fix: matrix-job data races + outputs, leaner offline test suite (#994)

Running the full suite under `-race` (dropping `-short`) exposed pre-existing data races in parallel matrix-job execution, fixed by not sharing mutable state across combinations:

- `containerDaemonSocket()`/`validVolumes()` derive per-job values instead of mutating shared `Config`
- `getWorkflowSecrets` builds a fresh map, `rc.steps()` clones each step, and go-git workdir access is serialized
- every write to a shared `Job`'s result/outputs runs under a per-`Job` lock, each combo interpolating outputs from a pristine snapshot (last wins, as on GitHub)

### Test suite

- capability gates (docker / network / host-tools / Linux) replace the `-short` skips, and the suite runs offline via local fixtures (the artifact flow uses an in-process loopback server, only the docker-action force-pull needs the network)
- drops redundant tests, adds a regression test for https://gitea.com/gitea/runner/issues/981 and a docker-in-docker harness (`make test-dind`)

---
This PR was written with the help of Claude Opus 4.7

Reviewed-on: https://gitea.com/gitea/runner/pulls/994
Reviewed-by: Nicolas <bircni@icloud.com>
Co-authored-by: silverwind <me@silverwind.io>
Co-committed-by: silverwind <me@silverwind.io>

act/runner/action_cache_test.go

@@ -8,64 +8,139 @@ import (
 	"archive/tar"
 	"bytes"
 	"context"
+	"fmt"
 	"io"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
 	"testing"
+	"time"
+
+	"gitea.com/gitea/runner/act/common"
+	"gitea.com/gitea/runner/act/model"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
-func TestActionCache(t *testing.T) {
-	if testing.Short() {
-		t.Skip("skipping integration test")
+func runGit(t *testing.T, dir string, args ...string) {
+	t.Helper()
+	if dir != "" {
+		args = append([]string{"-C", dir}, args...)
 	}
+	cmd := exec.Command("git", args...)
+	// Fixed identity and host-config isolation so commits succeed offline regardless of the
+	// host's git config (mirrors gitCmd in act/common/git).
+	cmd.Env = append(os.Environ(),
+		"GIT_AUTHOR_NAME=test", "GIT_AUTHOR_EMAIL=test@example.com",
+		"GIT_COMMITTER_NAME=test", "GIT_COMMITTER_EMAIL=test@example.com",
+		"GIT_CONFIG_GLOBAL=/dev/null", "GIT_CONFIG_SYSTEM=/dev/null",
+	)
+	out, err := cmd.CombinedOutput()
+	require.NoError(t, err, string(out))
+}
+
+// TestShortShaActionRejected verifies a `uses` ref that is a shortened commit SHA is rejected
+// with a clear error. The action is resolved from a local repo (via DefaultActionInstance) so
+// this runs offline.
+func TestShortShaActionRejected(t *testing.T) {
+	// a local "remote" action repo at <root>/actions/hello-world-docker-action
+	actionRoot := t.TempDir()
+	repo := filepath.Join(actionRoot, "actions", "hello-world-docker-action")
+	require.NoError(t, os.MkdirAll(repo, 0o755))
+	runGit(t, "", "init", "--initial-branch=main", repo)
+	require.NoError(t, os.WriteFile(filepath.Join(repo, "action.yml"),
+		[]byte("name: hello\nruns:\n  using: node24\n  main: index.js\n"), 0o644))
+	runGit(t, repo, "add", ".")
+	runGit(t, repo, "commit", "-m", "initial")
+	out, err := exec.Command("git", "-C", repo, "rev-parse", "HEAD").Output()
+	require.NoError(t, err)
+	shortSha := strings.TrimSpace(string(out))[:7]
+
+	// a workflow that uses the action at the short SHA
+	wfDir := filepath.Join(t.TempDir(), "wf")
+	require.NoError(t, os.MkdirAll(wfDir, 0o755))
+	wf := fmt.Sprintf("on: push\njobs:\n  test:\n    runs-on: ubuntu-latest\n    steps:\n      - uses: actions/hello-world-docker-action@%s\n", shortSha)
+	require.NoError(t, os.WriteFile(filepath.Join(wfDir, "push.yml"), []byte(wf), 0o644))
+
+	runner, err := New(&Config{
+		Workdir:               wfDir,
+		EventName:             "push",
+		Platforms:             map[string]string{"ubuntu-latest": baseImage},
+		GitHubInstance:        "github.com",
+		DefaultActionInstance: actionRoot,
+		ContainerMaxLifetime:  time.Hour,
+	})
+	require.NoError(t, err)
+	planner, err := model.NewWorkflowPlanner(wfDir, true)
+	require.NoError(t, err)
+	plan, err := planner.PlanEvent("push")
+	require.NoError(t, err)
+
+	err = runner.NewPlanExecutor(plan)(common.WithDryrun(context.Background(), true))
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "shortened version of a commit SHA")
+}
+
+func TestActionCache(t *testing.T) {
 	a := assert.New(t)
+	ctx := context.Background()
+
+	// Build a local bare repo with a `js` action dir so this runs offline (formerly cloned
+	// github.com/nektos/act-test-actions over the network). allowAnySHA1InWant lets the
+	// "Fetch Sha" case fetch a commit hash directly.
+	remoteDir := t.TempDir()
+	runGit(t, "", "init", "--bare", "--initial-branch=main", remoteDir)
+	runGit(t, remoteDir, "config", "uploadpack.allowAnySHA1InWant", "true")
+
+	workDir := t.TempDir()
+	runGit(t, "", "clone", remoteDir, workDir)
+	require.NoError(t, os.MkdirAll(filepath.Join(workDir, "js"), 0o755))
+	require.NoError(t, os.WriteFile(filepath.Join(workDir, "js", "action.yml"),
+		[]byte("name: js\nruns:\n  using: node24\n  main: index.js\n"), 0o644))
+	require.NoError(t, os.WriteFile(filepath.Join(workDir, "js", "index.js"),
+		[]byte("console.log('hello');\n"), 0o644))
+	runGit(t, workDir, "add", ".")
+	runGit(t, workDir, "commit", "-m", "initial")
+	runGit(t, workDir, "push", "-u", "origin", "main")
+
+	out, err := exec.Command("git", "-C", workDir, "rev-parse", "main").Output()
+	require.NoError(t, err)
+	fullSha := strings.TrimSpace(string(out))
+
 	cache := &GoGitActionCache{
 		Path: t.TempDir(),
 	}
-	ctx := context.Background()
-	cacheDir := "nektos/act-test-actions"
-	repo := "https://github.com/nektos/act-test-actions"
+	cacheDir := "local/act-test-actions"
 	refs := []struct {
-		Name     string
-		CacheDir string
-		Repo     string
-		Ref      string
+		Name string
+		Ref  string
 	}{
-		{
-			Name:     "Fetch Branch Name",
-			CacheDir: cacheDir,
-			Repo:     repo,
-			Ref:      "main",
-		},
-		{
-			Name:     "Fetch Branch Name Absolutely",
-			CacheDir: cacheDir,
-			Repo:     repo,
-			Ref:      "refs/heads/main",
-		},
-		{
-			Name:     "Fetch HEAD",
-			CacheDir: cacheDir,
-			Repo:     repo,
-			Ref:      "HEAD",
-		},
-		{
-			Name:     "Fetch Sha",
-			CacheDir: cacheDir,
-			Repo:     repo,
-			Ref:      "de984ca37e4df4cb9fd9256435a3b82c4a2662b1",
-		},
+		{Name: "Fetch Branch Name", Ref: "main"},
+		{Name: "Fetch Branch Name Absolutely", Ref: "refs/heads/main"},
+		{Name: "Fetch HEAD", Ref: "HEAD"},
+		{Name: "Fetch Sha", Ref: fullSha},
 	}
 	for _, c := range refs {
 		t.Run(c.Name, func(t *testing.T) {
-			sha, err := cache.Fetch(ctx, c.CacheDir, c.Repo, c.Ref, "")
+			sha, err := cache.Fetch(ctx, cacheDir, remoteDir, c.Ref, "")
 			if !a.NoError(err) || !a.NotEmpty(sha) { //nolint:testifylint // pre-existing issue from nektos/act
 				return
 			}
-			atar, err := cache.GetTarArchive(ctx, c.CacheDir, sha, "js")
-			if !a.NoError(err) || !a.NotEmpty(atar) { //nolint:testifylint // pre-existing issue from nektos/act
+			atar, err := cache.GetTarArchive(ctx, cacheDir, sha, "js")
+			// NotNil, not NotEmpty: atar is a live io.PipeReader whose producer goroutine is
+			// writing concurrently; NotEmpty deep-reflects over its internals and races.
+			if !a.NoError(err) || !a.NotNil(atar) { //nolint:testifylint // pre-existing issue from nektos/act
 				return
 			}
+			// GetTarArchive streams from a background goroutine walking the shared repo.
+			// Drain and close so it finishes before the next subtest fetches into the same
+			// repo; otherwise the lingering walk races with that fetch.
+			defer func() {
+				_, _ = io.Copy(io.Discard, atar)
+				_ = atar.Close()
+			}()
 			mytar := tar.NewReader(atar)
 			th, err := mytar.Next()
 			if !a.NoError(err) || !a.NotEqual(0, th.Size) { //nolint:testifylint // pre-existing issue from nektos/act