	getCompositeRunContext(context.Context) (*RunContext, error)
 	getCompositeSteps() *compositeSteps
 }
 
@@ -172,7 +172,9 @@ func runActionImpl(step actionStep, actionDir string, remoteAction *remoteAction
 
 		rc.withGithubEnv(ctx, step.getGithubContext(ctx), *step.getEnv())
 		populateEnvsFromSavedState(step.getEnv(), step, rc)
-		populateEnvsFromInput(ctx, step.getEnv(), action, rc)
+		if err := populateEnvsFromInput(ctx, step.getEnv(), action, rc); err != nil {
+			return err
+		}
 
 		actionLocation := path.Join(actionDir, actionPath)
 		actionName, containerActionDir := getContainerActionPaths(stepModel, actionLocation, rc)
@@ -352,23 +354,35 @@ func execAsDocker(ctx context.Context, step actionStep, actionName, actionDir, b
 		}
 	}
 	eval := rc.NewActionInputsExpressionEvaluator(ctx, step)
-	cmd, err := shellquote.Split(eval.Interpolate(ctx, step.getStepModel().With["args"]))
+	args, err := eval.Interpolate(ctx, step.getStepModel().With["args"])
+	if err != nil {
+		return fmt.Errorf("unable to interpolate with.args: %w", err)
+	}
+	cmd, err := shellquote.Split(args)
+	if err != nil {
+		return err
+	}
+	ee, err := evalDockerEnv(ctx, step, action)
 	if err != nil {
 		return err
 	}
-	ee := evalDockerEnv(ctx, step, action)
 	if action.Runs.Args != nil {
 		// a fresh slice, the manifest is evaluated again for every stage
 		cmd = make([]string, len(action.Runs.Args))
 		for i, v := range action.Runs.Args {
-			cmd[i] = ee.Interpolate(ctx, v)
+			if cmd[i], err = ee.Interpolate(ctx, v); err != nil {
+				return fmt.Errorf("unable to interpolate runs.args: %w", err)
+			}
 		}
 	}
 	entrypoint, err := dockerEntrypoint(ctx, step, eval, stage)
 	if err != nil {
 		return err
 	}
-	stepContainer := newStepContainer(ctx, step, image, cmd, entrypoint, rc.Config.ContainerOptions)
+	stepContainer, err := newStepContainer(ctx, step, image, cmd, entrypoint, rc.Config.ContainerOptions)
+	if err != nil {
+		return err
+	}
 	return common.NewPipelineExecutor(
 		prepImage,
 		stepContainer.Pull(forcePull),
@@ -392,7 +406,11 @@ func dockerEntrypoint(ctx context.Context, step actionStep, eval *expressionEval
 	default:
 		entrypoint = runs.Entrypoint
 		if entrypoint == "" {
-			if fields := strings.Fields(eval.Interpolate(ctx, step.getStepModel().With["entrypoint"])); len(fields) > 0 {
+			withEntrypoint, err := eval.Interpolate(ctx, step.getStepModel().With["entrypoint"])
+			if err != nil {
+				return nil, fmt.Errorf("unable to interpolate with.entrypoint: %w", err)
+			}
+			if fields := strings.Fields(withEntrypoint); len(fields) > 0 {
 				return fields, nil
 			}
 		}
@@ -405,19 +423,22 @@ func dockerEntrypoint(ctx context.Context, step actionStep, eval *expressionEval
 }
 
 // evalDockerEnv returns an evaluator bound to the environment it installed.
-func evalDockerEnv(ctx context.Context, step step, action *model.Action) *expressionEvaluator {
+func evalDockerEnv(ctx context.Context, step step, action *model.Action) (*expressionEvaluator, error) {
 	rc := step.getRunContext()
 	stepModel := step.getStepModel()
 
+	var err error
 	inputs := make(map[string]string)
 	eval := rc.NewExpressionEvaluator(ctx)
 	// Set Defaults
 	for k, input := range action.Inputs {
-		inputs[k] = eval.Interpolate(ctx, input.Default)
+		if inputs[k], err = eval.Interpolate(ctx, input.Default); err != nil {
+			return nil, fmt.Errorf("unable to interpolate the default of input %s: %w", k, err)
+		}
 	}
-	if stepModel.With != nil {
-		for k, v := range stepModel.With {
-			inputs[k] = eval.Interpolate(ctx, v)
+	for k, v := range stepModel.With {
+		if inputs[k], err = eval.Interpolate(ctx, v); err != nil {
+			return nil, fmt.Errorf("unable to interpolate with.%s: %w", k, err)
 		}
 	}
 	mergeIntoMap(step, step.getEnv(), inputs)
@@ -428,12 +449,14 @@ func evalDockerEnv(ctx context.Context, step step, action *model.Action) *expres
 
 	ee := rc.NewActionInputsExpressionEvaluator(ctx, step)
 	for k, v := range *step.getEnv() {
-		(*step.getEnv())[k] = ee.Interpolate(ctx, v)
+		if (*step.getEnv())[k], err = ee.Interpolate(ctx, v); err != nil {
+			return nil, fmt.Errorf("unable to interpolate env %s: %w", k, err)
+		}
 	}
-	return ee
+	return ee, nil
 }
 
-func newStepContainer(ctx context.Context, step step, image string, cmd, entrypoint []string, runnerOptions string) container.Container {
+func newStepContainer(ctx context.Context, step step, image string, cmd, entrypoint []string, runnerOptions string) (container.Container, error) {
 	rc := step.getRunContext()
 	logWriter := rc.commandLogWriter(ctx)
 	envList := make([]string, 0)
@@ -443,9 +466,12 @@ func newStepContainer(ctx context.Context, step step, image string, cmd, entrypo
 
 	envList = append(envList, rc.runnerEnv(ctx)...)
 
-	binds, mounts := rc.GetBindsAndMounts()
+	binds, mounts, err := rc.GetBindsAndMounts()
+	if err != nil {
+		return nil, err
+	}
 	networkMode := "container:" + rc.jobContainerName()
-	if rc.IsHostEnv(ctx) {
+	if rc.IsHostEnv() {
 		networkMode = "default"
 	}
 	return ContainerNewContainer(&container.NewContainerInput{
@@ -467,7 +493,7 @@ func newStepContainer(ctx context.Context, step step, image string, cmd, entrypo
 		AutoRemove:    true,
 		ValidVolumes:  rc.validVolumes(),
 		AllocatePTY:   rc.Config.AllocatePTY,
-	})
+	}), nil
 }
 
 func populateEnvsFromSavedState(env *map[string]string, step actionStep, rc *RunContext) {
@@ -480,15 +506,19 @@ func populateEnvsFromSavedState(env *map[string]string, step actionStep, rc *Run
 	}
 }
 
-func populateEnvsFromInput(ctx context.Context, env *map[string]string, action *model.Action, rc *RunContext) {
+func populateEnvsFromInput(ctx context.Context, env *map[string]string, action *model.Action, rc *RunContext) error {
 	eval := rc.NewExpressionEvaluator(ctx)
 	for inputID, input := range action.Inputs {
 		envKey := regexp.MustCompile("[^A-Z0-9-]").ReplaceAllString(strings.ToUpper(inputID), "_")
 		envKey = "INPUT_" + envKey
 		if _, ok := (*env)[envKey]; !ok {
-			(*env)[envKey] = eval.Interpolate(ctx, input.Default)
+			var err error
+			if (*env)[envKey], err = eval.Interpolate(ctx, input.Default); err != nil {
+				return fmt.Errorf("unable to interpolate the default of input %s: %w", inputID, err)
+			}
 		}
 	}
+	return nil
 }
 
 func getContainerActionPaths(step *model.Step, actionDir string, rc *RunContext) (string, string) {
@@ -588,11 +618,14 @@ func runPreStep(step actionStep) common.Executor {
 		actionDir, actionPath, _, containerActionDir := actionStagePaths(step)
 
 		x := action.Runs.Using
+		if !x.IsComposite() {
+			// defaults in pre steps were missing, however provided inputs are available
+			if err := populateEnvsFromInput(ctx, step.getEnv(), action, rc); err != nil {
+				return err
+			}
+		}
 		switch {
 		case x.IsNode():
-			// defaults in pre steps were missing, however provided inputs are available
-			populateEnvsFromInput(ctx, step.getEnv(), action, rc)
-
 			if err := maybeCopyToActionDir(ctx, step, actionDir, actionPath, containerActionDir); err != nil {
 				return err
 			}
@@ -605,14 +638,13 @@ func runPreStep(step actionStep) common.Executor {
 			return rc.JobContainer.Exec(containerArgs, *step.getEnv(), "", "")(ctx)
 
 		case x.IsDocker():
-			// defaults in pre steps were missing, however provided inputs are available
-			populateEnvsFromInput(ctx, step.getEnv(), action, rc)
-
 			return execDockerActionStage(ctx, step, stepStagePre)
 
 		case x.IsComposite():
 			if step.getCompositeSteps() == nil {
-				step.getCompositeRunContext(ctx)
+				if _, err := step.getCompositeRunContext(ctx); err != nil {
+					return err
+				}
 			}
 
 			if steps := step.getCompositeSteps(); steps != nil && steps.pre != nil {
@@ -621,9 +653,6 @@ func runPreStep(step actionStep) common.Executor {
 			return errors.New("missing steps in composite action")
 
 		case x == model.ActionRunsUsingGo:
-			// defaults in pre steps were missing, however provided inputs are available
-			populateEnvsFromInput(ctx, step.getEnv(), action, rc)
-
 			if err := maybeCopyToActionDir(ctx, step, actionDir, actionPath, containerActionDir); err != nil {
 				return err
 			}

act/runner/action_composite.go

@@ -7,6 +7,7 @@ package runner
 import (
 	"context"
 	"errors"
+	"fmt"
 	"regexp"
 	"slices"
 	"strconv"
@@ -17,7 +18,7 @@ import (
 	"gitea.dev/actionslib/pkg/model"
 )
 
-func evaluateCompositeInputAndEnv(ctx context.Context, parent *RunContext, step actionStep) map[string]string {
+func evaluateCompositeInputAndEnv(ctx context.Context, parent *RunContext, step actionStep) (map[string]string, error) {
 	env := make(map[string]string)
 	stepEnv := *step.getEnv()
 	for k, v := range stepEnv {
@@ -47,14 +48,17 @@ func evaluateCompositeInputAndEnv(ctx context.Context, parent *RunContext, step
 			env[envKey] = value
 		} else {
 			// defaults could contain expressions
-			env[envKey] = ee.Interpolate(ctx, input.Default)
+			var err error
+			if env[envKey], err = ee.Interpolate(ctx, input.Default); err != nil {
+				return nil, fmt.Errorf("unable to interpolate the default of input %s: %w", inputID, err)
+			}
 		}
 	}
 	gh := step.getGithubContext(ctx)
 	env["GITHUB_ACTION_REPOSITORY"] = gh.ActionRepository
 	env["GITHUB_ACTION_REF"] = gh.ActionRef
 
-	return env
+	return env, nil
 }
 
 func (rc *RunContext) setCompositeActionEnv(env map[string]string) {
@@ -66,8 +70,11 @@ func (rc *RunContext) setCompositeActionEnv(env map[string]string) {
 	}
 }
 
-func newCompositeRunContext(ctx context.Context, parent *RunContext, step actionStep, actionPath string) *RunContext {
-	env := evaluateCompositeInputAndEnv(ctx, parent, step)
+func newCompositeRunContext(ctx context.Context, parent *RunContext, step actionStep, actionPath string) (*RunContext, error) {
+	env, err := evaluateCompositeInputAndEnv(ctx, parent, step)
+	if err != nil {
+		return nil, err
+	}
 
 	// run with the global config but without secrets
 	configCopy := *parent.Config
@@ -87,20 +94,21 @@ func newCompositeRunContext(ctx context.Context, parent *RunContext, step action
 				},
 			},
 		},
-		Config:       &configCopy,
-		StepResults:  map[string]*model.StepResult{},
-		JobContainer: parent.JobContainer,
-		ActionPath:   actionPath,
-		GlobalEnv:    parent.GlobalEnv,
-		Masks:        parent.Masks,
-		ExtraPath:    parent.ExtraPath,
-		Parent:       parent,
-		EventJSON:    parent.EventJSON,
+		Config:        &configCopy,
+		StepResults:   map[string]*model.StepResult{},
+		JobContainer:  parent.JobContainer,
+		ActionPath:    actionPath,
+		GlobalEnv:     parent.GlobalEnv,
+		Masks:         parent.Masks,
+		ExtraPath:     parent.ExtraPath,
+		Parent:        parent,
+		EventJSON:     parent.EventJSON,
+		platformImage: parent.platformImage,
 	}
 	compositerc.setCompositeActionEnv(env)
 	compositerc.ExprEval = compositerc.NewExpressionEvaluator(ctx)
 
-	return compositerc
+	return compositerc, nil
 }
 
 // appendUniqueMasks appends the masks from src to dst, skipping any mask that
@@ -121,7 +129,10 @@ func execAsComposite(step actionStep) common.Executor {
 	action := step.getActionModel()
 
 	return func(ctx context.Context) error {
-		compositeRC := step.getCompositeRunContext(ctx)
+		compositeRC, err := step.getCompositeRunContext(ctx)
+		if err != nil {
+			return err
+		}
 
 		steps := step.getCompositeSteps()
 
@@ -131,14 +142,17 @@ func execAsComposite(step actionStep) common.Executor {
 
 		ctx = WithCompositeLogger(ctx, &compositeRC.Masks)
 
-		err := steps.main(ctx)
+		err = steps.main(ctx)
 
 		// Map outputs from composite RunContext to job RunContext
 		eval := compositeRC.NewExpressionEvaluator(ctx)
 		for outputName, output := range action.Outputs {
-			rc.setOutput(ctx, map[string]string{
-				"name": outputName,
-			}, eval.Interpolate(ctx, output.Value))
+			value, outputErr := eval.Interpolate(ctx, output.Value)
+			if outputErr != nil {
+				err = errors.Join(err, fmt.Errorf("unable to interpolate output %s: %w", outputName, outputErr))
+				continue
+			}
+			rc.setOutput(ctx, map[string]string{"name": outputName}, value)
 		}
 
