Discover checkout roots for optional preparation

internal/git/discovery_test.go

@@ -0,0 +1,111 @@
+package git
+
+import (
+	"context"
+	"errors"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func TestDiscoverRepositoryRoot(t *testing.T) {
+	repo := newRemoteFixture(t)
+	child := filepath.Join(repo.work, "child")
+	if err := os.Mkdir(child, 0755); err != nil {
+		t.Fatal(err)
+	}
+	alias := filepath.Join(t.TempDir(), "alias")
+	if err := os.Symlink(repo.work, alias); err != nil {
+		t.Fatal(err)
+	}
+	worktree := filepath.Join(t.TempDir(), "worktree")
+	gitRun(t, repo.work, "worktree", "add", "--detach", worktree)
+	for _, tc := range []struct{ dir, want string }{{repo.work, repo.work}, {child, repo.work}, {alias, repo.work}, {worktree, worktree}} {
+		root, found, err := DiscoverRepositoryRoot(context.Background(), tc.dir)
+		want, e := filepath.EvalSymlinks(tc.want)
+		if e != nil {
+			t.Fatal(e)
+		}
+		if err != nil || !found || root != want {
+			t.Fatalf("Discover(%s) = %q, %t, %v; want %q", tc.dir, root, found, err, want)
+		}
+	}
+	standalone := t.TempDir()
+	if root, found, err := DiscoverRepositoryRoot(context.Background(), standalone); err != nil || found || root != "" {
+		t.Fatalf("standalone = %q, %t, %v", root, found, err)
+	}
+	if _, err := RepositoryRoot(context.Background(), standalone); err == nil {
+		t.Fatal("strict lookup accepted standalone")
+	}
+	broken := t.TempDir()
+	if err := os.WriteFile(filepath.Join(broken, ".git"), []byte("gitdir: missing\n"), 0600); err != nil {
+		t.Fatal(err)
+	}
+	if _, found, err := DiscoverRepositoryRoot(context.Background(), broken); err == nil || found {
+		t.Fatalf("broken marker: found %t, error %v", found, err)
+	}
+	if _, found, err := DiscoverRepositoryRoot(context.Background(), filepath.Join(standalone, "missing")); err == nil || found {
+		t.Fatalf("missing directory: found %t, error %v", found, err)
+	}
+}
+
+func TestNoRepositoryDiagnostic(t *testing.T) {
+	for _, tc := range []struct {
+		message string
+		want    bool
+	}{
+		{"fatal: not a git repository (or any of the parent directories): .git\n", true},
+		{"fatal: not a git repository (or any parent up to mount point /some path)\nStopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).\n", true},
+		{"fatal: not a git repository: '/bad'", false},
+		{"fatal: detected dubious ownership in repository", false},
+	} {
+		if got := noRepositoryDiagnostic(tc.message); got != tc.want {
+			t.Errorf("diagnostic %q = %t", tc.message, got)
+		}
+	}
+}
+
+func TestDiscoverRepositoryRootFailures(t *testing.T) {
+	dir := t.TempDir()
+	bin := t.TempDir()
+	script := "#!/bin/sh\nprintf '%s\\n' 'fatal: detected dubious ownership in repository' >&2\nexit 128\n"
+	if err := os.WriteFile(filepath.Join(bin, "git"), []byte(script), 0755); err != nil {
+		t.Fatal(err)
+	}
+	t.Setenv("PATH", bin)
+	_, found, err := DiscoverRepositoryRoot(context.Background(), dir)
+	var exitErr *exec.ExitError
+	if found || !errors.As(err, &exitErr) || exitErr.ExitCode() != 128 || !strings.Contains(err.Error(), "dubious ownership") {
+		t.Fatalf("found %t, error %v", found, err)
+	}
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel()
+	if _, _, err := DiscoverRepositoryRoot(ctx, dir); !errors.Is(err, context.Canceled) {
+		t.Fatalf("cancellation = %v", err)
+	}
+}
+
+func TestDiscoverRepositoryRootWithoutGit(t *testing.T) {
+	repo := newRemoteFixture(t)
+	standalone := t.TempDir()
+	t.Setenv("PATH", t.TempDir())
+	if _, found, err := DiscoverRepositoryRoot(context.Background(), standalone); found || err != nil {
+		t.Fatalf("standalone: found %t, error %v", found, err)
+	}
+	if _, found, err := DiscoverRepositoryRoot(context.Background(), repo.work); found || !errors.Is(err, exec.ErrNotFound) {
+		t.Fatalf("checkout: found %t, error %v", found, err)
+	}
+	broken := t.TempDir()
+	if err := os.WriteFile(filepath.Join(broken, ".git"), []byte("broken"), 0600); err != nil {
+		t.Fatal(err)
+	}
+	if _, found, err := DiscoverRepositoryRoot(context.Background(), broken); found || !errors.Is(err, exec.ErrNotFound) {
+		t.Fatalf("broken marker: found %t, error %v", found, err)
+	}
+	t.Setenv("GIT_DIR", "invalid")
+	if _, found, err := DiscoverRepositoryRoot(context.Background(), standalone); found || !errors.Is(err, exec.ErrNotFound) {
+		t.Fatalf("explicit context: found %t, error %v", found, err)
+	}
+}