fix(repository): guarantee commit identity for fork worktrees (Windows CI)

Windows runners often lack a global git identity, so commits in the fork
worktree failed with “Author identity unknown”. The tests set user.name/email
only in the source repo, and worktree commits don’t inherit that.

Change:
- In ensureFork (under LockTypeForkRepo), ensure the fork repo has user.name
  and user.email. Copy from the source repo if set; otherwise use a local
  fallback (“container-use” / “container-use@local”).

Scope: container-use fork only (no global config). Covers createInitialCommit
and all subsequent worktree commits without sprinkling per-commit flags.

Signed-off-by: Guillaume de Rouville <guillaume@dagger.io>

Author: grouville

repository/git.go

@@ -481,6 +481,49 @@ func (r *Repository) addNonBinaryFiles(ctx context.Context, worktreePath string)
 	return nil
 }
 
+// fork worktrees may run on machines without a global identity (Windows CI).
+// Setting it up at the bare repo ensures consistent authorship for all worktrees
+func (r *Repository) ensureForkIdentity(ctx context.Context) error {
+	has := func(key string) bool {
+		v, err := RunGitCommand(ctx, r.forkRepoPath, "config", "--get", key)
+		return err == nil && strings.TrimSpace(v) != ""
+	}
+
+	needName := !has("user.name")
+	needEmail := !has("user.email")
+	if !needName && !needEmail {
+		return nil
+	}
+
+	// Prefer identity from the user's source repo, else fallback.
+	name := ""
+	email := ""
+	if v, err := RunGitCommand(ctx, r.userRepoPath, "config", "--get", "user.name"); err == nil {
+		name = strings.TrimSpace(v)
+	}
+	if v, err := RunGitCommand(ctx, r.userRepoPath, "config", "--get", "user.email"); err == nil {
+		email = strings.TrimSpace(v)
+	}
+	if name == "" {
+		name = "container-use"
+	}
+	if email == "" {
+		email = "container-use@local"
+	}
+
+	if needName {
+		if _, err := RunGitCommand(ctx, r.forkRepoPath, "config", "user.name", name); err != nil {
+			return err
+		}
+	}
+	if needEmail {
+		if _, err := RunGitCommand(ctx, r.forkRepoPath, "config", "user.email", email); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 func (r *Repository) shouldSkipFile(fileName string) bool {
 	skipExtensions := []string{
 		".tar", ".tar.gz", ".tgz", ".tar.bz2", ".tbz2", ".tar.xz", ".txz",

repository/git_test.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"os"
 	"path/filepath"
+	"runtime"
 	"strings"
 	"testing"
 
@@ -172,6 +173,58 @@ func TestCommitWorktreeChanges(t *testing.T) {
 	})
 }
 
+func TestEnsureForkSetsIdentityWhenMissing(t *testing.T) {
+	t.Setenv("HOME", t.TempDir())
+	if runtime.GOOS == "windows" {
+		t.Setenv("USERPROFILE", t.TempDir())
+	}
+
+	ctx := context.Background()
+	src := t.TempDir()
+	base := t.TempDir()
+
+	_, err := RunGitCommand(ctx, src, "init")
+	require.NoError(t, err)
+
+	r, err := OpenWithBasePath(ctx, src, base)
+	require.NoError(t, err)
+
+	name, err := RunGitCommand(ctx, r.forkRepoPath, "config", "--get", "user.name")
+	require.NoError(t, err)
+	email, err := RunGitCommand(ctx, r.forkRepoPath, "config", "--get", "user.email")
+	require.NoError(t, err)
+
+	assert.NotEmpty(t, strings.TrimSpace(name))
+	assert.NotEmpty(t, strings.TrimSpace(email))
+}
+
+func TestEnsureForkCopiesIdentityFromSourceRepo(t *testing.T) {
+	t.Setenv("HOME", t.TempDir())
+	if runtime.GOOS == "windows" {
+		t.Setenv("USERPROFILE", t.TempDir())
+	}
+
+	ctx := context.Background()
+	src := t.TempDir()
+	base := t.TempDir()
+
+	_, err := RunGitCommand(ctx, src, "init")
+	require.NoError(t, err)
+	_, err = RunGitCommand(ctx, src, "config", "user.name", "Source User")
+	require.NoError(t, err)
+	_, err = RunGitCommand(ctx, src, "config", "user.email", "source@example.com")
+	require.NoError(t, err)
+
+	r, err := OpenWithBasePath(ctx, src, base)
+	require.NoError(t, err)
+
+	name, _ := RunGitCommand(ctx, r.forkRepoPath, "config", "--get", "user.name")
+	email, _ := RunGitCommand(ctx, r.forkRepoPath, "config", "--get", "user.email")
+
+	assert.Equal(t, "Source User", strings.TrimSpace(name))
+	assert.Equal(t, "source@example.com", strings.TrimSpace(email))
+}
+
 // Test helper functions
 func writeFile(t *testing.T, dir, name, content string) {
 	t.Helper()

repository/repository.go

@@ -141,7 +141,8 @@ func (r *Repository) ensureFork(ctx context.Context) error {
 			os.RemoveAll(r.forkRepoPath)
 			return err
 		}
-		return nil
+
+		return r.ensureForkIdentity(ctx)
 	})
 }