Don't commit when no changes

Author: JohnStarich

vcs/vcs.go

@@ -107,16 +107,39 @@ func (s *syncRepo) CommitFiles(prepFiles func() error, message string, paths ...
 			return err
 		}
 	}
+
+	// relativize paths to repo root
 	rootPath := tree.Filesystem.Root()
-	for _, path := range paths {
-		path, err := filepath.Rel(rootPath, path)
+	for i := range paths {
+		path, err := filepath.Rel(rootPath, paths[i])
 		if err != nil {
 			return err
 		}
+		paths[i] = path
+	}
+
+	for _, path := range paths {
 		if _, err = tree.Add(path); err != nil {
 			return errors.Wrapf(err, "Failed to add %s to the git index", path)
 		}
 	}
+
+	repoStatus, err := tree.Status()
+	if err != nil {
+		return err
+	}
+	shouldCommit := false
+	for _, path := range paths {
+		status, ok := repoStatus[path]
+		if ok && status.Staging != git.Unmodified {
+			shouldCommit = true
+			break
+		}
+	}
+	if !shouldCommit {
+		return nil
+	}
+
 	_, err = tree.Commit(message, &git.CommitOptions{
 		Author: sageAuthor(),
 	})

vcs/vcs_test.go

@@ -86,3 +86,39 @@ func TestCommitFiles(t *testing.T) {
 	require.NoError(t, err)
 	assert.Equal(t, 2, getCount())
 }
+
+func TestCommitNoChanges(t *testing.T) {
+	cleanup := func() {
+		require.NoError(t, os.RemoveAll("./testdb"))
+	}
+	cleanup()
+	defer cleanup()
+
+	repoInt, err := Open("./testdb")
+	require.NoError(t, err)
+	require.IsType(t, &syncRepo{}, repoInt)
+	repo := repoInt.(*syncRepo)
+
+	err = repo.CommitFiles(func() error {
+		return ioutil.WriteFile("./testdb/some file.txt", []byte("hello world"), 0750)
+	}, "add some file", "./testdb/some file.txt")
+	require.NoError(t, err)
+
+	getCount := func() int {
+		count := 0
+		log, err := repo.repo.Log(&git.LogOptions{})
+		require.NoError(t, err)
+
+		err = log.ForEach(func(*object.Commit) error {
+			count++
+			return nil
+		})
+		require.NoError(t, err)
+		return count
+	}
+	assert.Equal(t, 1, getCount())
+
+	err = repo.CommitFiles(func() error { return nil }, "add same file", "./testdb/some file.txt")
+	require.NoError(t, err)
+	assert.Equal(t, 1, getCount(), "no commit should be made for unchanged file")
+}