feat: include source root in configure request (#2431)

Updates #1922

Author: JoeWang1127

internal/docker/docker.go

@@ -97,6 +97,9 @@ type ConfigureRequest struct {
 	// RepoDir is the local root directory of the language repository.
 	RepoDir string
 
+	// ExistingSourceRoots are existing source roots in the language repository.
+	ExistingSourceRoots []string
+
 	// GlobalFiles are global files of the language repository.
 	GlobalFiles []string
 
@@ -284,6 +287,10 @@ func (c *Docker) Configure(ctx context.Context, request *ConfigureRequest) (stri
 		fmt.Sprintf("%s:/input", generatorInput),
 		fmt.Sprintf("%s:/source:ro", request.ApiRoot), // readonly volume
 	}
+	// Mount existing source roots as a readonly volume.
+	for _, sourceRoot := range request.ExistingSourceRoots {
+		mounts = append(mounts, fmt.Sprintf("%s/%s:/repo/%s:ro", request.RepoDir, sourceRoot, sourceRoot))
+	}
 	// Mount global files as a readonly volume.
 	for _, globalFile := range request.GlobalFiles {
 		mounts = append(mounts, fmt.Sprintf("%s/%s:/repo/%s:ro", request.RepoDir, globalFile, globalFile))

internal/docker/docker_test.go

@@ -299,6 +299,73 @@ func TestDockerRun(t *testing.T) {
 				"--source=/source",
 			},
 		},
+		{
+			name: "configure_with_source_roots",
+			docker: &Docker{
+				Image: testImage,
+			},
+			runCommand: func(ctx context.Context, d *Docker) error {
+				configureRequest := &ConfigureRequest{
+					State:     state,
+					LibraryID: testLibraryID,
+					RepoDir:   repoDir,
+					ApiRoot:   testAPIRoot,
+					ExistingSourceRoots: []string{
+						"a/path",
+						"b/path",
+					},
+				}
+
+				_, err := d.Configure(ctx, configureRequest)
+
+				return err
+			},
+			want: []string{
+				"run", "--rm",
+				"-v", fmt.Sprintf("%s/.librarian:/librarian", repoDir),
+				"-v", fmt.Sprintf("%s/.librarian/generator-input:/input", repoDir),
+				"-v", fmt.Sprintf("%s:/source:ro", testAPIRoot),
+				"-v", fmt.Sprintf("%s/a/path:/repo/a/path:ro", repoDir),
+				"-v", fmt.Sprintf("%s/b/path:/repo/b/path:ro", repoDir),
+				testImage,
+				string(CommandConfigure),
+				"--librarian=/librarian",
+				"--input=/input",
+				"--repo=/repo",
+				"--source=/source",
+			},
+		},
+		{
+			name: "configure_with_nil_source_roots",
+			docker: &Docker{
+				Image: testImage,
+			},
+			runCommand: func(ctx context.Context, d *Docker) error {
+				configureRequest := &ConfigureRequest{
+					State:               state,
+					LibraryID:           testLibraryID,
+					RepoDir:             repoDir,
+					ApiRoot:             testAPIRoot,
+					ExistingSourceRoots: nil,
+				}
+
+				_, err := d.Configure(ctx, configureRequest)
+
+				return err
+			},
+			want: []string{
+				"run", "--rm",
+				"-v", fmt.Sprintf("%s/.librarian:/librarian", repoDir),
+				"-v", fmt.Sprintf("%s/.librarian/generator-input:/input", repoDir),
+				"-v", fmt.Sprintf("%s:/source:ro", testAPIRoot),
+				testImage,
+				string(CommandConfigure),
+				"--librarian=/librarian",
+				"--input=/input",
+				"--repo=/repo",
+				"--source=/source",
+			},
+		},
 		{
 			name: "configure_with_multiple_libraries_in_librarian_state",
 			docker: &Docker{

internal/librarian/generate.go

@@ -365,12 +365,13 @@ func (r *generateRunner) runConfigureCommand(ctx context.Context) (string, error
 	}
 
 	configureRequest := &docker.ConfigureRequest{
-		ApiRoot:     apiRoot,
-		HostMount:   r.hostMount,
-		LibraryID:   r.library,
-		RepoDir:     r.repo.GetDir(),
-		GlobalFiles: globalFiles,
-		State:       r.state,
+		ApiRoot:             apiRoot,
+		HostMount:           r.hostMount,
+		LibraryID:           r.library,
+		RepoDir:             r.repo.GetDir(),
+		GlobalFiles:         globalFiles,
+		ExistingSourceRoots: r.getExistingSrc(r.library),
+		State:               r.state,
 	}
 	slog.Info("Performing configuration for library", "id", r.library)
 	if _, err := r.containerClient.Configure(ctx, configureRequest); err != nil {
@@ -414,6 +415,20 @@ func (r *generateRunner) restoreLibrary(libraryID string) error {
 	return r.repo.CleanUntracked(library.SourceRoots)
 }
 
+// getExistingSrc returns source roots as-is of a given library ID, if the source roots exist in the language repo.
+func (r *generateRunner) getExistingSrc(libraryID string) []string {
+	library := findLibraryByID(r.state, libraryID)
+	var existingSrc []string
+	for _, src := range library.SourceRoots {
+		relPath := filepath.Join(r.repo.GetDir(), src)
+		if _, err := os.Stat(relPath); err == nil {
+			existingSrc = append(existingSrc, src)
+		}
+	}
+
+	return existingSrc
+}
+
 func setAllAPIStatus(state *config.LibrarianState, status string) {
 	for _, library := range state.Libraries {
 		for _, api := range library.APIs {

internal/librarian/generate_test.go

@@ -1124,3 +1124,69 @@ func TestUpdateLastGeneratedCommitState(t *testing.T) {
 		t.Errorf("updateState() got = %v, want %v", r.state.Libraries[0].LastGeneratedCommit, hash)
 	}
 }
+
+func TestGetExistingSrc(t *testing.T) {
+	t.Parallel()
+	for _, test := range []struct {
+		name  string
+		paths []string
+		want  []string
+	}{
+		{
+			name: "all_source_paths_existed",
+			paths: []string{
+				"a/path",
+				"another/path",
+			},
+			want: []string{
+				"a/path",
+				"another/path",
+			},
+		},
+		{
+			name: "one_source_paths_existed",
+			paths: []string{
+				"a/path",
+			},
+			want: []string{
+				"a/path",
+			},
+		},
+		{
+			name: "no_source_paths_existed",
+			want: nil,
+		},
+	} {
+		t.Run(test.name, func(t *testing.T) {
+			t.Parallel()
+			repo := newTestGitRepo(t)
+			state := &config.LibrarianState{
+				Libraries: []*config.LibraryState{
+					{
+						ID: "some-library",
+						SourceRoots: []string{
+							"a/path",
+							"another/path",
+						},
+					},
+				},
+			}
+			for _, path := range test.paths {
+				relPath := filepath.Join(repo.GetDir(), path)
+				if err := os.MkdirAll(relPath, 0755); err != nil {
+					t.Fatal(err)
+				}
+			}
+
+			r := &generateRunner{
+				repo:  repo,
+				state: state,
+			}
+
+			got := r.getExistingSrc("some-library")
+			if diff := cmp.Diff(test.want, got); diff != "" {
+				t.Errorf("getExistingSrc() mismatch (-want +got):%s", diff)
+			}
+		})
+	}
+}