localrepo: Add WithoutAlternates option to repository size

There are times when we need to exclude the alternates directory from
the repository size calculation. Provide an option to do so.

2 files changed, 49 insertions, 0 deletions

diff --git a/internal/git/localrepo/repo.go b/internal/git/localrepo/repo.go
index 97525a1fc..3fef482e8 100644
--- a/internal/git/localrepo/repo.go
+++ b/internal/git/localrepo/repo.go
@@ -100,6 +100,9 @@ type repoSizeConfig struct {
 	// Excludes is a list of ref glob patterns to exclude from the size
 	// calculation.
 	Excludes []string
+	// ExcludeAlternates will exclude objects in the alternates directory
+	// from being counted towards the total size of the repository.
+	ExcludeAlternates bool
 }
 
 // RepoSizeOption is an option which can be passed to Size
@@ -114,6 +117,13 @@ func WithExcludes(excludes ...string) RepoSizeOption {
 	}
 }
 
+// WithoutAlternates will exclude any objects in the alternate objects directory
+func WithoutAlternates() RepoSizeOption {
+	return func(cfg *repoSizeConfig) {
+		cfg.ExcludeAlternates = true
+	}
+}
+
 // Size calculates the size of all reachable objects in bytes
 func (repo *Repo) Size(ctx context.Context, opts ...RepoSizeOption) (int64, error) {
 	var stdout bytes.Buffer
@@ -132,6 +142,14 @@ func (repo *Repo) Size(ctx context.Context, opts ...RepoSizeOption) (int64, erro
 		)
 	}
 
+	if cfg.ExcludeAlternates {
+		options = append(options,
+			git.Flag{Name: "--not"},
+			git.Flag{Name: "--alternate-refs"},
+			git.Flag{Name: "--not"},
+		)
+	}
+
 	options = append(options,
 		git.Flag{Name: "--all"},
 		git.Flag{Name: "--objects"},
diff --git a/internal/git/localrepo/repo_test.go b/internal/git/localrepo/repo_test.go
index c9f620731..10f87514c 100644
--- a/internal/git/localrepo/repo_test.go
+++ b/internal/git/localrepo/repo_test.go
@@ -207,3 +207,34 @@ func TestSize_excludes(t *testing.T) {
 
 	assert.Equal(t, sizeBeforeKeepAround, sizeWithoutKeepAround)
 }
+
+func TestSize_excludeAlternates(t *testing.T) {
+	cfg := testcfg.Build(t)
+	gitCmdFactory := gittest.NewCommandFactory(t, cfg)
+	catfileCache := catfile.NewCache(cfg)
+	t.Cleanup(catfileCache.Stop)
+	locator := config.NewLocator(cfg)
+
+	pbRepo, repoPath := gittest.CloneRepo(t, cfg, cfg.Storages[0])
+	_, altRepoPath := gittest.CloneRepo(t, cfg, cfg.Storages[0])
+
+	require.NoError(t, os.WriteFile(
+		filepath.Join(repoPath, "objects", "info", "alternates"),
+		[]byte(filepath.Join(altRepoPath, "objects")),
+		os.ModePerm,
+	))
+
+	repo := New(locator, gitCmdFactory, catfileCache, pbRepo)
+
+	ctx := testhelper.Context(t)
+
+	gittest.Exec(t, cfg, "-C", repoPath, "gc")
+
+	sizeIncludingAlternates, err := repo.Size(ctx)
+	require.NoError(t, err)
+	assert.Greater(t, sizeIncludingAlternates, int64(0))
+
+	sizeExcludingAlternates, err := repo.Size(ctx, WithoutAlternates())
+	require.NoError(t, err)
+	assert.Equal(t, int64(0), sizeExcludingAlternates)
+}