fix: [CODE-2717]: Modify Sync to take DefaultBranch as input (#2962)

app/services/importer/repository.go

@@ -314,16 +314,12 @@ func (r *Repository) Handle(ctx context.Context, data string, _ job.ProgressRepo
 
 		log.Info().Msg("sync repository")
 
-		defaultBranch, err := r.syncGitRepository(ctx, &systemPrincipal, repo, cloneURLWithAuth)
+		err = r.syncGitRepository(ctx, &systemPrincipal, repo, cloneURLWithAuth)
 		if err != nil {
 			return fmt.Errorf("failed to sync git repository from '%s': %w", input.CloneURL, err)
 		}
 
-		log.Info().Msgf("successfully synced repository (returned default branch: '%s')", defaultBranch)
-
-		if defaultBranch == "" {
-			defaultBranch = r.defaultBranch
-		}
+		log.Info().Msgf("successfully synced repository (with default branch: %q)", repo.DefaultBranch)
 
 		log.Info().Msg("update repo in DB")
 
@@ -333,7 +329,6 @@ func (r *Repository) Handle(ctx context.Context, data string, _ job.ProgressRepo
 			}
 
 			repo.GitUID = gitUID
-			repo.DefaultBranch = defaultBranch
 			repo.State = enum.RepoStateActive
 
 			return nil
@@ -463,23 +458,24 @@ func (r *Repository) syncGitRepository(ctx context.Context,
 	principal *types.Principal,
 	repo *types.Repository,
 	sourceCloneURL string,
-) (string, error) {
+) error {
 	writeParams, err := r.createRPCWriteParams(ctx, principal, repo)
 	if err != nil {
-		return "", err
+		return err
 	}
 
-	syncOut, err := r.git.SyncRepository(ctx, &git.SyncRepositoryParams{
+	_, err = r.git.SyncRepository(ctx, &git.SyncRepositoryParams{
 		WriteParams:       writeParams,
 		Source:            sourceCloneURL,
 		CreateIfNotExists: false,
 		RefSpecs:          []string{"refs/heads/*:refs/heads/*", "refs/tags/*:refs/tags/*"},
+		DefaultBranch:     repo.DefaultBranch,
 	})
 	if err != nil {
-		return "", fmt.Errorf("failed to sync repository: %w", err)
+		return fmt.Errorf("failed to sync repository: %w", err)
 	}
 
-	return syncOut.DefaultBranch, nil
+	return nil
 }
 
 func (r *Repository) deleteGitRepository(ctx context.Context,

git/api/branch.go

@@ -96,14 +96,22 @@ func (g *Git) HasBranches(
 
 func (g *Git) IsBranchExist(ctx context.Context, repoPath, name string) (bool, error) {
 	cmd := command.New("show-ref",
-		command.WithFlag("--verify", BranchPrefix+name),
+		command.WithFlag("--exists", BranchPrefix+name),
 	)
 	err := cmd.Run(ctx,
 		command.WithDir(repoPath),
 	)
-	if err != nil {
-		return false, fmt.Errorf("failed to check if branch '%s' exist: %w", name, err)
+	if cmdERR := command.AsError(err); cmdERR != nil && cmdERR.IsExitCode(2) {
+		// git returns exit code 2 in case the ref doesn't exist.
+		// On success it would be 0 and no error would be returned in the first place.
+		// Any other exit code we fall through to default error handling.
+		// https://git-scm.com/docs/git-show-ref#Documentation/git-show-ref.txt---exists
+		return false, nil
 	}
+	if err != nil {
+		return false, processGitErrorf(err, "failed to check if branch %q exist", name)
+	}
+
 	return true, nil
 }
 

git/api/repo.go

@@ -24,6 +24,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/harness/gitness/errors"
 	"github.com/harness/gitness/git/command"
 
 	"github.com/rs/zerolog/log"
@@ -98,27 +99,28 @@ func (g *Git) SetDefaultBranch(
 	ctx context.Context,
 	repoPath string,
 	defaultBranch string,
-	allowEmpty bool,
+	ignoreBranchExistance bool,
 ) error {
 	if repoPath == "" {
 		return ErrRepositoryPathEmpty
 	}
 
-	// if requested, error out if branch doesn't exist. Otherwise, blindly set it.
-	exist, err := g.IsBranchExist(ctx, repoPath, defaultBranch)
-	if err != nil {
-		log.Ctx(ctx).Err(err).Msgf("failed to set default branch")
-	}
-	if !allowEmpty && !exist {
-		// TODO: ensure this returns not found error to caller
-		return fmt.Errorf("branch '%s' does not exist", defaultBranch)
+	if !ignoreBranchExistance {
+		// best effort try to check for existence - technically someone else could delete it in the meanwhile.
+		exist, err := g.IsBranchExist(ctx, repoPath, defaultBranch)
+		if err != nil {
+			return fmt.Errorf("failed to check if branch exists: %w", err)
+		}
+		if !exist {
+			return errors.NotFound("branch %q does not exist", defaultBranch)
+		}
 	}
 
 	// change default branch
 	cmd := command.New("symbolic-ref",
 		command.WithArg("HEAD", gitReferenceNamePrefixBranch+defaultBranch),
 	)
-	err = cmd.Run(ctx, command.WithDir(repoPath))
+	err := cmd.Run(ctx, command.WithDir(repoPath))
 	if err != nil {
 		return processGitErrorf(err, "failed to set new default branch")
 	}
@@ -130,6 +132,26 @@ func (g *Git) SetDefaultBranch(
 func (g *Git) GetDefaultBranch(
 	ctx context.Context,
 	repoPath string,
+) (string, error) {
+	rawBranchRef, err := g.GetSymbolicRefHeadRaw(ctx, repoPath)
+	if err != nil {
+		return "", fmt.Errorf("failed to get raw symbolic ref HEAD: %w", err)
+	}
+
+	branchName := strings.TrimPrefix(
+		strings.TrimSpace(
+			rawBranchRef,
+		),
+		BranchPrefix,
+	)
+
+	return branchName, nil
+}
+
+// GetSymbolicRefHeadRaw returns the raw output of the symolic-ref command for HEAD.
+func (g *Git) GetSymbolicRefHeadRaw(
+	ctx context.Context,
+	repoPath string,
 ) (string, error) {
 	if repoPath == "" {
 		return "", ErrRepositoryPathEmpty
@@ -144,7 +166,7 @@ func (g *Git) GetDefaultBranch(
 		command.WithDir(repoPath),
 		command.WithStdout(output))
 	if err != nil {
-		return "", processGitErrorf(err, "failed to get default branch")
+		return "", processGitErrorf(err, "failed to get value of symbolic ref HEAD from git")
 	}
 
 	return output.String(), nil

git/repo.go

@@ -109,6 +109,10 @@ type SyncRepositoryParams struct {
 	// RefSpecs [OPTIONAL] allows to override the refspecs that are being synced from the remote repository.
 	// By default all references present on the remote repository will be fetched (including scm internal ones).
 	RefSpecs []string
+	// DefaultBranch [OPTIONAL] allows to override the default branch of the repository.
+	// If empty, the default branch will be set to match the remote repository's default branch.
+	// WARNING: If the remote repo is empty and no value is provided, an api.ErrNoDefaultBranch error is returned.
+	DefaultBranch string
 }
 
 type SyncRepositoryOutput struct {
@@ -130,7 +134,15 @@ type HashRepositoryOutput struct {
 }
 type UpdateDefaultBranchParams struct {
 	WriteParams
-	// BranchName is the name of the branch
+	// BranchName is the name of the branch (not the full reference).
+	BranchName string
+}
+
+type GetDefaultBranchParams struct {
+	ReadParams
+}
+type GetDefaultBranchOutput struct {
+	// BranchName is the name of the branch (not the full reference).
 	BranchName string
 }
 
@@ -259,7 +271,7 @@ func (s *Service) SyncRepository(
 		}
 
 		// the default branch doesn't matter for a sync,
-		// we create an empty repo and the head will by updated as part of the Sync.
+		// we create an empty repo and the head will by updated later.
 		const syncDefaultBranch = "main"
 		if err = s.createRepositoryInternal(
 			ctx,
@@ -278,24 +290,22 @@ func (s *Service) SyncRepository(
 	// sync repo content
 	err = s.git.Sync(ctx, repoPath, params.Source, params.RefSpecs)
 	if err != nil {
-		return nil, fmt.Errorf("SyncRepository: failed to sync git repo: %w", err)
+		return nil, fmt.Errorf("failed to sync from source repo: %w", err)
 	}
 
-	// get remote default branch
-	defaultBranch, err := s.git.GetRemoteDefaultBranch(ctx, params.Source)
-	if errors.Is(err, api.ErrNoDefaultBranch) {
-		return &SyncRepositoryOutput{
-			DefaultBranch: "",
-		}, nil
-	}
-	if err != nil {
-		return nil, fmt.Errorf("SyncRepository: failed to get default branch from repo: %w", err)
+	defaultBranch := params.DefaultBranch
+	if defaultBranch == "" {
+		// get default branch from remote repo (returns api.ErrNoDefaultBranch if repo is empty!)
+		defaultBranch, err = s.git.GetRemoteDefaultBranch(ctx, params.Source)
+		if err != nil {
+			return nil, fmt.Errorf("failed to get default branch from source repo: %w", err)
+		}
 	}
 
 	// set default branch
 	err = s.git.SetDefaultBranch(ctx, repoPath, defaultBranch, true)
 	if err != nil {
-		return nil, fmt.Errorf("SyncRepository: failed to set default branch of repo: %w", err)
+		return nil, fmt.Errorf("failed to set default branch of repo: %w", err)
 	}
 
 	return &SyncRepositoryOutput{
@@ -329,7 +339,8 @@ func (s *Service) HashRepository(ctx context.Context, params *HashRepositoryPara
 		}()
 
 		// add default branch to hash
-		defaultBranch, err := s.git.GetDefaultBranch(goCtx, repoPath)
+		// IMPORTANT: Has to stay as is to ensure hash consistency! (e.g. "refs/heads/main/n")
+		defaultBranchRef, err := s.git.GetSymbolicRefHeadRaw(goCtx, repoPath)
 		if err != nil {
 			hashChan <- hash.SourceNext{
 				Err: fmt.Errorf("HashRepository: failed to get default branch: %w", err),
@@ -338,7 +349,7 @@ func (s *Service) HashRepository(ctx context.Context, params *HashRepositoryPara
 		}
 
 		hashChan <- hash.SourceNext{
-			Data: hash.SerializeHead(defaultBranch),
+			Data: hash.SerializeHead(defaultBranchRef),
 		}
 
 		err = s.git.WalkReferences(goCtx, repoPath, func(wre api.WalkReferencesEntry) error {
@@ -515,6 +526,26 @@ func (s *Service) GetRepositorySize(
 	}, nil
 }
 
+// GetDefaultBranch returns the default branch of the repo.
+func (s *Service) GetDefaultBranch(
+	ctx context.Context,
+	params *GetDefaultBranchParams,
+) (*GetDefaultBranchOutput, error) {
+	if err := params.Validate(); err != nil {
+		return nil, err
+	}
+
+	repoPath := getFullPathForRepo(s.reposRoot, params.RepoUID)
+
+	dfltBranch, err := s.git.GetDefaultBranch(ctx, repoPath)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get repo default branch: %w", err)
+	}
+	return &GetDefaultBranchOutput{
+		BranchName: dfltBranch,
+	}, nil
+}
+
 // UpdateDefaultBranch updates the default branch of the repo.
 func (s *Service) UpdateDefaultBranch(
 	ctx context.Context,
@@ -531,7 +562,7 @@ func (s *Service) UpdateDefaultBranch(
 
 	err := s.git.SetDefaultBranch(ctx, repoPath, params.BranchName, false)
 	if err != nil {
-		return fmt.Errorf("UpdateDefaultBranch: failed to update repo default branch %q: %w",
+		return fmt.Errorf("failed to update repo default branch %q: %w",
 			params.BranchName, err)
 	}
 	return nil

git/summary.go

@@ -17,8 +17,8 @@ package git
 import (
 	"context"
 	"fmt"
-	"strings"
 
+	"github.com/harness/gitness/git/api"
 	"github.com/harness/gitness/git/merge"
 
 	"golang.org/x/sync/errgroup"
@@ -44,7 +44,7 @@ func (s *Service) Summary(
 	if err != nil {
 		return SummaryOutput{}, err
 	}
-	defaultBranch = strings.TrimSpace(defaultBranch)
+	defaultBranchRef := api.GetReferenceFromBranchName(defaultBranch)
 
 	g, ctx := errgroup.WithContext(ctx)
 
@@ -52,7 +52,7 @@ func (s *Service) Summary(
 
 	g.Go(func() error {
 		var err error
-		commitCount, err = merge.CommitCount(ctx, repoPath, "", defaultBranch)
+		commitCount, err = merge.CommitCount(ctx, repoPath, "", defaultBranchRef)
 		return err
 	})