Merge branch 'fix/detect-default-branch'

Author: hext-dev

git/git.go

@@ -94,7 +94,10 @@ func CloneRepo(ctx context.Context, logf func(string, ...any), opts CloneRepoOpt
 	}
 	reference := parsed.Fragment
 	if reference == "" && opts.SingleBranch {
-		reference = "refs/heads/main"
+		// When SingleBranch is true and no branch is specified, don't set a
+		// default. go-git will automatically detect and use the remote's HEAD
+		// (default branch) via the "+HEAD:refs/remotes/origin/HEAD" refspec.
+		logf("No branch specified, using remote's default branch")
 	}
 	parsed.RawFragment = ""
 	parsed.Fragment = ""

git/git_test.go

@@ -168,6 +168,39 @@ func TestCloneRepo(t *testing.T) {
 	}
 }
 
+func TestCloneRepo_NonMainDefaultBranch(t *testing.T) {
+	t.Parallel()
+
+	// Test that cloning works when the remote's default branch is not "main".
+	// This verifies that we detect the remote's HEAD instead of hardcoding "main".
+	for _, defaultBranch := range []string{"master", "develop", "trunk"} {
+		defaultBranch := defaultBranch
+		t.Run(defaultBranch, func(t *testing.T) {
+			t.Parallel()
+			srvFS := memfs.New()
+			_ = gittest.NewRepoWithBranch(t, srvFS, defaultBranch,
+				gittest.Commit(t, "README.md", "Hello from "+defaultBranch, "Initial commit"),
+			)
+			srv := httptest.NewServer(gittest.NewServer(srvFS))
+			t.Cleanup(srv.Close)
+
+			clientFS := memfs.New()
+			cloned, err := git.CloneRepo(context.Background(), t.Logf, git.CloneRepoOptions{
+				Path:         "/workspace",
+				RepoURL:      srv.URL,
+				Storage:      clientFS,
+				SingleBranch: true, // This triggers the default branch detection
+			})
+			require.NoError(t, err)
+			require.True(t, cloned)
+
+			// Verify the file was cloned correctly
+			readme := mustRead(t, clientFS, "/workspace/README.md")
+			require.Equal(t, "Hello from "+defaultBranch, readme)
+		})
+	}
+}
+
 func TestShallowCloneRepo(t *testing.T) {
 	t.Parallel()
 

testutil/gittest/gittest.go

@@ -251,15 +251,20 @@ func Commit(t *testing.T, path, content, msg string) CommitFunc {
 	}
 }
 
-// NewRepo returns a new Git repository.
+// NewRepo returns a new Git repository with "main" as the default branch.
 func NewRepo(t *testing.T, fs billy.Filesystem, commits ...CommitFunc) *git.Repository {
+	return NewRepoWithBranch(t, fs, "main", commits...)
+}
+
+// NewRepoWithBranch returns a new Git repository with a custom default branch.
+func NewRepoWithBranch(t *testing.T, fs billy.Filesystem, defaultBranch string, commits ...CommitFunc) *git.Repository {
 	t.Helper()
 	storage := filesystem.NewStorage(fs, cache.NewObjectLRU(cache.DefaultMaxSize))
 	repo, err := git.Init(storage, fs)
 	require.NoError(t, err)
 
-	// This changes the default ref to main instead of master.
-	h := plumbing.NewSymbolicReference(plumbing.HEAD, plumbing.ReferenceName("refs/heads/main"))
+	// Set the default branch to the specified name.
+	h := plumbing.NewSymbolicReference(plumbing.HEAD, plumbing.ReferenceName("refs/heads/"+defaultBranch))
 	err = storage.SetReference(h)
 	require.NoError(t, err)