chore(internal/legacylibrarian): sync library versions in configuration

internal/legacylibrarian/legacylibrarian/release_stage.go

@@ -16,19 +16,25 @@ package legacylibrarian
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"log/slog"
 	"os"
 	"path/filepath"
 	"slices"
 	"strings"
 
+	"github.com/googleapis/librarian/internal/config"
 	"github.com/googleapis/librarian/internal/legacylibrarian/legacyconfig"
 	"github.com/googleapis/librarian/internal/legacylibrarian/legacydocker"
 	"github.com/googleapis/librarian/internal/legacylibrarian/legacygitrepo"
+	"github.com/googleapis/librarian/internal/librarian"
 	"github.com/googleapis/librarian/internal/semver"
+	"github.com/googleapis/librarian/internal/yaml"
 )
 
+var errVersionRegression = errors.New("version is regression")
+
 type stageRunner struct {
 	branch          string
 	commit          bool
@@ -87,6 +93,9 @@ func (r *stageRunner) run(ctx context.Context) error {
 	if err := saveLibrarianState(r.repo.GetDir(), r.state); err != nil {
 		return err
 	}
+	if err := r.updateLibrarianYAML(ctx); err != nil {
+		return err
+	}
 
 	prBodyBuilder := func() (string, error) {
 		gitHubRepo, err := GetGitHubRepositoryFromGitRepo(r.repo)
@@ -366,3 +375,36 @@ func toCommit(c []*legacygitrepo.ConventionalCommit, libraryID string) []*legacy
 	}
 	return commits
 }
+
+func (r *stageRunner) updateLibrarianYAML(ctx context.Context) error {
+	librarianYAMLPath := filepath.Join(r.repo.GetDir(), config.LibrarianYAML)
+	cfg, err := yaml.Read[config.Config](librarianYAMLPath)
+	if err != nil {
+		if errors.Is(err, os.ErrNotExist) {
+			return nil
+		}
+		return err
+	}
+	newCfg, err := syncVersion(r.state, cfg)
+	if err != nil {
+		return err
+	}
+	return librarian.RunTidyOnConfig(ctx, r.repo.GetDir(), newCfg)
+}
+
+func syncVersion(state *legacyconfig.LibrarianState, cfg *config.Config) (*config.Config, error) {
+	for _, lib := range cfg.Libraries {
+		legacyLibrary := state.LibraryByID(lib.Name)
+		if legacyLibrary == nil || legacyLibrary.Version == "" {
+			continue
+		}
+		maxVersion := semver.MaxVersion(lib.Version, legacyLibrary.Version)
+		if maxVersion == lib.Version && legacyLibrary.Version != lib.Version {
+			// lib.Version is greater than legacyLibrary.Version, something is
+			// wrong, fail in this case.
+			return nil, fmt.Errorf("library %s, version in state, %s, is smaller than version in librarian.yaml, %s: %w", lib.Name, legacyLibrary.Version, lib.Version, errVersionRegression)
+		}
+		lib.Version = legacyLibrary.Version
+	}
+	return cfg, nil
+}