fix: restore the caller's event and inputs in reusable workflow jobs (#1250)

Fixes https://github.com/go-gitea/gitea/issues/38705

Gitea side: https://github.com/go-gitea/gitea/pull/39452

Jobs of a called workflow currently see `gitea.event_name == "workflow_call"`, and their `gitea.event.inputs` is replaced by the caller's `with:`. On GitHub they keep the caller's event, and their `inputs` are the run's `workflow_dispatch` inputs overlaid with the caller's `with:`.

For compatibility with older runners, Gitea keeps sending that form and adds a `gitea_workflow_call` key with the original trigger event name and inputs of the run, and the `inputs` Gitea resolved for the job. When the key is present, the runner restores `gitea.event_name` and `gitea.event.inputs` from it, and uses the resolved `inputs` for the job's expressions and the setup log.

Without that key (older Gitea, or jobs outside called workflows), nothing changes.

Reviewed-on: https://gitea.com/gitea/runner/pulls/1250
Reviewed-by: bircni <[email protected]>
Reviewed-by: silverwind <[email protected]>
Co-authored-by: Zettat123 <[email protected]>

act/runner/expression_test.go

@@ -392,6 +392,28 @@ jobs:
 	})
 }
 
+func TestGetEvaluatorInputsResolvedByGitea(t *testing.T) {
+	wf, err := model.ReadWorkflow(strings.NewReader(`
+on:
+  workflow_call:
+    inputs:
+      name: {type: string, default: callee}
+  workflow_dispatch:
+    inputs:
+      name: {type: string}
+`))
+	require.NoError(t, err)
+	config := &Config{Workdir: ".", WorkflowCallInputs: map[string]any{"name": "caller", "target": "dispatch"}}
+	ghc := &model.GithubContext{EventName: "workflow_dispatch", Event: map[string]any{"inputs": map[string]any{"name": "dispatch"}}}
+
+	// the event's own inputs must not override those Gitea resolved
+	job := &RunContext{Config: config, Run: &model.Run{JobID: "job1", Workflow: wf}}
+	assert.Equal(t, map[string]any{"name": "caller", "target": "dispatch"}, getEvaluatorInputs(job, nil, ghc))
+
+	composite := &RunContext{Config: config, Run: &model.Run{JobID: "job1", Workflow: &model.Workflow{}}, Parent: job}
+	assert.Equal(t, map[string]any{"arg": "x"}, getEvaluatorInputs(composite, map[string]any{"arg": "x"}, ghc))
+}
+
 func TestResolveWorkflowCallToleratesMismatchesAndPassesInheritedSecretsVerbatim(t *testing.T) {
 	callerWorkflow, err := model.ReadWorkflow(strings.NewReader(`
 jobs: