feat: show run command, shell and env in collapsible group before step output (#847)

## Summary

Mirrors the GitHub Actions runner behaviour where each `run:` step shows a collapsible **"Run \<command\>"** section containing the script, shell command, and environment variables before the actual step output.

### What changes

- **`pkg/runner/step_run.go`**: In `stepRun.main()`, two new executors are added to the pipeline:
  1. `logRunGroupHeader()` — runs after `setupShellCommandExecutor()` (so `sr.cmdline` is already resolved). Emits a `::group::Run <step>` log entry followed by the interpolated script, the full shell command line, and the step's env vars (sorted, internal vars filtered out).
  2. The existing execution function now has `defer rawLogger.Infof("::endgroup::")` so the group is closed after the step finishes, regardless of success or failure.

### Env var filtering

Internal runner vars are hidden (`GITHUB_*`, `GITEA_*`, `RUNNER_*`, `INPUT_*`, `PATH`, `HOME`) — only user-relevant vars are shown, matching what GitHub Actions displays.

### Example output

```
▼ Run cargo build
  cargo build
  shell: bash --noprofile --norc -e -o pipefail {0}
  env:
    CARGO_HOME: /home/runner/.cargo
    CARGO_INCREMENTAL: 0
    CARGO_TERM_COLOR: always
  <actual build output>
```

---------

Co-authored-by: silverwind <2021+silverwind@noreply.gitea.com>
Co-authored-by: silverwind <me@silverwind.io>
Reviewed-on: https://gitea.com/gitea/act_runner/pulls/847
Reviewed-by: silverwind <2021+silverwind@noreply.gitea.com>
Reviewed-by: ChristopherHX <38043+christopherhx@noreply.gitea.com>

act/runner/step_run.go

@@ -9,6 +9,7 @@ import (
 	"fmt"
 	"maps"
 	"runtime"
+	"slices"
 	"strings"
 
 	"gitea.com/gitea/act_runner/act/common"
@@ -17,15 +18,18 @@ import (
 	"gitea.com/gitea/act_runner/act/model"
 
 	"github.com/kballard/go-shellquote"
+	yaml "go.yaml.in/yaml/v4"
 )
 
 type stepRun struct {
-	Step             *model.Step
-	RunContext       *RunContext
-	cmd              []string
-	cmdline          string
-	env              map[string]string
-	WorkingDirectory string
+	Step               *model.Step
+	RunContext         *RunContext
+	cmd                []string
+	cmdline            string
+	env                map[string]string
+	WorkingDirectory   string
+	interpolatedScript string
+	shellCommand       string
 }
 
 func (sr *stepRun) pre() common.Executor {
@@ -39,15 +43,154 @@ func (sr *stepRun) main() common.Executor {
 	return runStepExecutor(sr, stepStageMain, common.NewPipelineExecutor(
 		sr.setupShellCommandExecutor(),
 		func(ctx context.Context) error {
-			sr.getRunContext().ApplyExtraPath(ctx, &sr.env)
-			if he, ok := sr.getRunContext().JobContainer.(*container.HostEnvironment); ok && he != nil {
+			rc := sr.getRunContext()
+			// Apply ::add-path:: effects before printing so PATH is accurate in the env: block.
+			rc.ApplyExtraPath(ctx, &sr.env)
+			sr.printRunScriptActionDetails(ctx)
+			if he, ok := rc.JobContainer.(*container.HostEnvironment); ok && he != nil {
 				return he.ExecWithCmdLine(sr.cmd, sr.cmdline, sr.env, "", sr.WorkingDirectory)(ctx)
 			}
-			return sr.getRunContext().JobContainer.Exec(sr.cmd, sr.env, "", sr.WorkingDirectory)(ctx)
+			return rc.JobContainer.Exec(sr.cmd, sr.env, "", sr.WorkingDirectory)(ctx)
 		},
 	))
 }
 
+// printRunScriptActionDetails mirrors actions/runner ScriptHandler.PrintActionDetails
+// for script steps.
+func (sr *stepRun) printRunScriptActionDetails(ctx context.Context) {
+	rawLogger := common.Logger(ctx).WithField(rawOutputField, true)
+	scriptLineLogger := rawLogger.WithField(scriptLineCyanField, true)
+
+	normalized := strings.TrimRight(strings.ReplaceAll(sr.interpolatedScript, "\r\n", "\n"), "\n")
+
+	rawLogger.Infof("::group::Run %s", sr.runScriptGroupTitle(normalized))
+
+	if normalized != "" {
+		for line := range strings.SplitSeq(normalized, "\n") {
+			scriptLineLogger.Info(line)
+		}
+	}
+
+	rawLogger.Infof("shell: %s", sr.shellCommand)
+
+	printStepEnvBlock(ctx, sr.Step, sr.env, sr.getRunContext())
+	rawLogger.Infof("::endgroup::")
+}
+
+// printRunActionHeader mirrors actions/runner's "Run <action>" header for `uses:` steps,
+// including the with: inputs and the step-level env: block. The caller is responsible
+// for emitting ::endgroup:: after the action finishes.
+func printRunActionHeader(ctx context.Context, step *model.Step, env map[string]string, rc *RunContext) {
+	if step == nil {
+		return
+	}
+	rawLogger := common.Logger(ctx).WithField(rawOutputField, true)
+
+	title := step.Uses
+	if step.Name != "" {
+		title = step.Name
+	}
+	rawLogger.Infof("::group::Run %s", title)
+
+	if len(step.With) > 0 {
+		rawLogger.Infof("with:")
+		for _, k := range slices.Sorted(maps.Keys(step.With)) {
+			rawLogger.Infof("  %s: %s", k, step.With[k])
+		}
+	}
+
+	printStepEnvBlock(ctx, step, env, rc)
+}
+
+// printStepEnvBlock emits the declared-env block (YAML order, internal vars filtered)
+// shared by the run: and uses: "Run" headers.
+func printStepEnvBlock(ctx context.Context, step *model.Step, env map[string]string, rc *RunContext) {
+	rawLogger := common.Logger(ctx).WithField(rawOutputField, true)
+	caseInsensitive := rc != nil && rc.JobContainer != nil && rc.JobContainer.IsEnvironmentCaseInsensitive()
+	var visible []string
+	for _, k := range stepDeclaredEnvKeysInOrder(step) {
+		if !isInternalEnvKey(k, caseInsensitive) {
+			visible = append(visible, k)
+		}
+	}
+	if len(visible) == 0 {
+		return
+	}
+	rawLogger.Infof("env:")
+	envLookup := env
+	if caseInsensitive {
+		envLookup = make(map[string]string, len(env))
+		for k, v := range env {
+			envLookup[strings.ToUpper(k)] = v
+		}
+	}
+	for _, k := range visible {
+		lookupKey := k
+		if caseInsensitive {
+			lookupKey = strings.ToUpper(k)
+		}
+		rawLogger.Infof("  %s: %s", k, envLookup[lookupKey])
+	}
+}
+
+// isInternalEnvKey matches actions/runner's filtered set of vars that are hidden
+// from the "Run" header's env: block because they are injected by the runner itself.
+func isInternalEnvKey(k string, caseInsensitive bool) bool {
+	upper := k
+	if caseInsensitive {
+		upper = strings.ToUpper(k)
+	}
+	switch upper {
+	case "PATH", "HOME", "CI":
+		return true
+	}
+	return strings.HasPrefix(upper, "GITHUB_") ||
+		strings.HasPrefix(upper, "GITEA_") ||
+		strings.HasPrefix(upper, "RUNNER_") ||
+		strings.HasPrefix(upper, "INPUT_")
+}
+
+func (sr *stepRun) runScriptGroupTitle(normalizedScript string) string {
+	trimmed := strings.TrimLeft(normalizedScript, " \t\r\n")
+	if idx := strings.IndexAny(trimmed, "\r\n"); idx >= 0 {
+		trimmed = trimmed[:idx]
+	}
+	if trimmed != "" {
+		return trimmed
+	}
+	if sr.Step != nil {
+		if sr.Step.Name != "" {
+			return sr.Step.Name
+		}
+		return sr.Step.ID
+	}
+	return ""
+}
+
+// stepDeclaredEnvKeysInOrder walks the raw YAML Env mapping so keys are emitted in
+// the order the workflow author wrote them; step.Environment() decodes into a Go map
+// and loses ordering.
+func stepDeclaredEnvKeysInOrder(step *model.Step) []string {
+	if step == nil || step.Env.Kind != yaml.MappingNode {
+		return nil
+	}
+	content := step.Env.Content
+	keys := make([]string, 0, len(content)/2)
+	seen := make(map[string]struct{}, len(content)/2)
+	for i := 0; i+1 < len(content); i += 2 {
+		k := content[i]
+		if k.Kind != yaml.ScalarNode || k.Tag == "!!merge" || k.Value == "<<" {
+			continue
+		}
+		if _, dup := seen[k.Value]; dup {
+			continue
+		}
+		seen[k.Value] = struct{}{}
+		keys = append(keys, k.Value)
+	}
+	return keys
+}
+
 func (sr *stepRun) post() common.Executor {
 	return func(ctx context.Context) error {
 		return nil
@@ -111,8 +254,10 @@ func (sr *stepRun) setupShellCommand(ctx context.Context) (name, script string,
 	step := sr.Step
 
 	script = sr.RunContext.NewStepExpressionEvaluator(ctx, sr).Interpolate(ctx, step.Run)
+	sr.interpolatedScript = script
 
 	scCmd := step.ShellCommand()
+	sr.shellCommand = scCmd
 
 	name = getScriptName(sr.RunContext, step)