 		// compositeRC.Masks is seeded with rc.Masks (see newCompositeRunContext)

act/runner/action_composite_test.go

@@ -19,25 +19,30 @@ func TestCompositeActionParity(t *testing.T) {
 		ctx := t.Context()
 		strategy := &model.Strategy{MaxParallel: 3}
 		parent := &RunContext{
-			Config:       &Config{},
-			Matrix:       map[string]any{"os": "linux"},
-			Run:          &model.Run{JobID: "job", Workflow: &model.Workflow{Name: "workflow", Jobs: map[string]*model.Job{"job": {Strategy: strategy}}}},
-			JobContainer: &jobContainerMock{},
+			Config:        &Config{},
+			Matrix:        map[string]any{"os": "linux"},
+			Run:           &model.Run{JobID: "job", Workflow: &model.Workflow{Name: "workflow", Jobs: map[string]*model.Job{"job": {Strategy: strategy}}}},
+			JobContainer:  &jobContainerMock{},
+			platformImage: "-self-hosted",
 		}
-		composite := newCompositeRunContext(ctx, parent, &stepActionRemote{
+		composite, err := newCompositeRunContext(ctx, parent, &stepActionRemote{
 			Step:       &model.Step{With: map[string]string{"SHARED": "outer"}},
 			RunContext: parent,
 			action:     &model.Action{Inputs: map[string]model.Input{"shared": {Default: "outer-default"}}},
 			env:        map[string]string{"INPUT_SHARED": "outer"},
 		}, "/action")
+		require.NoError(t, err)
 
 		assert.Same(t, strategy, composite.Run.Job().Strategy)
-		assert.Equal(t, "linux|3|outer", composite.NewExpressionEvaluator(ctx).Interpolate(ctx,
-			"${{ matrix.os }}|${{ strategy.max-parallel }}|${{ inputs.shared }}"))
+		assert.True(t, composite.IsHostEnv())
+		interpolated, err := composite.NewExpressionEvaluator(ctx).Interpolate(ctx,
+			"${{ matrix.os }}|${{ strategy.max-parallel }}|${{ inputs.shared }}")
+		require.NoError(t, err)
+		assert.Equal(t, "linux|3|outer", interpolated)
 		assert.NotContains(t, composite.Env, "INPUT_SHARED")
 
 		nestedEnv := composite.GetEnv()
-		populateEnvsFromInput(ctx, &nestedEnv, &model.Action{Inputs: map[string]model.Input{"shared": {Default: "inner-default"}}}, composite)
+		require.NoError(t, populateEnvsFromInput(ctx, &nestedEnv, &model.Action{Inputs: map[string]model.Input{"shared": {Default: "inner-default"}}}, composite))
 		assert.Equal(t, "inner-default", nestedEnv["INPUT_SHARED"])
 	})
 

act/runner/action_test.go

@@ -316,7 +316,7 @@ func TestNewStepContainerDoesNotUseDockerSecrets(t *testing.T) {
 	step.On("getStepModel").Return(&model.Step{ID: "action"})
 	step.On("getEnv").Return(&env)
 
-	_ = newStepContainer(ctx, step, "registry.example.com/action:tag", nil, nil, "")
+	_, _ = newStepContainer(ctx, step, "registry.example.com/action:tag", nil, nil, "")
 
 	// DOCKER_USERNAME/DOCKER_PASSWORD should not be injected as pull credentials for docker action containers.
 	assert.Empty(t, captured.Username)

act/runner/expression.go

@@ -13,6 +13,7 @@ import (
 	"reflect"
 	"regexp"
 	"strings"
+	"sync"
 	"time"
 
 	"gitea.com/gitea/runner/act/common"
@@ -71,7 +72,7 @@ func (rc *RunContext) NewExpressionEvaluatorWithEnv(ctx context.Context, env map
 	}
 
 	ghc := rc.getGithubContext(ctx)
-	inputs := getEvaluatorInputs(ctx, rc, rc.actionInputs, ghc)
+	inputs := getEvaluatorInputs(rc, rc.actionInputs, ghc)
 
 	ee := &exprparser.EvaluationEnvironment{
 		Github: ghc,
@@ -81,7 +82,7 @@ func (rc *RunContext) NewExpressionEvaluatorWithEnv(ctx context.Context, env map
 		// todo: should be unavailable
 		// but required to interpolate/evaluate the step outputs on the job
 		Steps:     rc.getStepsContext(),
-		Secrets:   getWorkflowSecrets(ctx, rc),
+		Secrets:   getWorkflowSecrets(rc),
 		Vars:      getWorkflowVars(ctx, rc),
 		Strategy:  strategy,
 		Matrix:    rc.Matrix,
@@ -137,14 +138,14 @@ func (rc *RunContext) newStepExpressionEvaluator(ctx context.Context, step step,
 		Env:      *step.getEnv(),
 		Job:      rc.getJobContext(),
 		Steps:    rc.getStepsContext(),
-		Secrets:  getWorkflowSecrets(ctx, rc),
+		Secrets:  getWorkflowSecrets(rc),
 		Vars:     getWorkflowVars(ctx, rc),
 		Strategy: strategy,
 		Matrix:   rc.Matrix,
 		Needs:    using,
 		// todo: should be unavailable
 		// but required to interpolate/evaluate the inputs in actions/composite
-		Inputs:    getEvaluatorInputs(ctx, rc, stepInputs, rc.getGithubContext(ctx)),
+		Inputs:    getEvaluatorInputs(rc, stepInputs, rc.getGithubContext(ctx)),
 		HashFiles: getHashFilesFunction(ctx, rc),
 	}
 	ee.Runner = rc.getRunnerContext(ctx)
@@ -246,17 +247,18 @@ func (ee expressionEvaluator) EvaluateYamlNode(ctx context.Context, node *yaml.N
 	return ee.shared(ctx).EvaluateYamlNode(node)
 }
 
-func (ee expressionEvaluator) Interpolate(ctx context.Context, in string) string {
-	out, err := ee.interpolate(ctx, in)
-	if err != nil {
-		common.Logger(ctx).Errorf("Unable to interpolate expression '%s': %s", in, err)
-		return ""
-	}
-	return out
+func (ee expressionEvaluator) Interpolate(ctx context.Context, in string) (string, error) {
+	return ee.shared(ctx).Interpolate(in)
 }
 
-func (ee expressionEvaluator) interpolate(ctx context.Context, in string) (string, error) {
-	return ee.shared(ctx).Interpolate(in)
+// InterpolateName keeps the source text of a job or step name that cannot be evaluated, as GitHub does.
+func (ee expressionEvaluator) InterpolateName(ctx context.Context, in string) string {
+	out, err := ee.Interpolate(ctx, in)
+	if err != nil {
+		common.Logger(ctx).Warnf("Unable to evaluate the display name '%s': %s", in, err)
+		return in
+	}
+	return out
 }
 
 // EvalBool evaluates an expression against given evaluator. An `if:` is an expression even without
@@ -277,10 +279,10 @@ func inputsFromEnv(env map[string]string) map[string]any {
 	return inputs
 }
 
-func getEvaluatorInputs(ctx context.Context, rc *RunContext, stepInputs map[string]any, ghc *model.GithubContext) map[string]any {
+func getEvaluatorInputs(rc *RunContext, stepInputs map[string]any, ghc *model.GithubContext) map[string]any {
 	inputs := map[string]any{}
 
-	setupWorkflowInputs(ctx, &inputs, rc)
+	maps.Copy(inputs, rc.workflowCallInputs)
 	maps.Copy(inputs, stepInputs)
 
 	if ghc.EventName == "workflow_dispatch" {
@@ -324,54 +326,49 @@ func coerceInputValue(value any, inputType string) any {
 	return value == "true"
 }
 
-func setupWorkflowInputs(ctx context.Context, inputs *map[string]any, rc *RunContext) {
-	if rc.caller != nil {
-		config := rc.Run.Workflow.WorkflowCallConfig()
+// resolveWorkflowCall evaluates the caller's with: and secrets: once, as the server does before dispatching a called workflow.
+func (rc *RunContext) resolveWorkflowCall(ctx context.Context) error {
+	if rc.caller == nil {
+		return nil
+	}
+	callerJob := rc.caller.runContext.Run.Job()
+	callerEval := rc.caller.runContext.ExprEval
+	calleeEval := sync.OnceValue(func() *expressionEvaluator { return rc.NewExpressionEvaluator(ctx) })
+	config := rc.Run.Workflow.WorkflowCallConfig()
 
-		for name, input := range config.Inputs {
-			value := rc.caller.runContext.Run.Job().With[name]
-			if value != nil {
-				if str, ok := value.(string); ok {
-					// evaluate using the calling RunContext (outside)
-					value = rc.caller.runContext.ExprEval.Interpolate(ctx, str)
-				}
+	rc.workflowCallInputs = make(map[string]any, len(config.Inputs))
+	for name, input := range config.Inputs {
+		value, eval, label := callerJob.With[name], callerEval, "input"
+		if value == nil {
+			value, eval, label = input.Default, calleeEval(), "the default of input"
+		}
+		if str, ok := value.(string); ok {
+			var err error
+			if value, err = eval.Interpolate(ctx, str); err != nil {
+				return fmt.Errorf("unable to interpolate %s %s: %w", label, name, err)
 			}
+		}
+		rc.workflowCallInputs[name] = coerceInputValue(value, input.Type)
+	}
 
-			if value == nil && config != nil && config.Inputs != nil {
-				value = input.Default
-				if rc.ExprEval != nil {
-					if str, ok := value.(string); ok {
-						// evaluate using the called RunContext (inside)
-						value = rc.ExprEval.Interpolate(ctx, str)
-					}
-				}
-			}
-
-			(*inputs)[name] = coerceInputValue(value, input.Type)
+	secrets := callerJob.Secrets()
+	if secrets == nil && callerJob.InheritSecrets() {
+		secrets = rc.caller.runContext.Config.Secrets
+	}
+	rc.workflowCallSecrets = make(map[string]string, len(secrets))
+	for k, v := range secrets {
+		var err error
+		if rc.workflowCallSecrets[k], err = callerEval.Interpolate(ctx, v); err != nil {
+			return fmt.Errorf("unable to interpolate secret %s: %w", k, err)
 		}
 	}
+	return nil
 }
 
-func getWorkflowSecrets(ctx context.Context, rc *RunContext) map[string]string {
+func getWorkflowSecrets(rc *RunContext) map[string]string {
 	if rc.caller != nil {
-		job := rc.caller.runContext.Run.Job()
-		secrets := job.Secrets()
-
-		if secrets == nil && job.InheritSecrets() {
-			secrets = rc.caller.runContext.Config.Secrets
-		}
-
-		// Interpolate into a new map. secrets may be the shared Config.Secrets (or the job's
-		// map), which other parallel jobs read concurrently (e.g. log masking), so mutating it
-		// in place is a data race.
-		interpolated := make(map[string]string, len(secrets))
-		for k, v := range secrets {
-			interpolated[k] = rc.caller.runContext.ExprEval.Interpolate(ctx, v)
-		}
-
-		return interpolated
+		return rc.workflowCallSecrets
 	}
-
 	return rc.Config.Secrets
 }
 

act/runner/expression_test.go

@@ -266,19 +266,21 @@ func TestInterpolate(t *testing.T) {
 		{"${{ null }}", ""},
 		{"${{ fromJSON('[1,2]') }}", "Array"},
 		{"${{ fromJSON('{\"a\":1}') }}", "Object"},
-		// a malformed part must not restructure its neighbours, and it interpolates to nothing
-		{"${{ 1) && (2 }}", ""},
-		{"run ${{ 1) && (2 }} now", ""},
 		{"${{ 1", "${{ 1"},
 	}
 
 	for _, table := range tables {
 		t.Run("interpolate", func(t *testing.T) {
-			assertObject := assert.New(t)
-			out := ee.Interpolate(context.Background(), table.in)
-			assertObject.Equal(table.out, out, table.in)
+			out, err := ee.Interpolate(context.Background(), table.in)
+			require.NoError(t, err, table.in)
+			assert.Equal(t, table.out, out, table.in)
 		})
 	}
+
+	for _, in := range []string{"${{ 1) && (2 }}", "run ${{ 1) && (2 }} now"} {
+		_, err := ee.Interpolate(context.Background(), in)
+		assert.Error(t, err, in)
+	}
 }
 
 func TestGetEvaluatorInputsBoolean(t *testing.T) {
@@ -352,7 +354,7 @@ on:
 				}
 				ghc := &model.GithubContext{EventName: eventName, Event: table.event}
 
-				inputs := getEvaluatorInputs(context.Background(), rc, nil, ghc)
+				inputs := getEvaluatorInputs(rc, nil, ghc)
 				assert.Equal(t, table.flag, inputs["flag"])
 				assert.Equal(t, "gitea", inputs["name"])
 			})
@@ -372,7 +374,8 @@ jobs:
 
 	runner := &runnerImpl{config: &Config{Secrets: map[string]string{"A": "s3cr3t-a", "B": "s3cr3t-b"}}}
 	containerName := func(jobID string) string {
-		rc := runner.newRunContext(t.Context(), &model.Run{JobID: jobID, Workflow: workflow}, nil)
+		rc, err := runner.newRunContext(t.Context(), &model.Run{JobID: jobID, Workflow: workflow}, nil)
+		require.NoError(t, err)
 		assert.NotContains(t, rc.Name, "s3cr3t")
 		return rc.jobContainerName()
 	}

act/runner/job_executor.go

@@ -18,6 +18,7 @@ import (
 	"slices"
 	"strconv"
 	"strings"
+	"sync"
 	"time"
 	"unicode"
 
@@ -154,11 +155,9 @@ func newJobExecutor(info jobInfo, sf stepFactory, rc *RunContext) common.Executo
 		if rc.Run == nil {
 			return nil
 		}
-		rc.ExprEval = rc.NewExpressionEvaluator(ctx)
-		// evaluate environment variables since they can contain
-		// GitHub's special environment variables.
-		for k, v := range rc.GetEnv() {
-			rc.Env[k] = rc.ExprEval.Interpolate(ctx, v)
+		if err := evaluateJobEnvAndDefaults(ctx, rc); err != nil {
+			reportStepError(ctx, rc, err)
+			return err
 		}
 		return nil
 	})
@@ -240,6 +239,8 @@ func newJobExecutor(info jobInfo, sf stepFactory, rc *RunContext) common.Executo
 		// swallowed: a bad output fails this job, it must not abandon the rest of the plan
 		if err := info.interpolateOutputs()(ctx); err != nil {
 			reportStepError(ctx, rc, err)
+		} else if err := setJobOutputs(ctx, rc); err != nil {
+			reportStepError(ctx, rc, err)
 		}
 		return nil
 	})
@@ -258,7 +259,6 @@ func newJobExecutor(info jobInfo, sf stepFactory, rc *RunContext) common.Executo
 			logger.Errorf("##[error]%s", EscapeCommandData("Error while stop job container: "+err.Error()))
 		}
 		setJobResult(ctx, info, rc, jobError == nil)
-		setJobOutputs(ctx, rc)
 
 		return err
 	})
@@ -413,30 +413,58 @@ func setJobResult(ctx context.Context, info jobInfo, rc *RunContext, success boo
 	logger.WithField("jobResult", jobResult).Infof("Job %s", jobResultMessage)
 }
 
-func setJobOutputs(ctx context.Context, rc *RunContext) {
-	if rc.caller != nil {
-		// map outputs for reusable workflows
-		callerOutputs := make(map[string]string)
-
-		ee := rc.NewExpressionEvaluator(ctx)
-
-		for k, v := range rc.Run.Workflow.WorkflowCallConfig().Outputs {
-			callerOutputs[k] = ee.Interpolate(ctx, ee.Interpolate(ctx, v.Value))
+// evaluateJobEnvAndDefaults resolves the job's env and defaults.run once, as GitHub does at job setup.
+func evaluateJobEnvAndDefaults(ctx context.Context, rc *RunContext) error {
+	rc.ExprEval = rc.NewExpressionEvaluator(ctx)
+	var err error
+	for k, v := range rc.GetEnv() {
+		if rc.Env[k], err = rc.ExprEval.Interpolate(ctx, v); err != nil {
+			return fmt.Errorf("unable to interpolate env %s: %w", k, err)
 		}
-
-		// Matrix combinations of a reusable-workflow caller share the caller's *model.Job;
-		// serialize the write so parallel combos don't race on its Outputs field.
-		callerJob := rc.caller.runContext.Run.Job()
-		defer lockJob(callerJob)()
-		callerJob.Outputs = callerOutputs
 	}
+	defaults := rc.Run.Job().Defaults.Run
+	if rc.jobRunDefaults.Shell, err = rc.ExprEval.Interpolate(ctx, defaults.Shell); err != nil {
+		return fmt.Errorf("unable to interpolate defaults.run.shell: %w", err)
+	}
+	if rc.jobRunDefaults.WorkingDirectory, err = rc.ExprEval.Interpolate(ctx, defaults.WorkingDirectory); err != nil {
+		return fmt.Errorf("unable to interpolate defaults.run.working-directory: %w", err)
+	}
+	return nil
+}
+
+func setJobOutputs(ctx context.Context, rc *RunContext) error {
+	if rc.caller == nil {
+		return nil
+	}
+	outputs := rc.Run.Workflow.WorkflowCallConfig().Outputs
+	callerOutputs := make(map[string]string, len(outputs))
+	ee := sync.OnceValue(func() *expressionEvaluator { return rc.NewExpressionEvaluator(ctx) })
+	for k, v := range outputs {
+		value := v.Value
+		for range 2 { // two passes, the value resolves through a job output
+			var err error
+			if value, err = ee().Interpolate(ctx, value); err != nil {
+				return fmt.Errorf("unable to interpolate workflow output %s: %w", k, err)
+			}
+		}
+		callerOutputs[k] = value
+	}
+
+	// Matrix combinations of a reusable-workflow caller share the caller's *model.Job;
+	// serialize the write so parallel combos don't race on its Outputs field.
+	callerJob := rc.caller.runContext.Run.Job()
+	defer lockJob(callerJob)()
+	callerJob.Outputs = callerOutputs
+	return nil
 }
 
 // applyJobTimeout applies the job-level timeout-minutes to ctx, mirroring the
 // step-level evaluateStepTimeout in step.go.
 func applyJobTimeout(ctx context.Context, rc *RunContext, job *model.Job) (context.Context, context.CancelFunc) {
-	timeout := rc.ExprEval.Interpolate(ctx, job.TimeoutMinutes)
-	if timeout != "" {
+	timeout, err := rc.ExprEval.Interpolate(ctx, job.TimeoutMinutes)
+	if err != nil {
+		common.Logger(ctx).Errorf("An error occurred when attempting to determine the job timeout: %s", err)
+	} else if timeout != "" {
 		if timeoutMinutes, err := strconv.ParseInt(timeout, 10, 64); err == nil {
 			return context.WithTimeout(ctx, time.Duration(timeoutMinutes)*time.Minute)
 		}
@@ -635,7 +663,7 @@ func archiveEntryMatchesPath(entryName, requestedPath string) bool {
 
 func useStepLogger(rc *RunContext, stepModel *model.Step, stage stepStage, executor common.Executor) common.Executor {
 	return func(ctx context.Context) error {
-		ctx = withStepLogger(ctx, stepModel.Number, stepModel.ID, rc.ExprEval.Interpolate(ctx, stepModel.String()), stage.String())
+		ctx = withStepLogger(ctx, stepModel.Number, stepModel.ID, rc.ExprEval.InterpolateName(ctx, stepModel.String()), stage.String())
 
 		logWriter := rc.commandLogWriter(ctx)
 

act/runner/reusable_workflow.go

@@ -95,9 +95,12 @@ func newRemoteReusableWorkflowExecutor(rc *RunContext) common.Executor {
 // remoteReusableWorkflow.URL = rc.getGithubContext(ctx).ServerURL
 func cloneRemoteReusableWorkflow(rc *RunContext, cloneURL, ref, targetDirectory, token string) common.Executor {
 	return func(ctx context.Context) error {
-		cloneURL = rc.NewExpressionEvaluator(ctx).Interpolate(ctx, cloneURL)
+		interpolatedURL, err := rc.NewExpressionEvaluator(ctx).Interpolate(ctx, cloneURL)
+		if err != nil {
+			return fmt.Errorf("unable to interpolate the workflow clone URL: %w", err)
+		}
 		return git.NewGitCloneExecutor(git.NewGitCloneExecutorInput{
-			URL:         cloneURL,
+			URL:         interpolatedURL,
 			Ref:         ref,
 			Dir:         targetDirectory,
 			Token:       token,

act/runner/run_context.go

@@ -17,6 +17,7 @@ import (
 	"io"
 	maps0 "maps"
 	"os"
+	"path"
 	"path/filepath"
 	"regexp"
 	"runtime"
@@ -28,6 +29,7 @@ import (
 	"gitea.com/gitea/runner/act/common"
 	"gitea.com/gitea/runner/act/container"
 	"gitea.com/gitea/runner/act/ghcontext"
+	"gitea.com/gitea/runner/internal/pkg/labels"
 	"gitea.com/gitea/runner/internal/pkg/lock"
 
 	"gitea.dev/actionslib/pkg/exprparser"
@@ -67,7 +69,11 @@ type RunContext struct {
 	actionInputs        map[string]any // inputs of the composite action this runs, nil for a job
 	Masks               []string
 	cleanUpJobContainer common.Executor
-	caller              *caller // job calling this RunContext (reusable workflows)
+	caller              *caller           // job calling this RunContext (reusable workflows)
+	workflowCallInputs  map[string]any    // the caller's with:, resolved once by resolveWorkflowCall
+	workflowCallSecrets map[string]string // the caller's secrets:, resolved once by resolveWorkflowCall
+	jobRunDefaults      model.RunDefaults // defaults.run, resolved once at job setup as GitHub does
+	platformImage       string            // container.image or the runs-on pick, resolved once by isEnabled
 	// summaryFileInitialized tracks which per-step summary files (workflow/step-summary-N.md)
 	// have already been created on the JobContainer. The runner sets up file-command files
 	// via JobContainer.Copy at the start of every phase, which truncates them — fine for
@@ -246,6 +252,9 @@ func (rc *RunContext) validVolumes() []string {
 	if rc.Config.SharedToolCache {
 		volumes = append(volumes, sharedToolCacheVolume)
 	}
+	if rc.Config.BindWorkdir {
+		volumes = append(volumes, rc.Config.Workdir)
+	}
 	// TODO: add a new configuration to control whether the docker daemon can be mounted
 	return append(volumes, name, name+"-env",
 		getDockerDaemonSocketMountPath(rc.containerDaemonSocket()))
@@ -299,7 +308,7 @@ func splitVolumes(specs []string) ([]string, map[string]string, map[string]bool)
 }
 
 // Returns the binds and mounts for the container, resolving paths as appopriate
-func (rc *RunContext) GetBindsAndMounts() ([]string, map[string]string) {
+func (rc *RunContext) GetBindsAndMounts() ([]string, map[string]string, error) {
 	name := rc.jobContainerName()
 	ext := container.LinuxContainerEnvironmentExtensions{}
 
@@ -308,7 +317,10 @@ func (rc *RunContext) GetBindsAndMounts() ([]string, map[string]string) {
 		if container := job.Container(); container != nil {
 			for _, v := range container.Volumes {
 				if rc.ExprEval != nil {
-					v = rc.ExprEval.Interpolate(context.Background(), v)
+					var err error
+					if v, err = rc.ExprEval.Interpolate(context.Background(), v); err != nil {
+						return nil, nil, fmt.Errorf("unable to interpolate container.volumes: %w", err)
+					}
 				}
 				volumes = append(volumes, v)
 			}
@@ -342,7 +354,7 @@ func (rc *RunContext) GetBindsAndMounts() ([]string, map[string]string) {
 		}
 	}
 
-	return binds, mounts
+	return binds, mounts, nil
 }
 
 func (rc *RunContext) startHostEnvironment() common.Executor {
@@ -414,6 +426,113 @@ func (rc *RunContext) startHostEnvironment() common.Executor {
 	}
 }
 
+// printStartMacOSVMGroup mirrors the "Starting job container" section for macOS VMs.
+func printStartMacOSVMGroup(ctx context.Context, image, name string) func() {
+	rawLogger := common.Logger(ctx).WithField(rawOutputField, true)
+	rawLogger.Infof("::group::Starting job VM")
+	rawLogger.Infof("image: %s", image)
+	rawLogger.Infof("name: %s", name)
+	return func() {
+		rawLogger.Infof("::endgroup::")
+	}
+}
+
+func (rc *RunContext) startMacOSVMEnvironment() common.Executor {
+	return func(ctx context.Context) error {
+		if len(rc.Run.Job().Services) > 0 {
+			return errors.New("service containers are not supported with the macOS VM executor; see docs/macos-vm-executor.md")
+		}
+
+		image := rc.macOSVMImage()
+		logWriter := rc.commandLogWriter(ctx)
+		name := rc.macOSVMName()
+		rc.Env["JOB_CONTAINER_NAME"] = name
+
+		guestWorkdir := rc.macOSVMGuestWorkdir()
+		scratch := path.Join("/", rc.macOSVMWorkdirParent(), "scratch", name)
+		actPath := path.Join(scratch, "act")
+		tmpDir := path.Join(scratch, "tmp")
+		toolCache := rc.toolCache(path.Join(scratch, "tool_cache"))
+
+		jobContainer, err := container.NewMacOSVMEnvironment(container.MacOSVMEnvironmentInput{
+			Path:         scratch,
+			TmpDir:       tmpDir,
+			ToolCache:    toolCache,
+			Workdir:      rc.Config.Workdir,
+			GuestWorkdir: guestWorkdir,
+			ActPath:      actPath,
+			Image:        image,
+			VMName:       name,
+			ExecutorPath: rc.Config.MacOSVM.ExecutorPath,
+			CPU:          rc.Config.MacOSVM.CPU,
+			Memory:       rc.Config.MacOSVM.Memory,
+			BootTimeout:  rc.Config.MacOSVM.BootTimeout,
+			Stdout:       logWriter,
+			Stderr:       logWriter,
+		})
+		if err != nil {
+			return err
+		}
+		rc.JobContainer = jobContainer
+		rc.cleanUpJobContainer = jobContainer.Remove()
+
+		for k, v := range rc.getRunnerContext(ctx) {
+			if v, ok := v.(string); ok {
+				rc.Env["RUNNER_"+strings.ToUpper(k)] = v
+			}
+		}
+		for _, env := range os.Environ() {
+			if k, v, ok := strings.Cut(env, "="); ok {
+				if _, ok := rc.Env[k]; !ok {
+					rc.Env[k] = v
+				}
+			}
+		}
+
+		defer printStartMacOSVMGroup(ctx, image, name)()
+		return common.NewPipelineExecutor(
+			jobContainer.Pull(rc.Config.ForcePull),
+			jobContainer.Create(nil, nil),
+			jobContainer.Start(false),
+			jobContainer.Exec([]string{"/bin/mkdir", "-p", guestWorkdir, actPath, tmpDir, toolCache}, nil, "", "/"),
+			rc.captureJobContainerInfo(),
+			jobContainer.Copy(jobContainer.GetActPath()+"/", &container.FileEntry{
+				Name: "workflow/event.json",
+				Mode: 0o644,
+				Body: rc.EventJSON,
+			}, &container.FileEntry{
+				Name: "workflow/envs.txt",
+				Mode: 0o666,
+				Body: "",
+			}),
+		)(ctx)
+	}
+}
+
+func (rc *RunContext) macOSVMImage() string {
+	return strings.TrimPrefix(rc.platformImage, labels.MacOSVMSchemePrefix)
+}
+
+func (rc *RunContext) macOSVMName() string {
+	nameParts := []string{"GITEA-MACOS-VM", rc.Config.RunnerUUID, rc.Config.ContainerNamePrefix, "WORKFLOW-" + rc.Run.Workflow.Name, "JOB-" + rc.Run.JobID, rc.Name}
+	if rc.caller != nil {
+		nameParts = append(nameParts, "CALLED-BY-"+rc.caller.runContext.JobName)
+	}
+	return createContainerName(nameParts...)
+}
+
+func (rc *RunContext) macOSVMGuestWorkdir() string {
+	rel := strings.TrimLeft(filepath.ToSlash(rc.Config.Workdir), "/")
+	return path.Join("/", rc.macOSVMWorkdirParent(), rel)
+}
+
+func (rc *RunContext) macOSVMWorkdirParent() string {
+	if rc.Config.MacOSVM.WorkdirParent != "" {
+		return rc.Config.MacOSVM.WorkdirParent
+	}
+	return "/Users/admin/runner"
+}
+
 // printStartJobContainerGroup mirrors actions/runner's "Starting job container"
 // section: emit the group header and summary, return a closer for ::endgroup::.
 func printStartJobContainerGroup(ctx context.Context, image, name, network string) func() {
@@ -433,7 +552,7 @@ var newContainer = container.NewContainer
 func (rc *RunContext) startJobContainer() common.Executor {
 	return func(ctx context.Context) error {
 		logger := common.Logger(ctx)
-		image := rc.platformImage(ctx)
+		image := rc.platformImage
 		logWriter := rc.commandLogWriter(ctx)
 
 		username, password, err := rc.handleCredentials(ctx)
@@ -452,7 +571,10 @@ func (rc *RunContext) startJobContainer() common.Executor {
 		envList = append(envList, fmt.Sprintf("%s=%s", "LANG", "C.UTF-8")) // Use same locale as GitHub Actions
 
 		ext := container.LinuxContainerEnvironmentExtensions{}
-		binds, mounts := rc.GetBindsAndMounts()
+		binds, mounts, err := rc.GetBindsAndMounts()
+		if err != nil {
+			return err
+		}
 
 		// specify the network to which the container will connect when `docker create` stage. (like execute command line: docker create --network <networkName> <image>)
 		// if using service containers, will create a new network for the containers.
@@ -463,7 +585,10 @@ func (rc *RunContext) startJobContainer() common.Executor {
 		for serviceID, spec := range rc.Run.Job().Services {
 			// GitHub compatibility: skip services whose image evaluates to an
 			// empty string, enabling conditional services via expressions
-			serviceImage := rc.ExprEval.Interpolate(ctx, spec.Image)
+			serviceImage, err := rc.ExprEval.Interpolate(ctx, spec.Image)
+			if err != nil {
+				return fmt.Errorf("unable to interpolate service %s image: %w", serviceID, err)
+			}
 			if serviceImage == "" {
 				logger.Infof("The service '%s' will not be started because the container definition has an empty image.", serviceID)
 				continue
@@ -473,16 +598,20 @@ func (rc *RunContext) startJobContainer() common.Executor {
 			// a service reaches the internet the way the job does; its own env still wins
 			maps0.Copy(interpolatedEnvs, rc.Config.ProxyEnv)
 			for k, v := range spec.Env {
-				interpolatedEnvs[k] = rc.ExprEval.Interpolate(ctx, v)
+				if interpolatedEnvs[k], err = rc.ExprEval.Interpolate(ctx, v); err != nil {
+					return fmt.Errorf("unable to interpolate service %s env %s: %w", serviceID, k, err)
+				}
 			}
 			envs := make([]string, 0, len(interpolatedEnvs))
 			for k, v := range interpolatedEnvs {
 				envs = append(envs, fmt.Sprintf("%s=%s", k, v))
 			}
 			// interpolate cmd
-			interpolatedCmd := make([]string, 0, len(spec.Cmd))
-			for _, v := range spec.Cmd {
-				interpolatedCmd = append(interpolatedCmd, rc.ExprEval.Interpolate(ctx, v))
+			interpolatedCmd := make([]string, len(spec.Cmd))
+			for i, v := range spec.Cmd {
+				if interpolatedCmd[i], err = rc.ExprEval.Interpolate(ctx, v); err != nil {
+					return fmt.Errorf("unable to interpolate service %s command: %w", serviceID, err)
+				}
 			}
 			// keep these local: reusing username/password would overwrite the
 			// credentials the job container is pulled with further down
@@ -491,20 +620,28 @@ func (rc *RunContext) startJobContainer() common.Executor {
 				return fmt.Errorf("failed to handle service %s credentials: %w", serviceID, err)
 			}
 
-			interpolatedVolumes := make([]string, 0, len(spec.Volumes))
-			for _, volume := range spec.Volumes {
-				interpolatedVolumes = append(interpolatedVolumes, rc.ExprEval.Interpolate(ctx, volume))
+			interpolatedVolumes := make([]string, len(spec.Volumes))
+			for i, volume := range spec.Volumes {
+				if interpolatedVolumes[i], err = rc.ExprEval.Interpolate(ctx, volume); err != nil {
+					return fmt.Errorf("unable to interpolate service %s volumes: %w", serviceID, err)
+				}
 			}
 			serviceBinds, serviceMounts, _ := splitVolumes(interpolatedVolumes)
 
-			interpolatedPorts := make([]string, 0, len(spec.Ports))
-			for _, port := range spec.Ports {
-				interpolatedPorts = append(interpolatedPorts, rc.ExprEval.Interpolate(ctx, port))
+			interpolatedPorts := make([]string, len(spec.Ports))
+			for i, port := range spec.Ports {
+				if interpolatedPorts[i], err = rc.ExprEval.Interpolate(ctx, port); err != nil {
+					return fmt.Errorf("unable to interpolate service %s ports: %w", serviceID, err)
+				}
 			}
 			exposedPorts, portBindings, err := nat.ParsePortSpecs(interpolatedPorts)
 			if err != nil {
 				return fmt.Errorf("failed to parse service %s ports: %w", serviceID, err)
 			}
+			serviceOptions, err := rc.ExprEval.Interpolate(ctx, spec.Options)
+			if err != nil {
+				return fmt.Errorf("unable to interpolate service %s options: %w", serviceID, err)
+			}
 
 			serviceContainerName := createContainerName(rc.jobContainerName(), serviceID)
 			c := newContainer(&container.NewContainerInput{
@@ -522,7 +659,7 @@ func (rc *RunContext) startJobContainer() common.Executor {
 				UsernsMode:      rc.Config.UsernsMode,
 				Platform:        rc.Config.ContainerArchitecture,
 				AutoRemove:      false, // so a dead service's log survives, cleanupJobResources removes it
-				WorkflowOptions: rc.ExprEval.Interpolate(ctx, spec.Options),
+				WorkflowOptions: serviceOptions,
 				NetworkMode:     networkName,
 				NetworkAliases:  []string{serviceID},
 				ExposedPorts:    exposedPorts,
@@ -538,6 +675,10 @@ func (rc *RunContext) startJobContainer() common.Executor {
 		// For Gitea, `jobContainerNetwork` should be the same as `networkName`
 		jobContainerNetwork := networkName
 
+		workflowOptions, err := rc.workflowOptions(ctx)
+		if err != nil {
+			return err
+		}
 		rc.JobContainer = newContainer(&container.NewContainerInput{
 			Cmd:             nil,
 			Entrypoint:      []string{"/bin/sleep", fmt.Sprint(rc.Config.ContainerMaxLifetime.Round(time.Second).Seconds())},
@@ -557,7 +698,7 @@ func (rc *RunContext) startJobContainer() common.Executor {
 			UsernsMode:      rc.Config.UsernsMode,
 			Platform:        rc.Config.ContainerArchitecture,
 			RunnerOptions:   rc.Config.ContainerOptions,
-			WorkflowOptions: rc.workflowOptions(ctx),
+			WorkflowOptions: workflowOptions,
 			AutoRemove:      true,
 			ValidVolumes:    rc.validVolumes(),
 			AllocatePTY:     rc.Config.AllocatePTY,
@@ -928,7 +1069,7 @@ func (rc *RunContext) interpolateOutputs() common.Executor {
 		outputs := make(map[string]string, len(rc.outputTemplate))
 		var err error
 		for k, v := range rc.outputTemplate {
-			if outputs[k], err = ee.interpolate(ctx, v); err != nil {
+			if outputs[k], err = ee.Interpolate(ctx, v); err != nil {
 				err = fmt.Errorf("failed to evaluate job output %q: %w", k, err)
 				break
 			}
@@ -948,9 +1089,12 @@ func (rc *RunContext) interpolateOutputs() common.Executor {
 func (rc *RunContext) startContainer() common.Executor {
 	return func(ctx context.Context) error {
 		var err error
-		if rc.IsHostEnv(ctx) {
+		switch {
+		case rc.IsHostEnv():
 			err = rc.startHostEnvironment()(ctx)
-		} else {
+		case rc.IsMacOSVMEnv():
+			err = rc.startMacOSVMEnvironment()(ctx)
+		default:
 			err = rc.startJobContainer()(ctx)
 		}
 		if err != nil {
@@ -978,10 +1122,13 @@ func (rc *RunContext) cleanupFailedStart(ctx context.Context) {
 	}
 }
 
-func (rc *RunContext) IsHostEnv(ctx context.Context) bool {
-	platform := rc.runsOnImage(ctx)
-	image := rc.containerImage(ctx)
-	return image == "" && strings.EqualFold(platform, "-self-hosted")
+func (rc *RunContext) IsHostEnv() bool {
+	return strings.EqualFold(rc.platformImage, "-self-hosted")
+}
+
+// IsMacOSVMEnv reports whether the resolved platform image requests a macOS VM.
+func (rc *RunContext) IsMacOSVMEnv() bool {
+	return strings.HasPrefix(rc.platformImage, labels.MacOSVMSchemePrefix)
 }
 
 func (rc *RunContext) stopContainer() common.Executor {
@@ -1066,32 +1213,35 @@ func (rc *RunContext) Executor() (common.Executor, error) {
 	}, nil
 }
 
-func (rc *RunContext) containerImage(ctx context.Context) string {
-	job := rc.Run.Job()
-
-	c := job.Container()
-	if c != nil {
-		return rc.ExprEval.Interpolate(ctx, c.Image)
+func (rc *RunContext) containerImage(ctx context.Context) (string, error) {
+	c := rc.Run.Job().Container()
+	if c == nil {
+		return "", nil
 	}
-
-	return ""
+	image, err := rc.ExprEval.Interpolate(ctx, c.Image)
+	if err != nil {
+		return "", fmt.Errorf("unable to interpolate container.image: %w", err)
+	}
+	return image, nil
 }
 
-func (rc *RunContext) runsOnImage(ctx context.Context) string {
+func (rc *RunContext) runsOnImage(ctx context.Context) (string, error) {
 	if rc.Run.Job().RunsOn() == nil {
 		common.Logger(ctx).Errorf("'runs-on' key not defined in %s", rc.String())
 	}
 
-	job := rc.Run.Job()
-	runsOn := job.RunsOn()
+	runsOn := rc.Run.Job().RunsOn()
 	for i, v := range runsOn {
-		runsOn[i] = rc.ExprEval.Interpolate(ctx, v)
+		var err error
+		if runsOn[i], err = rc.ExprEval.Interpolate(ctx, v); err != nil {
+			return "", fmt.Errorf("unable to interpolate runs-on: %w", err)
+		}
 	}
 
 	if rc.Config.PlatformPicker != nil {
-		return rc.Config.PlatformPicker(runsOn)
+		return rc.Config.PlatformPicker(runsOn), nil
 	}
-	return ""
+	return "", nil
 }
 
 func (rc *RunContext) runsOnPlatformNames(ctx context.Context) []string {
@@ -1112,21 +1262,26 @@ func (rc *RunContext) runsOnPlatformNames(ctx context.Context) []string {
 	return model.RunsOnFromNode(rawRunsOn)
 }
 
-func (rc *RunContext) platformImage(ctx context.Context) string {
-	if containerImage := rc.containerImage(ctx); containerImage != "" {
-		return containerImage
+// resolvePlatformImage evaluates the job's image once, so every consumer sees the image the job started with.
+func (rc *RunContext) resolvePlatformImage(ctx context.Context) error {
+	image, err := rc.containerImage(ctx)
+	if err == nil && image == "" {
+		image, err = rc.runsOnImage(ctx)
 	}
-
-	return rc.runsOnImage(ctx)
+	rc.platformImage = image
+	return err
 }
 
-func (rc *RunContext) workflowOptions(ctx context.Context) string {
+func (rc *RunContext) workflowOptions(ctx context.Context) (string, error) {
 	c := rc.Run.Job().Container()
 	if c == nil {
-		return ""
+		return "", nil
 	}
-
-	return rc.ExprEval.Interpolate(ctx, c.Options)
+	options, err := rc.ExprEval.Interpolate(ctx, c.Options)
+	if err != nil {
+		return "", fmt.Errorf("unable to interpolate container.options: %w", err)
+	}
+	return options, nil
 }
 
 func (rc *RunContext) isEnabled(ctx context.Context) (bool, error) {
@@ -1156,8 +1311,10 @@ func (rc *RunContext) isEnabled(ctx context.Context) (bool, error) {
 		return true, nil
 	}
 
-	img := rc.platformImage(ctx)
-	if img == "" {
+	if err := rc.resolvePlatformImage(ctx); err != nil {
+		return false, err
+	}
+	if rc.platformImage == "" {
 		for _, platformName := range rc.runsOnPlatformNames(ctx) {
 			l.Infof("Skipping unsupported platform -- Try running with `-P %+v=...`", platformName)
 		}
@@ -1544,7 +1701,7 @@ func (rc *RunContext) imageOS(ctx context.Context) string {
 		// log that runs-on is missing.
 		return ""
 	}
-	if imageOS := imageOSFromImage(rc.platformImage(ctx)); imageOS != "" {
+	if imageOS := imageOSFromImage(rc.platformImage); imageOS != "" {
 		return imageOS
 	}
 
@@ -1606,14 +1763,23 @@ func (rc *RunContext) interpolateCredentials(ctx context.Context, credentials ma
 	}
 
 	ee := rc.NewExpressionEvaluator(ctx)
-	username := ee.Interpolate(ctx, credentials["username"])
-	if username == "" {
-		return "", "", errors.New("failed to interpolate " + prefix + "credentials.username")
+	interpolate := func(key string) (string, error) {
+		value, err := ee.Interpolate(ctx, credentials[key])
+		if err != nil {
+			return "", fmt.Errorf("failed to interpolate %scredentials.%s: %w", prefix, key, err)
+		}
+		if value == "" {
+			return "", fmt.Errorf("failed to interpolate %scredentials.%s", prefix, key)
+		}
+		return value, nil
 	}
-	password := ee.Interpolate(ctx, credentials["password"])
-	if password == "" {
-		return "", "", errors.New("failed to interpolate " + prefix + "credentials.password")
+	username, err := interpolate("username")
+	if err != nil {
+		return "", "", err
+	}
+	password, err := interpolate("password")
+	if err != nil {
+		return "", "", err
 	}
-
 	return username, password, nil
 }

act/runner/run_context_test.go

@@ -18,6 +18,7 @@ import (
 
 	"gitea.com/gitea/runner/act/common"
 	"gitea.com/gitea/runner/act/container"
+	"gitea.com/gitea/runner/internal/pkg/labels"
 
 	"gitea.dev/actionslib/pkg/exprparser"
 	"gitea.dev/actionslib/pkg/model"
@@ -267,6 +268,7 @@ func startJobContainerInputs(t *testing.T, workflowYAML string, cfg *Config) []*
 		},
 	}
 	rc.ExprEval = rc.NewExpressionEvaluator(t.Context())
+	require.NoError(t, rc.resolvePlatformImage(t.Context()))
 
 	// the inputs are built before the missing daemon fails the first call
 	t.Setenv("DOCKER_HOST", "unix:///nonexistent.sock")
@@ -451,7 +453,8 @@ func TestRunContext_GetBindsAndMounts(t *testing.T) {
 					config := testcase.rc.Config
 					config.Workdir = testcase.name
 					config.BindWorkdir = bindWorkDir
-					gotbind, gotmount := rctemplate.GetBindsAndMounts()
+					gotbind, gotmount, err := rctemplate.GetBindsAndMounts()
+					require.NoError(t, err)
 
 					// Name binds/mounts are either/or
 					if config.BindWorkdir {
@@ -510,7 +513,8 @@ func TestRunContext_GetBindsAndMounts(t *testing.T) {
 			rc.Run.Workflow.Jobs = map[string]*model.Job{"job1": job}
 			rc.ExprEval = rc.NewExpressionEvaluator(context.Background())
 
-			gotbind, gotmount := rc.GetBindsAndMounts()
+			gotbind, gotmount, err := rc.GetBindsAndMounts()
+			require.NoError(t, err)
 			assert.Contains(t, gotbind, "/host/mame/roms:/root/.mame/roms:ro")
 			assert.NotContains(t, gotbind, "${{ secrets.MAME }}")
 			assert.NotContains(t, gotmount, "${{ secrets.MAME }}")
@@ -539,7 +543,8 @@ func TestRunContext_GetBindsAndMounts(t *testing.T) {
 				rc.Run.JobID = "job1"
 				rc.Run.Workflow.Jobs = map[string]*model.Job{"job1": job}
 
-				gotbind, gotmount := rc.GetBindsAndMounts()
+				gotbind, gotmount, err := rc.GetBindsAndMounts()
+				require.NoError(t, err)
 
 				if len(testcase.wantbind) > 0 {
 					assert.Contains(t, gotbind, testcase.wantbind)
@@ -574,11 +579,13 @@ func TestRunContext_GetBindsAndMounts(t *testing.T) {
 			Config: &Config{},
 		}
 
-		_, gotmount := rc.GetBindsAndMounts()
+		_, gotmount, err := rc.GetBindsAndMounts()
+		require.NoError(t, err)
 		assert.NotContains(t, gotmount, sharedToolCacheVolume)
 
 		rc.Config.SharedToolCache = true
-		_, gotmount = rc.GetBindsAndMounts()
+		_, gotmount, err = rc.GetBindsAndMounts()
+		require.NoError(t, err)
 		assert.Equal(t, container.DefaultToolCache, gotmount[sharedToolCacheVolume])
 	})
 }
@@ -604,6 +611,11 @@ func TestRunContextValidVolumes(t *testing.T) {
 	// a job may mount it only while the runner does
 	rc.Config.SharedToolCache = false
 	assert.NotContains(t, rc.validVolumes(), sharedToolCacheVolume)
+
+	rc.Config.Workdir = "/workspace/1/owner/repo"
+	assert.NotContains(t, rc.validVolumes(), rc.Config.Workdir)
+	rc.Config.BindWorkdir = true
+	assert.Contains(t, rc.validVolumes(), rc.Config.Workdir)
 }
 
 func TestCleanupJobResourcesCleansServicesWithoutJobContainer(t *testing.T) {
@@ -655,8 +667,10 @@ func TestInterpolateOutputsIsPerMatrixCombo(t *testing.T) {
 	r := &runnerImpl{config: &Config{}}
 	ctx := context.Background()
 
-	rcA := r.newRunContext(ctx, run, map[string]any{"v": "a"})
-	rcB := r.newRunContext(ctx, run, map[string]any{"v": "b"})
+	rcA, err := r.newRunContext(ctx, run, map[string]any{"v": "a"})
+	require.NoError(t, err)
+	rcB, err := r.newRunContext(ctx, run, map[string]any{"v": "b"})
+	require.NoError(t, err)
 
 	require.NoError(t, rcA.interpolateOutputs()(ctx))
 	require.NoError(t, rcB.interpolateOutputs()(ctx))
@@ -1329,12 +1343,14 @@ func TestRunContextImageOS(t *testing.T) {
 	t.Run("prefers the release in the resolved image tag", func(t *testing.T) {
 		rc := createRunsOnRunContext(t, "ubuntu-latest")
 		rc.Config.PlatformPicker = func([]string) string { return "docker.gitea.com/runner-images:ubuntu-24.04" }
+		require.NoError(t, rc.resolvePlatformImage(ctx))
 		assert.Equal(t, "ubuntu24", rc.imageOS(ctx))
 	})
 
 	t.Run("falls back to the runs-on label", func(t *testing.T) {
 		rc := createRunsOnRunContext(t, "ubuntu-22.04")
 		rc.Config.PlatformPicker = func([]string) string { return "some-image" }
+		require.NoError(t, rc.resolvePlatformImage(ctx))
 		assert.Equal(t, "ubuntu22", rc.imageOS(ctx))
 	})
 
@@ -1443,3 +1459,25 @@ func TestRunContextWithGithubEnvRunnerValues(t *testing.T) {
 	assert.Equal(t, "/workspace/owner", env["RUNNER_WORKSPACE"])
 	assert.Equal(t, "1", env["RUNNER_DEBUG"])
 }
+
+func TestRunContextMacOSVMPlatform(t *testing.T) {
+	rc := createRunsOnRunContext(t, "macos-latest")
+	rc.Config.PlatformPicker = func([]string) string {
+		return labels.MacOSVMSchemePrefix + "ghcr.io/cirruslabs/macos-sonoma-base:latest"
+	}
+	require.NoError(t, rc.resolvePlatformImage(t.Context()))
+
+	assert.True(t, rc.IsMacOSVMEnv())
+	assert.False(t, rc.IsHostEnv())
+	assert.Equal(t, "ghcr.io/cirruslabs/macos-sonoma-base:latest", rc.macOSVMImage())
+}
+
+func TestRunContextMacOSVMGuestWorkdir(t *testing.T) {
+	rc := createRunsOnRunContext(t, "macos-latest")
+	rc.Config.Workdir = "/workspace/owner/repo"
+	rc.Config.MacOSVM.WorkdirParent = "/Users/admin/runner"
+	rc.Config.RunnerUUID = "runner-1"
+
+	assert.Equal(t, "/Users/admin/runner/workspace/owner/repo", rc.macOSVMGuestWorkdir())
+	assert.Contains(t, rc.macOSVMName(), "GITEA-MACOS-VM-runner-1-")
+}

act/runner/runner.go

@@ -79,9 +79,20 @@ type Config struct {
 	MaxParallel                       int           // max parallel jobs to run across all workflows (0 = no limit, uses CPU count)
 	AllocatePTY                       bool          // allocate a pseudo-TTY for each step's process
 	ServiceReadyTimeout               time.Duration // how long a job waits for its service containers to report healthy (0 uses the default)
+	RunnerUUID                        string        // UUID this runner registered with, used to identify its macOS VMs
 	RunnerName                        string        // name this runner registered with, reported as `runner.name`, defaults to the hostname
 	JobStartedHook                    string        // script run inside the job environment before the job's first step; ACTIONS_RUNNER_HOOK_JOB_STARTED is read from Env when empty
 	JobCompletedHook                  string        // script run inside the job environment after the job's last step; ACTIONS_RUNNER_HOOK_JOB_COMPLETED is read from Env when empty
+	MacOSVM                           MacOSVMConfig // configures the macOS VM executor
+}
+
+// MacOSVMConfig contains the macOS VM executor settings that come from the runner config.
+type MacOSVMConfig struct {
+	ExecutorPath  string        // path to the runner-executor-macos binary
+	WorkdirParent string        // guest directory under which the job workspace is created
+	CPU           int           // number of virtual CPUs, 0 keeps the image default
+	Memory        int           // VM memory in megabytes, 0 keeps the image default
+	BootTimeout   time.Duration // how long to wait for the VM to become ready
 }
 
 // RunnerDebug reports whether debug logging is on, exposed as `runner.debug` and
@@ -198,7 +209,10 @@ func (runner *runnerImpl) NewPlanExecutor(plan *model.Plan) common.Executor {
 					log.Debugf("Job.Strategy.MaxParallelString: %v", job.Strategy.MaxParallelString)
 					log.Debugf("Job.Strategy.RawMatrix: %v", job.Strategy.RawMatrix)
 
-					strategyRc := runner.newRunContext(ctx, run, nil)
+					strategyRc, err := runner.newRunContext(ctx, run, nil)
+					if err != nil {
+						return err
+					}
 					// Resolve template expressions in the matrix node before Matrix() is called.
 					// On failure the literal string is kept and normalizeMatrixValue wraps it as a fallback.
 					if err := strategyRc.NewExpressionEvaluator(ctx).EvaluateYamlNode(ctx, &job.Strategy.RawMatrix); err != nil {
@@ -230,7 +244,10 @@ func (runner *runnerImpl) NewPlanExecutor(plan *model.Plan) common.Executor {
 				log.Infof("Running job with maxParallel=%d for %d matrix combinations", maxParallel, len(matrixes))
 
 				for i, matrix := range matrixes {
-					rc := runner.newRunContext(ctx, run, matrix)
+					rc, err := runner.newRunContext(ctx, run, matrix)
+					if err != nil {
+						return err
+					}
 					rc.JobName = rc.Name
 					if len(matrixes) > 1 {
 						rc.Name = fmt.Sprintf("%s-%d", rc.Name, i+1)
@@ -315,7 +332,7 @@ func handleFailure(plan *model.Plan) common.Executor {
 	}
 }
 
-func (runner *runnerImpl) newRunContext(ctx context.Context, run *model.Run, matrix map[string]any) *RunContext {
+func (runner *runnerImpl) newRunContext(ctx context.Context, run *model.Run, matrix map[string]any) (*RunContext, error) {
 	rc := &RunContext{
 		Config:      runner.config,
 		Run:         run,
@@ -324,15 +341,18 @@ func (runner *runnerImpl) newRunContext(ctx context.Context, run *model.Run, mat
 		Matrix:      matrix,
 		caller:      runner.caller,
 	}
+	if err := rc.resolveWorkflowCall(ctx); err != nil {
+		return nil, err
+	}
 	rc.ExprEval = rc.NewExpressionEvaluator(ctx)
-	rc.Name = rc.maskSecrets(rc.ExprEval.Interpolate(ctx, run.String()))
+	rc.Name = rc.maskSecrets(rc.ExprEval.InterpolateName(ctx, run.String()))
 	// Snapshot the job's pristine output expressions now, before any matrix combo runs and
 	// rewrites the shared Job.Outputs (see interpolateOutputs).
 	if job := run.Job(); job != nil {
 		rc.outputTemplate = maps.Clone(job.Outputs)
 	}
 
-	return rc
+	return rc, nil
 }
 
 // For Gitea

act/runner/step.go

@@ -11,6 +11,7 @@ import (
 	"path"
 	"strconv"
 	"strings"
+	"sync"
 	"time"
 
 	"gitea.com/gitea/runner/act/common"
@@ -82,9 +83,11 @@ func runStepExecutor(step step, stage stepStage, executor common.Executor) commo
 			rc.StepResults[rc.CurrentStep] = stepResult
 		}
 
-		setupEnv(ctx, step)
-
-		runStep, err := isStepEnabled(ctx, ifExpression, step, stage)
+		err := setupEnv(ctx, step)
+		var runStep bool
+		if err == nil {
+			runStep, err = isStepEnabled(ctx, ifExpression, step, stage)
+		}
 		if err != nil {
 			stepResult.Conclusion = model.StepStatusFailure
 			stepResult.Outcome = model.StepStatusFailure
@@ -99,7 +102,7 @@ func runStepExecutor(step step, stage stepStage, executor common.Executor) commo
 			return nil
 		}
 
-		stepString := rc.ExprEval.Interpolate(ctx, stepModel.String())
+		stepString := rc.ExprEval.InterpolateName(ctx, stepModel.String())
 		if strings.Contains(stepString, "::add-mask::") {
 			stepString = "add-mask command"
 		}
@@ -221,8 +224,10 @@ func runStepExecutor(step step, stage stepStage, executor common.Executor) commo
 }
 
 func evaluateStepTimeout(ctx context.Context, exprEval *expressionEvaluator, stepModel *model.Step) (context.Context, context.CancelFunc) {
-	timeout := exprEval.Interpolate(ctx, stepModel.TimeoutMinutes)
-	if timeout != "" {
+	timeout, err := exprEval.Interpolate(ctx, stepModel.TimeoutMinutes)
+	if err != nil {
+		common.Logger(ctx).Errorf("An error occurred when attempting to determine the step timeout: %s", err)
+	} else if timeout != "" {
 		if timeOutMinutes, err := strconv.ParseInt(timeout, 10, 64); err == nil && timeOutMinutes > 0 {
 			return context.WithTimeout(ctx, time.Duration(timeOutMinutes)*time.Minute)
 		}
@@ -230,27 +235,33 @@ func evaluateStepTimeout(ctx context.Context, exprEval *expressionEvaluator, ste
 	return ctx, func() {}
 }
 
-func setupEnv(ctx context.Context, step step) {
+func setupEnv(ctx context.Context, step step) error {
 	rc := step.getRunContext()
 
 	mergeEnv(ctx, step)
 	// merge step env last, since it should not be overwritten
 	mergeIntoMap(step, step.getEnv(), step.getStepModel().GetEnv())
 
+	var err error
 	exprEval := rc.NewExpressionEvaluator(ctx)
 	for k, v := range *step.getEnv() {
 		if !strings.HasPrefix(k, "INPUT_") {
-			(*step.getEnv())[k] = exprEval.Interpolate(ctx, v)
+			if (*step.getEnv())[k], err = exprEval.Interpolate(ctx, v); err != nil {
+				return fmt.Errorf("unable to interpolate env %s: %w", k, err)
+			}
 		}
 	}
 	// after we have an evaluated step context, update the expressions evaluator with a new env context
 	// you can use step level env in the with property of a uses construct
-	exprEval = rc.NewExpressionEvaluatorWithEnv(ctx, *step.getEnv())
+	inputEval := sync.OnceValue(func() *expressionEvaluator { return rc.NewExpressionEvaluatorWithEnv(ctx, *step.getEnv()) })
 	for k, v := range *step.getEnv() {
 		if strings.HasPrefix(k, "INPUT_") {
-			(*step.getEnv())[k] = exprEval.Interpolate(ctx, v)
+			if (*step.getEnv())[k], err = inputEval().Interpolate(ctx, v); err != nil {
+				return fmt.Errorf("unable to interpolate env %s: %w", k, err)
+			}
 		}
 	}
+	return nil
 }
 
 func mergeEnv(ctx context.Context, step step) {

act/runner/step_action_local.go

@@ -122,15 +122,19 @@ func (sal *stepActionLocal) getActionModel() *model.Action {
 	return sal.action
 }
 
-func (sal *stepActionLocal) getCompositeRunContext(ctx context.Context) *RunContext {
+func (sal *stepActionLocal) getCompositeRunContext(ctx context.Context) (*RunContext, error) {
 	if sal.compositeRunContext == nil {
 		actionDir := filepath.Join(sal.RunContext.Config.Workdir, sal.Step.Uses)
 		_, containerActionDir := getContainerActionPaths(sal.getStepModel(), actionDir, sal.RunContext)
 
-		sal.compositeRunContext = newCompositeRunContext(ctx, sal.RunContext, sal, containerActionDir)
-		sal.compositeSteps = sal.compositeRunContext.compositeExecutor(sal.action)
+		compositeRunContext, err := newCompositeRunContext(ctx, sal.RunContext, sal, containerActionDir)
+		if err != nil {
+			return nil, err
+		}
+		sal.compositeRunContext = compositeRunContext
+		sal.compositeSteps = compositeRunContext.compositeExecutor(sal.action)
 	}
-	return sal.compositeRunContext
+	return sal.compositeRunContext, nil
 }
 
 func (sal *stepActionLocal) getCompositeSteps() *compositeSteps {

act/runner/step_action_remote.go

@@ -51,7 +51,11 @@ func (sar *stepActionRemote) prepareActionExecutor() common.Executor {
 		// Since actions can specify the download source via a url prefix.
 		// The prefix may contain some sensitive information that needs to be stored in secrets,
 		// so we need to interpolate the expression value for uses first.
-		sar.Step.Uses = sar.RunContext.NewExpressionEvaluator(ctx).Interpolate(ctx, sar.Step.Uses)
+		uses, err := sar.RunContext.NewExpressionEvaluator(ctx).Interpolate(ctx, sar.Step.Uses)
+		if err != nil {
+			return fmt.Errorf("unable to interpolate uses: %w", err)
+		}
+		sar.Step.Uses = uses
 
 		github := sar.getGithubContext(ctx) // read before remoteAction is set, so `$/` resolves against the enclosing action
 		if strings.HasPrefix(sar.Step.Uses, selfRepoPrefix) {
@@ -160,8 +164,11 @@ func (sar *stepActionRemote) main() common.Executor {
 					common.Logger(ctx).Debugf("Skipping local actions/checkout because you bound your workspace")
 					return nil
 				}
-				eval := sar.RunContext.NewExpressionEvaluator(ctx)
-				copyToPath := path.Join(sar.RunContext.JobContainer.ToContainerPath(sar.RunContext.Config.Workdir), eval.Interpolate(ctx, sar.Step.With["path"]))
+				checkoutPath, err := sar.RunContext.NewExpressionEvaluator(ctx).Interpolate(ctx, sar.Step.With["path"])
+				if err != nil {
+					return fmt.Errorf("unable to interpolate with.path: %w", err)
+				}
+				copyToPath := path.Join(sar.RunContext.JobContainer.ToContainerPath(sar.RunContext.Config.Workdir), checkoutPath)
 				return sar.RunContext.JobContainer.CopyDir(copyToPath, sar.RunContext.Config.Workdir+string(filepath.Separator)+".", sar.RunContext.Config.UseGitIgnore)(ctx)
 			}
 
@@ -229,14 +236,18 @@ func (sar *stepActionRemote) getActionModel() *model.Action {
 	return sar.action
 }
 
-func (sar *stepActionRemote) getCompositeRunContext(ctx context.Context) *RunContext {
+func (sar *stepActionRemote) getCompositeRunContext(ctx context.Context) (*RunContext, error) {
 	if sar.compositeRunContext == nil {
 		actionDir := sar.actionDir()
 		actionLocation := path.Join(actionDir, sar.remoteAction.Path)
 		_, containerActionDir := getContainerActionPaths(sar.getStepModel(), actionLocation, sar.RunContext)
 
-		sar.compositeRunContext = newCompositeRunContext(ctx, sar.RunContext, sar, containerActionDir)
-		sar.compositeSteps = sar.compositeRunContext.compositeExecutor(sar.action)
+		compositeRunContext, err := newCompositeRunContext(ctx, sar.RunContext, sar, containerActionDir)
+		if err != nil {
+			return nil, err
+		}
+		sar.compositeRunContext = compositeRunContext
+		sar.compositeSteps = compositeRunContext.compositeExecutor(sar.action)
 	} else {
 		// Re-evaluate environment here. For remote actions the environment
 		// need to be re-created for every stage (pre, main, post) as there
@@ -244,11 +255,14 @@ func (sar *stepActionRemote) getCompositeRunContext(ctx context.Context) *RunCon
 		// stages are executed. (e.g. the output of another action is the
 		// input for this action during the main stage, but the env
 		// was already created during the pre stage)
-		env := evaluateCompositeInputAndEnv(ctx, sar.RunContext, sar)
+		env, err := evaluateCompositeInputAndEnv(ctx, sar.RunContext, sar)
+		if err != nil {
+			return nil, err
+		}
 		sar.compositeRunContext.setCompositeActionEnv(env)
 		sar.compositeRunContext.ExtraPath = sar.RunContext.ExtraPath
 	}
-	return sar.compositeRunContext
+	return sar.compositeRunContext, nil
 }
 
 func (sar *stepActionRemote) getCompositeSteps() *compositeSteps {

act/runner/step_action_remote_test.go

@@ -254,7 +254,8 @@ func TestStepActionRemote(t *testing.T) {
 
 		for _, value := range []string{"first", "second"} {
 			step.env["INPUT_SHARED"] = value
-			composite := step.getCompositeRunContext(t.Context())
+			composite, err := step.getCompositeRunContext(t.Context())
+			require.NoError(t, err)
 			assert.Equal(t, map[string]any{"shared": value}, composite.actionInputs)
 			assert.NotContains(t, composite.Env, "INPUT_SHARED")
 		}

act/runner/step_docker.go

@@ -6,6 +6,7 @@ package runner
 
 import (
 	"context"
+	"fmt"
 	"strings"
 
 	"gitea.com/gitea/runner/act/common"
@@ -58,17 +59,28 @@ func (sd *stepDocker) runUsesContainer() common.Executor {
 	return func(ctx context.Context) error {
 		image := strings.TrimPrefix(step.Uses, "docker://")
 		eval := rc.NewExpressionEvaluator(ctx)
-		cmd, err := shellquote.Split(eval.Interpolate(ctx, step.With["args"]))
+		args, err := eval.Interpolate(ctx, step.With["args"])
+		if err != nil {
+			return fmt.Errorf("unable to interpolate with.args: %w", err)
+		}
+		cmd, err := shellquote.Split(args)
 		if err != nil {
 			return err
 		}
 
 		var entrypoint []string
-		if entry := eval.Interpolate(ctx, step.With["entrypoint"]); entry != "" {
+		entry, err := eval.Interpolate(ctx, step.With["entrypoint"])
+		if err != nil {
+			return fmt.Errorf("unable to interpolate with.entrypoint: %w", err)
+		}
+		if entry != "" {
 			entrypoint = []string{entry}
 		}
 
-		stepContainer := newStepContainer(ctx, sd, image, cmd, entrypoint, "")
+		stepContainer, err := newStepContainer(ctx, sd, image, cmd, entrypoint, "")
+		if err != nil {
+			return err
+		}
 
 		return common.NewPipelineExecutor(
 			stepContainer.Pull(rc.Config.ForcePull),

act/runner/step_docker_test.go

@@ -16,6 +16,7 @@ import (
 	"gitea.dev/actionslib/pkg/model"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/mock"
+	"github.com/stretchr/testify/require"
 )
 
 func TestStepDockerMain(t *testing.T) {
@@ -144,7 +145,7 @@ func TestStepDockerNewStepContainerAllocatePTY(t *testing.T) {
 			}
 			sd.RunContext.ExprEval = sd.RunContext.NewExpressionEvaluator(ctx)
 
-			_ = newStepContainer(ctx, sd, "node:14", []string{"echo", "hi"}, nil, "")
+			_, _ = newStepContainer(ctx, sd, "node:14", []string{"echo", "hi"}, nil, "")
 			assert.Equal(t, tc.allocPTY, captured.AllocatePTY)
 		})
 	}
@@ -210,10 +211,10 @@ func TestStepDockerNewStepContainerNetworkMode(t *testing.T) {
 			}
 			sd.RunContext.ExprEval = sd.RunContext.NewExpressionEvaluator(ctx)
 
-			assert.Equal(t, tc.expectDefault, sd.RunContext.IsHostEnv(ctx),
-				"IsHostEnv mismatch for platform %q", tc.platform)
+			require.NoError(t, sd.RunContext.resolvePlatformImage(ctx))
+			assert.Equal(t, tc.expectDefault, sd.RunContext.IsHostEnv(), "IsHostEnv mismatch for platform %q", tc.platform)
 
-			_ = newStepContainer(ctx, sd, "alpine:3.20", []string{"echo", "hello"}, nil, "")
+			_, _ = newStepContainer(ctx, sd, "alpine:3.20", []string{"echo", "hello"}, nil, "")
 
 			if tc.expectDefault {
 				assert.Equal(t, "default", captured.NetworkMode,

act/runner/step_run.go

@@ -254,12 +254,21 @@ func getScriptName(rc *RunContext, step *model.Step) string {
 // OCI runtime exec failed: exec failed: container_linux.go:380: starting container process caused: exec: "${{": executable file not found in $PATH: unknown
 func (sr *stepRun) setupShellCommand(ctx context.Context) (name, script string, err error) {
 	logger := common.Logger(ctx)
-	implicitShell := sr.setupShell(ctx)
-	sr.setupWorkingDirectory(ctx)
+	eval := sr.RunContext.NewStepExpressionEvaluator(ctx, sr)
+	implicitShell, err := sr.setupShell(ctx, eval)
+	if err != nil {
+		return "", "", err
+	}
+	if err := sr.setupWorkingDirectory(ctx, eval); err != nil {
+		return "", "", err
+	}
 
 	step := sr.Step
 
-	script = sr.RunContext.NewStepExpressionEvaluator(ctx, sr).Interpolate(ctx, step.Run)
+	script, err = eval.Interpolate(ctx, step.Run)
+	if err != nil {
+		return "", "", fmt.Errorf("unable to interpolate the run script: %w", err)
+	}
 	sr.interpolatedScript = script
 
 	// GitHub matches the built-in names case-insensitively, so `shell: PWSH` is valid
@@ -313,19 +322,21 @@ func (sr *stepRun) setupShellCommand(ctx context.Context) (name, script string,
 	return name, script, err
 }
 
-func (sr *stepRun) setupShell(ctx context.Context) bool {
+func (sr *stepRun) setupShell(ctx context.Context, eval *expressionEvaluator) (bool, error) {
 	rc := sr.RunContext
 	step := sr.Step
 
-	if step.Shell == "" {
-		step.Shell = rc.Run.Job().Defaults.Run.Shell
+	shell, err := eval.Interpolate(ctx, step.Shell)
+	if err != nil {
+		return false, fmt.Errorf("unable to interpolate the shell: %w", err)
 	}
-
-	step.Shell = rc.NewStepExpressionEvaluator(ctx, sr).Interpolate(ctx, step.Shell)
-
-	if step.Shell == "" {
-		step.Shell = rc.Run.Workflow.Defaults.Run.Shell
+	if shell == "" {
+		shell = rc.jobRunDefaults.Shell
 	}
+	if shell == "" {
+		shell = rc.Run.Workflow.Defaults.Run.Shell
+	}
+	step.Shell = shell
 
 	implicitShell := step.Shell == ""
 	if implicitShell {
@@ -349,7 +360,7 @@ func (sr *stepRun) setupShell(ctx context.Context) bool {
 			}
 		}
 	}
-	return implicitShell
+	return implicitShell, nil
 }
 
 // containerHasBash probes once per job, else every implicit-shell step pays for an exec.
@@ -364,23 +375,19 @@ func (rc *RunContext) containerHasBash(ctx context.Context, env map[string]strin
 	return *top.hasBash
 }
 
