fix: align common behaviour with GitHub's runner (#1413)

Closes differences from GitHub's runner that common workflows hit:

- `ACTIONS_STEP_DEBUG` set as a repository variable enables debug output as on GitHub, where a secret of the same name still takes precedence. `runner.debug` and `RUNNER_DEBUG` are now also set inside composite actions, which lost the secret.
- `github.env` and `github.path` hold the file-command paths instead of being empty, so `echo "A=1" >> "${{ github.env }}"` works.
- Remote composite actions only get a pre stage when they nest actions. That stage evaluated `with:` before earlier steps ran, so an input like `${{ fromJSON(steps.meta.outputs.json).v }}` failed the job.
- `ports` on a job container are published, they were ignored while service ports worked.
- Dockerfile action build output reaches the job log. It was logged at debug and dropped, so a failing `RUN` showed only the final error.
- Local Docker actions honor their `.dockerignore`, as `docker build` does.
- Cancelling or timing out a host-mode step sends SIGINT, then SIGTERM after 7.5 seconds and SIGKILL after 2.5 more, as GitHub's runner does, so `trap` handlers and shutdown hooks run.
- `.sh` job hooks fall back to `sh` where bash is missing, and `.ps1` hooks to `powershell` where pwsh is missing, as on GitHub.

_Written by Claude (Opus 5.5)._

Reviewed-on: https://gitea.com/gitea/runner/pulls/1413
Reviewed-by: bircni <[email protected]>
Co-authored-by: silverwind <[email protected]>

act/container/docker_logger.go

@@ -8,6 +8,7 @@ package container
 
 import (
 	"bufio"
+	"cmp"
 	"encoding/json/v2"
 	"errors"
 	"io"
@@ -26,10 +27,7 @@ type dockerMessage struct {
 	Progress string `json:"progress"`
 }
 
-func logDockerResponse(logger *logging.Logger, dockerResponse io.ReadCloser, isError bool) error {
-	if dockerResponse == nil {
-		return nil
-	}
+func logDockerResponse(logger *logging.Logger, dockerResponse io.ReadCloser, log func(string, ...any)) error {
 	defer dockerResponse.Close()
 
 	scanner := bufio.NewScanner(dockerResponse)
@@ -38,41 +36,28 @@ func logDockerResponse(logger *logging.Logger, dockerResponse io.ReadCloser, isE
 		line := scanner.Bytes()
 		var msg dockerMessage
 		if err := json.Unmarshal(line, &msg); err != nil {
-			writeLog(logger, false, "Unable to unmarshal line [%s] ==> %v", string(line), err)
+			logger.Debugf("Unable to unmarshal line [%s] ==> %v", string(line), err)
 			continue
 		}
 
-		if msg.Error != "" {
-			writeLog(logger, isError, "%s", msg.Error)
-			return errors.New(msg.Error)
-		}
-
-		if msg.ErrorDetail.Message != "" {
-			writeLog(logger, isError, "%s", msg.ErrorDetail.Message)
-			return errors.New(msg.ErrorDetail.Message)
+		if message := cmp.Or(msg.Error, msg.ErrorDetail.Message); message != "" {
+			log("%s", message)
+			return errors.New(message)
 		}
 
 		switch {
 		case msg.Status != "":
 			if msg.Progress != "" {
-				writeLog(logger, isError, "%s :: %s :: %s\n", msg.Status, msg.ID, msg.Progress)
+				log("%s :: %s :: %s\n", msg.Status, msg.ID, msg.Progress)
 			} else {
-				writeLog(logger, isError, "%s :: %s\n", msg.Status, msg.ID)
+				log("%s :: %s\n", msg.Status, msg.ID)
 			}
 		case msg.Stream != "":
-			writeLog(logger, isError, "%s", msg.Stream)
+			log("%s", msg.Stream)
 		default:
-			writeLog(logger, false, "Unable to handle line: %s", string(line))
+			logger.Debugf("Unable to handle line: %s", string(line))
 		}
 	}
 
 	return scanner.Err()
 }
-
-func writeLog(logger *logging.Logger, isError bool, format string, args ...any) {
-	if isError {
-		logger.Errorf(format, args...)
-	} else {
-		logger.Debugf(format, args...)
-	}
-}