-func (sr *stepRun) setupWorkingDirectory(ctx context.Context) {
+func (sr *stepRun) setupWorkingDirectory(ctx context.Context, eval *expressionEvaluator) error {
 	rc := sr.RunContext
-	step := sr.Step
-	var workingdirectory string
-
-	if step.WorkingDirectory == "" {
-		workingdirectory = rc.Run.Job().Defaults.Run.WorkingDirectory
-	} else {
-		workingdirectory = step.WorkingDirectory
+	workingdirectory, err := eval.Interpolate(ctx, sr.Step.WorkingDirectory)
+	if err != nil {
+		return fmt.Errorf("unable to interpolate the working directory: %w", err)
 	}
-
-	// jobs can receive context values, so we interpolate
-	workingdirectory = rc.NewStepExpressionEvaluator(ctx, sr).Interpolate(ctx, workingdirectory)
-
-	// but top level keys in workflow file like `defaults` or `env` can't
+	if workingdirectory == "" {
+		workingdirectory = rc.jobRunDefaults.WorkingDirectory
+	}
+	// top level keys in workflow file like `defaults` or `env` can't hold expressions
 	if workingdirectory == "" {
 		workingdirectory = rc.Run.Workflow.Defaults.Run.WorkingDirectory
 	}
 	sr.WorkingDirectory = workingdirectory
+	return nil
 }

act/runner/step_run_test.go

@@ -6,6 +6,7 @@ package runner
 
 import (
 	"bytes"
+	"cmp"
 	"context"
 	"io"
 	"os"
@@ -42,17 +43,12 @@ func TestStepRun(t *testing.T) {
 				JobID: "1",
 				Workflow: &model.Workflow{
 					Jobs: map[string]*model.Job{
-						"1": {
-							Defaults: model.Defaults{
-								Run: model.RunDefaults{
-									Shell: "bash",
-								},
-							},
-						},
+						"1": {},
 					},
 				},
 			},
-			JobContainer: cm,
+			JobContainer:   cm,
+			jobRunDefaults: model.RunDefaults{Shell: "bash"},
 		},
 		Step: &model.Step{
 			ID:               "1",
@@ -84,13 +80,13 @@ func TestStepRun(t *testing.T) {
 
 func TestStepRunShellParity(t *testing.T) {
 	tests := []struct {
-		name, shell, workingDir string
-		env                     map[string]string
-		host                    bool
-		probeErr                error
-		wantExt                 string
-		wantCmd                 []string
-		wantErr                 string
+		name, run, shell, workingDir string
+		env                          map[string]string
+		host                         bool
+		probeErr                     error
+		wantExt                      string
+		wantCmd                      []string
+		wantErr                      string
 	}{
 		{
 			name:    "implicit host bash",
@@ -130,6 +126,21 @@ func TestStepRunShellParity(t *testing.T) {
 			wantExt:    ".py",
 			wantCmd:    []string{"python", "/var/run/act/workflow/1.py"},
 		},
+		{
+			name:    "run expression without a context",
+			run:     "echo ${{ COMMIT_SHA }}",
+			wantErr: "unable to interpolate the run script:",
+		},
+		{
+			name:    "shell expression without a context",
+			shell:   "${{ SHELL }}",
+			wantErr: "unable to interpolate the shell:",
+		},
+		{
+			name:       "working directory expression without a context",
+			workingDir: "${{ DIR }}",
+			wantErr:    "unable to interpolate the working directory:",
+		},
 	}
 
 	for _, test := range tests {
@@ -156,13 +167,13 @@ func TestStepRunShellParity(t *testing.T) {
 					Run:          &model.Run{JobID: "1", Workflow: &model.Workflow{Jobs: map[string]*model.Job{"1": {}}}},
 					JobContainer: jobContainer,
 				},
-				Step: &model.Step{ID: "1", Run: "echo hi", Shell: test.shell, WorkingDirectory: test.workingDir},
+				Step: &model.Step{ID: "1", Run: cmp.Or(test.run, "echo hi"), Shell: test.shell, WorkingDirectory: test.workingDir},
 				env:  test.env,
 			}
 
 			name, script, err := sr.setupShellCommand(t.Context())
 			if test.wantErr != "" {
-				require.EqualError(t, err, test.wantErr)
+				require.ErrorContains(t, err, test.wantErr)
 				return
 			}
 			require.NoError(t, err)

act/runner/step_test.go

@@ -160,7 +160,7 @@ func TestSetupEnv(t *testing.T) {
 	sm.On("getStepModel").Return(step)
 	sm.On("getEnv").Return(&env)
 
-	setupEnv(context.Background(), sm)
+	require.NoError(t, setupEnv(context.Background(), sm))
 
 	// These are commit or system specific
 	delete(env, "GITHUB_REF")

docs/macos-vm-executor.md

@@ -0,0 +1,93 @@
+# macOS VM executor
+
+The runner can execute a job in an ephemeral macOS VM by registering a
+`macos-vm` label:
+
+```yaml
+runner:
+  labels:
+    - macos-latest:macos-vm://registry.example.com/macos-15.2-xcode-26.1
+```
+
+The VM is created and managed by `runner-executor-macos`, a dedicated Swift
+binary built on Apple Virtualization.framework. The source VM must include the
+runner guest agent.
+
+## Configuration
+
+```yaml
+macos_vm:
+  executor_path: runner-executor-macos
+  workdir_parent: /Users/admin/runner
+  cpu: 0
+  memory: 0
+  boot_timeout: 5m
+```
+
+`workdir_parent` is the guest directory under which job workspaces are created.
+`executor_path` is the binary to invoke; an empty value uses PATH lookup.
+
+## Executor CLI
+
+The runner uses a narrow, runner-oriented command set:
+
+```text
+runner-executor-macos provision <image> <name> [--cpu N] [--memory MB]
+runner-executor-macos start <name> [--no-graphics]
+runner-executor-macos exec <name> [--stdin] <argv...>
+runner-executor-macos stop <name> [--timeout N]
+runner-executor-macos destroy <name>
+runner-executor-macos list --format json
+runner-executor-macos version
+```
+
+`list --format json` returns:
+
+```json
+[
+  {
+    "name": "GITEA-MACOS-VM-<runner-uuid>-...",
+    "state": "stopped",
+    "running": false,
+    "accessed_at": "2026-09-05T12:00:00Z"
+  }
+]
+```
+
+## Integration test
+
+The end-to-end test is opt-in because it provisions and boots a real VM:
+
+```bash
+MACOS_VM_TEST_IMAGE=/path/or/reference \
+  go test -tags macos_vm_integration ./act/container -run '^TestMacOSVMEnvironmentIntegration$' -v
+```
+
+The test skips when `MACOS_VM_TEST_IMAGE` is unset.
+
+## Orphaned VM cleanup
+
+Job VM names start with `GITEA-MACOS-VM-<runner-uuid>-`. While the runner is
+idle, it lists local VMs and destroys the non-running ones whose name has this
+runner's UUID and whose access time is older than
+`runner.workdir_cleanup_age`.
+
+## Service containers
+
+Service containers are intentionally rejected for macOS VM jobs today. Docker
+service containers live on a Docker network and are reached by workflow service
+id, which a macOS VM cannot resolve.
+
+Possible future designs:
+
+1. **Host-published Docker services + guest host mapping** — publish each
+   service port on the runner host and inject `<service-id> -> <host-ip>` into
+   the VM through the guest agent.
+2. **macOS VM services** — run each service as another VM; this requires
+   service discovery and is much heavier than Docker containers.
+3. **Environment-based discovery** — require workflows to read service
+   addresses from env vars instead of hostnames, breaking GitHub Actions
+   compatibility.
+
+Option 1 is the most compatible direction once the guest agent and host network
+configuration are stable.

go.mod

@@ -102,6 +102,6 @@ require (
 	go.opentelemetry.io/otel/metric v1.45.0 // indirect
 	go.opentelemetry.io/otel/trace v1.45.0 // indirect
 	go.yaml.in/yaml/v3 v3.0.5 // indirect
-	golang.org/x/crypto v0.55.0 // indirect
+	golang.org/x/crypto v0.56.0 // indirect
 	gopkg.in/warnings.v0 v0.1.2 // indirect
 )

go.sum

@@ -234,8 +234,8 @@ go.yaml.in/yaml/v3 v3.0.5/go.mod h1:HVTZu1O7/Vkt2N+BFy8Zza+lnLsABggaTM2ZpNIGuKg=
 go.yaml.in/yaml/v4 v4.0.0-rc.3 h1:3h1fjsh1CTAPjW7q/EMe+C8shx5d8ctzZTrLcs/j8Go=
 go.yaml.in/yaml/v4 v4.0.0-rc.3/go.mod h1:aZqd9kCMsGL7AuUv/m/PvWLdg5sjJsZ4oHDEnfPPfY0=
 golang.org/x/crypto v0.0.0-20220622213112-05595931fe9d/go.mod h1:IxCIyHEi3zRg3s0A5j5BB6A9Jmi73HwBIUl50j+osU4=
-golang.org/x/crypto v0.55.0 h1:+KWHjbgOaAQ66dh/YlkZKHlz9ZUlq61AFirAR9ntP8M=
-golang.org/x/crypto v0.55.0/go.mod h1:uq0V9dE/fzQuJtbnL+2EhWOE63vo164FY8xqEnV9xis=
+golang.org/x/crypto v0.56.0 h1:GUh5Ii4J5jtcseSMiRqr1jXCNHoxjeV9Fmekc2oLy6Y=
+golang.org/x/crypto v0.56.0/go.mod h1:OMW5y6CY9l38uPLmxU6l6pwcXp1obtLo3e6gT7gQR2I=
 golang.org/x/exp v0.0.0-20260410095643-746e56fc9e2f h1:W3F4c+6OLc6H2lb//N1q4WpJkhzJCK5J6kUi1NTVXfM=
 golang.org/x/exp v0.0.0-20260410095643-746e56fc9e2f/go.mod h1:J1xhfL/vlindoeF/aINzNzt2Bket5bjo9sdOYzOsU80=
 golang.org/x/net v0.0.0-20211112202133-69e39bad7dc2/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=

internal/app/cmd/register_test.go

@@ -62,6 +62,7 @@ func TestRegisterInputsValidate(t *testing.T) {
 
 func TestValidateLabels(t *testing.T) {
 	require.NoError(t, validateLabels([]string{"ubuntu:host", "ubuntu:docker://node:18"}))
+	require.NoError(t, validateLabels([]string{"macos-latest:macos-vm://ghcr.io/cirruslabs/macos-sonoma-base:latest"}))
 	// a colon that is not a supported schema is part of the label name
 	require.NoError(t, validateLabels([]string{"pool:e57e18d4-10d4-406f-93bf-60f127221bdd"}))
 	require.Error(t, validateLabels([]string{"ubuntu:host", ""}))

internal/app/run/runner.go

@@ -144,6 +144,9 @@ func (r *Runner) Close() error {
 // removeOrphanNetworks is a variable so tests can substitute one that needs no Docker daemon.
 var removeOrphanNetworks = container.RemoveOrphanNetworks
 
+// removeOrphanMacOSVMs is a variable so tests can substitute one that needs no macOS VM executor.
+var removeOrphanMacOSVMs = container.CleanupOrphanMacOSVMs
+
 // OnIdle performs lightweight maintenance during polling idle windows.
 // It runs synchronously on the poller goroutine; shouldRunIdleCleanup
 // throttles invocations to runner.idle_cleanup_interval so the impact on
@@ -166,6 +169,7 @@ func (r *Runner) OnIdle(ctx context.Context) {
 		r.cleanupStaleDirs(ctx, hostRoot, isHostScratchDir)
 	}
 	r.cleanupOrphanNetworks(ctx)
+	r.cleanupOrphanMacOSVMs(ctx)
 }
 
 // cleanupOrphanNetworks reclaims the per-job networks of jobs this runner did not live to
@@ -182,6 +186,16 @@ func (r *Runner) cleanupOrphanNetworks(ctx context.Context) {
 	}
 }
 
+func (r *Runner) cleanupOrphanMacOSVMs(ctx context.Context) {
+	if r.uuid == "" || !r.labels.RequireMacOSVM() || r.cfg.Runner.WorkdirCleanupAge <= 0 {
+		return
+	}
+	cutoff := r.now().Add(-r.cfg.Runner.WorkdirCleanupAge)
+	if err := removeOrphanMacOSVMs(ctx, r.cfg.MacOSVM.ExecutorPath, r.uuid, cutoff); err != nil {
+		log.Warnf("failed to clean up macOS VMs left behind by earlier jobs: %v", err)
+	}
+}
+
 func (r *Runner) shouldRunIdleCleanup() bool {
 	if r.cfg.Runner.WorkdirCleanupAge <= 0 || r.cfg.Runner.IdleCleanupInterval <= 0 {
 		return false
@@ -548,8 +562,16 @@ func (r *Runner) run(ctx context.Context, task *runnerv1.Task, reporter *report.
 		Vars:                              task.Vars,
 		ValidVolumes:                      r.cfg.Container.ValidVolumes,
 		SharedToolCache:                   r.cfg.Runner.ToolCacheMode == config.ToolCacheModeShared,
-		InsecureSkipTLS:                   r.cfg.Runner.Insecure,
-		RunnerName:                        r.name,
+		MacOSVM: runner.MacOSVMConfig{
+			ExecutorPath:  r.cfg.MacOSVM.ExecutorPath,
+			WorkdirParent: r.cfg.MacOSVM.WorkdirParent,
+			CPU:           r.cfg.MacOSVM.CPU,
+			Memory:        r.cfg.MacOSVM.Memory,
+			BootTimeout:   r.cfg.MacOSVM.BootTimeout,
+		},
+		InsecureSkipTLS: r.cfg.Runner.Insecure,
+		RunnerUUID:      r.uuid,
+		RunnerName:      r.name,
 	}
 
 	rr, err := runner.New(runnerConfig)

internal/app/run/runner_idle_cleanup_test.go

@@ -12,6 +12,7 @@ import (
 	"time"
 
 	"gitea.com/gitea/runner/internal/pkg/config"
+	"gitea.com/gitea/runner/internal/pkg/labels"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -331,3 +332,37 @@ func TestRunnerOnIdleRemovesOrphanNetworks(t *testing.T) {
 	hostOnly.OnIdle(context.Background())
 	assert.Equal(t, []string{"runner-1"}, swept)
 }
+
+func TestRunnerOnIdleRemovesOrphanMacOSVMs(t *testing.T) {
+	now := time.Date(2026, time.April, 29, 20, 0, 0, 0, time.UTC)
+	cfg := &config.Config{
+		Runner: config.Runner{
+			WorkdirCleanupAge:   24 * time.Hour,
+			IdleCleanupInterval: time.Minute,
+		},
+	}
+	macOSVMLabel, err := labels.Parse("macos-latest:macos-vm://ghcr.io/cirruslabs/macos-sonoma-base:latest")
+	require.NoError(t, err)
+
+	var swept []string
+	var sweptCutoff time.Time
+	origRemoveOrphanMacOSVMs := removeOrphanMacOSVMs
+	removeOrphanMacOSVMs = func(_ context.Context, _, runnerUUID string, accessedBefore time.Time) error {
+		swept = append(swept, runnerUUID)
+		sweptCutoff = accessedBefore
+		return nil
+	}
+	t.Cleanup(func() { removeOrphanMacOSVMs = origRemoveOrphanMacOSVMs })
+
+	r := &Runner{uuid: "runner-1", cfg: cfg, labels: labels.Labels{macOSVMLabel}, now: func() time.Time { return now }}
+	r.OnIdle(context.Background())
+	assert.Equal(t, []string{"runner-1"}, swept)
+	assert.Equal(t, now.Add(-24*time.Hour), sweptCutoff)
+
+	// a docker-only runner has no macOS VMs to sweep
+	dockerLabel, err := labels.Parse("ubuntu:docker://node:18")
+	require.NoError(t, err)
+	dockerOnly := &Runner{uuid: "runner-2", cfg: &config.Config{Runner: cfg.Runner}, labels: labels.Labels{dockerLabel}, now: func() time.Time { return now }}
+	dockerOnly.OnIdle(context.Background())
+	assert.Equal(t, []string{"runner-1"}, swept)
+}

internal/pkg/config/config.example.yaml

@@ -92,7 +92,8 @@ runner:
   # at the price of the stock artifact actions refusing and the cache client keeping to v1.
   #patch_actions: true
   # The labels of a runner are used to determine which jobs the runner can run, and how to run them.
-  # Like: "macos-arm64:host" or "ubuntu-latest:docker://docker.gitea.com/runner-images:ubuntu-latest"
+  # Like: "macos-arm64:host", "ubuntu-latest:docker://docker.gitea.com/runner-images:ubuntu-latest",
+  # or "macos-latest:macos-vm://ghcr.io/cirruslabs/macos-sonoma-base:latest"
   # Find more images provided by Gitea at https://gitea.com/gitea/runner-images .
   # If it's empty when registering, it will ask for inputting labels.
   # If it's empty when execute `daemon`, will use labels in `.runner` file.
@@ -260,7 +261,7 @@ container:
   # This is required for Docker-in-Docker (DinD) setups when jobs use docker compose
   # with bind mounts (e.g., ".:/app"), as volume-based workspaces are not accessible
   # from the DinD daemon's filesystem. When enabled, ensure the workspace parent
-  # directory is also mounted into the runner container and listed in valid_volumes.
+  # directory is also mounted into the runner container.
   #bind_workdir: false
   # How long a job waits for a service container that declares a healthcheck to become
   # healthy. A negative value (e.g. -1s) starts the steps without waiting.
@@ -271,6 +272,19 @@ host:
   # If it's empty, $HOME/.cache/act/ will be used.
   #workdir_parent:
 
+macos_vm:
+  # Path to the runner-executor-macos binary. Empty uses PATH lookup.
+  #executor_path: runner-executor-macos
+  # The guest directory under which the job workspace is created. The VM must run
+  # as a user that can write there.
+  #workdir_parent: /Users/admin/runner
+  # Number of virtual CPUs. Omit or set to 0 to keep the image default.
+  #cpu: 0
+  # VM memory in megabytes. Omit or set to 0 to keep the image default.
+  #memory: 0
+  # How long to wait for the VM to become ready after it starts.
+  #boot_timeout: 5m
+
 # Optional local task-admission checks. Disabled by default. When enabled, low
 # disk space or a failing script pauses new task fetching; existing jobs continue.
 # No health checks run while any job is active; the last result is reused until idle.

internal/pkg/config/config.go

@@ -179,6 +179,15 @@ type Host struct {
 	WorkdirParent string `yaml:"workdir_parent"` // WorkdirParent specifies the parent directory for the host's working directory.
 }
 
+// MacOSVM represents the configuration for the macOS VM executor.
+type MacOSVM struct {
+	ExecutorPath  string        `yaml:"executor_path"`  // ExecutorPath is the runner-executor-macos binary to invoke.
+	WorkdirParent string        `yaml:"workdir_parent"` // WorkdirParent is the guest directory under which the job workspace is created.
+	CPU           int           `yaml:"cpu"`            // CPU is the number of virtual CPUs. Zero keeps the image default.
+	Memory        int           `yaml:"memory"`         // Memory is the VM memory in megabytes. Zero keeps the image default.
+	BootTimeout   time.Duration `yaml:"boot_timeout"`   // BootTimeout bounds how long to wait for the VM to become ready.
+}
+
 // Metrics represents the configuration for the Prometheus metrics endpoint.
 type Metrics struct {
 	Enabled        bool          `yaml:"enabled"`         // Enabled indicates whether the metrics endpoint is exposed.
@@ -203,6 +212,7 @@ type Config struct {
 	Cache       Cache       `yaml:"cache"`        // Cache represents the configuration for caching.
 	Container   Container   `yaml:"container"`    // Container represents the configuration for the container.
 	Host        Host        `yaml:"host"`         // Host represents the configuration for the host.
+	MacOSVM     MacOSVM     `yaml:"macos_vm"`     // MacOSVM represents the configuration for the macOS VM executor.
 	Metrics     Metrics     `yaml:"metrics"`      // Metrics represents the configuration for the Prometheus metrics endpoint.
 	HealthCheck HealthCheck `yaml:"health_check"` // HealthCheck controls opt-in local task-admission checks.
 }
@@ -300,6 +310,15 @@ func LoadDefault(file string) (*Config, error) {
 		}
 		cfg.Host.WorkdirParent = filepath.Join(home, ".cache", "act")
 	}
+	if cfg.MacOSVM.ExecutorPath == "" {
+		cfg.MacOSVM.ExecutorPath = "runner-executor-macos"
+	}
+	if cfg.MacOSVM.WorkdirParent == "" {
+		cfg.MacOSVM.WorkdirParent = "/Users/admin/runner"
+	}
+	if cfg.MacOSVM.BootTimeout <= 0 {
+		cfg.MacOSVM.BootTimeout = 5 * time.Minute
+	}
 	if cfg.Runner.FetchTimeout <= 0 {
 		cfg.Runner.FetchTimeout = 5 * time.Second
 	}

internal/pkg/config/config_test.go

@@ -67,6 +67,31 @@ func TestLoadDefault_DefaultsWorkdirCleanupAge(t *testing.T) {
 	assert.Equal(t, DefaultImage, cfg.Runner.DefaultImage)
 }
 
+func TestLoadDefault_MacOSVMDefaults(t *testing.T) {
+	cfg, err := LoadDefault("")
+	require.NoError(t, err)
+	assert.Equal(t, "runner-executor-macos", cfg.MacOSVM.ExecutorPath)
+	assert.Equal(t, "/Users/admin/runner", cfg.MacOSVM.WorkdirParent)
+	assert.Equal(t, 5*time.Minute, cfg.MacOSVM.BootTimeout)
+
+	path := filepath.Join(t.TempDir(), "config.yaml")
+	require.NoError(t, os.WriteFile(path, []byte(`
+macos_vm:
+  executor_path: /usr/local/bin/runner-executor-macos
+  workdir_parent: /Users/runner
+  cpu: 4
+  memory: 8192
+  boot_timeout: 3m
+`), 0o600))
+	cfg, err = LoadDefault(path)
+	require.NoError(t, err)
+	assert.Equal(t, "/usr/local/bin/runner-executor-macos", cfg.MacOSVM.ExecutorPath)
+	assert.Equal(t, "/Users/runner", cfg.MacOSVM.WorkdirParent)
+	assert.Equal(t, 4, cfg.MacOSVM.CPU)
+	assert.Equal(t, 8192, cfg.MacOSVM.Memory)
+	assert.Equal(t, 3*time.Minute, cfg.MacOSVM.BootTimeout)
+}
+
 func TestLoadDefault_HealthChecksAreOptIn(t *testing.T) {
 	cfg, err := LoadDefault("")
 	require.NoError(t, err)

internal/pkg/labels/labels.go

@@ -9,11 +9,15 @@ import (
 )
 
 const (
-	SchemeHost   = "host"
-	SchemeDocker = "docker"
+	SchemeHost    = "host"
+	SchemeDocker  = "docker"
+	SchemeMacOSVM = "macos-vm"
 
 	// SelfHostedPlatform is the platform marker act treats as "run on the host".
 	SelfHostedPlatform = "-self-hosted"
+
+	// MacOSVMSchemePrefix marks a platform image that act should run in a macOS VM.
+	MacOSVMSchemePrefix = "macos-vm://"
 )
 
 type Label struct {
@@ -42,7 +46,7 @@ func Parse(str string) (*Label, error) {
 	if len(splits) >= 3 {
 		label.Arg = splits[2]
 	}
-	if label.Schema != SchemeHost && label.Schema != SchemeDocker {
+	if label.Schema != SchemeHost && label.Schema != SchemeDocker && label.Schema != SchemeMacOSVM {
 		// Not a schema we know: the colon belongs to the label name itself.
 		return &Label{
 			Name:   str,
@@ -64,6 +68,15 @@ func (l Labels) RequireDocker() bool {
 	return false
 }
 
+func (l Labels) RequireMacOSVM() bool {
+	for _, label := range l {
+		if label.Schema == SchemeMacOSVM {
+			return true
+		}
+	}
+	return false
+}
+
 // PickPlatform returns the platform of the first runs-on entry this runner has a label for, or "".
 func (l Labels) PickPlatform(runsOn []string) string {
 	platforms := make(map[string]string, len(l))
@@ -72,10 +85,12 @@ func (l Labels) PickPlatform(runsOn []string) string {
 		case SchemeDocker:
 			// "//" will be ignored
 			platforms[label.Name] = strings.TrimPrefix(label.Arg, "//")
+		case SchemeMacOSVM:
+			platforms[label.Name] = MacOSVMSchemePrefix + strings.TrimPrefix(label.Arg, "//")
 		case SchemeHost:
 			platforms[label.Name] = SelfHostedPlatform
 		default:
-			// unreachable: Parse only produces host or docker schemas
+			// unreachable: Parse only produces host, docker, or macOS VM schemas
 			continue
 		}
 	}

internal/pkg/labels/labels_test.go

@@ -25,6 +25,15 @@ func TestParse(t *testing.T) {
 			},
 			wantErr: false,
 		},
+		{
+			args: "macos-latest:macos-vm://ghcr.io/cirruslabs/macos-sonoma-base:latest",
+			want: &Label{
+				Name:   "macos-latest",
+				Schema: "macos-vm",
+				Arg:    "//ghcr.io/cirruslabs/macos-sonoma-base:latest",
+			},
+			wantErr: false,
+		},
 		{
 			args: "ubuntu:host",
 			want: &Label{
@@ -103,6 +112,7 @@ func TestRequireDocker(t *testing.T) {
 		{"empty", nil, false},
 		{"only host", []string{"ubuntu:host", "self-hosted"}, false},
 		{"has docker", []string{"ubuntu:host", "ubuntu:docker://node:18"}, true},
+		{"macos-vm does not require docker", []string{"macos-latest:macos-vm://ghcr.io/cirruslabs/macos-sonoma-base:latest"}, false},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -111,10 +121,29 @@ func TestRequireDocker(t *testing.T) {
 	}
 }
 
+func TestRequireMacOSVM(t *testing.T) {
+	tests := []struct {
+		name string
+		strs []string
+		want bool
+	}{
+		{"empty", nil, false},
+		{"only host", []string{"ubuntu:host", "self-hosted"}, false},
+		{"only docker", []string{"ubuntu:docker://node:18"}, false},
+		{"has macos-vm", []string{"macos-latest:macos-vm://ghcr.io/cirruslabs/macos-sonoma-base:latest"}, true},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			require.Equal(t, tt.want, mustParse(t, tt.strs...).RequireMacOSVM())
+		})
+	}
+}
+
 func TestPickPlatform(t *testing.T) {
 	ls := mustParse(t,
 		"ubuntu:docker://node:18",
 		"self-hosted:host",
+		"macos-latest:macos-vm://ghcr.io/cirruslabs/macos-sonoma-base:latest",
 	)
 
 	tests := []struct {
@@ -124,6 +153,7 @@ func TestPickPlatform(t *testing.T) {
 	}{
 		{"docker strips leading slashes", []string{"ubuntu"}, "node:18"},
 		{"host maps to self-hosted marker", []string{"self-hosted"}, SelfHostedPlatform},
+		{"macos-vm prefixes platform marker", []string{"macos-latest"}, MacOSVMSchemePrefix + "ghcr.io/cirruslabs/macos-sonoma-base:latest"},
 		{"first match wins", []string{"self-hosted", "ubuntu"}, SelfHostedPlatform},
 		{"unknown label picks nothing", []string{"windows"}, ""},
 		{"no runsOn picks nothing", nil, ""},
@@ -145,12 +175,14 @@ func TestToStrings(t *testing.T) {
 	ls := mustParse(t,
 		"ubuntu:docker://node:18",
 		"self-hosted:host",
+		"macos-latest:macos-vm://ghcr.io/cirruslabs/macos-sonoma-base:latest",
 		"bare",
 		"pool:e57e18d4",
 	)
 	require.Equal(t, []string{
 		"ubuntu:docker://node:18",
 		"self-hosted:host",
+		"macos-latest:macos-vm://ghcr.io/cirruslabs/macos-sonoma-base:latest",
 		"bare:host",
 		"pool:e57e18d4",
 	}, ls.ToStrings())