Support opening lazygit in a submodule

pkg/commands/git.go

@@ -25,14 +25,11 @@ func verifyInGitRepo(runCmd func(string) error) error {
 
 func navigateToRepoRootDirectory(stat func(string) (os.FileInfo, error), chdir func(string) error) error {
 	for {
-		f, err := stat(".git")
+		_, err := stat(".git")
 
 		if err == nil {
-			if f.IsDir() {
 			return nil
 		}
-			return errors.New("expected .git to be a directory")
-		}
 
 		if !os.IsNotExist(err) {
 			return WrapError(err)
@@ -75,6 +72,7 @@ type GitCommand struct {
 	getGlobalGitConfig func(string) (string, error)
 	getLocalGitConfig  func(string) (string, error)
 	removeFile         func(string) error
+	DotGitDir          string
 }
 
 // NewGitCommand it runs git commands
@@ -102,6 +100,11 @@ func NewGitCommand(log *logrus.Entry, osCommand *OSCommand, tr *i18n.Localizer,
 		}
 	}
 
+	dotGitDir, err := findDotGitDir(os.Stat, ioutil.ReadFile)
+	if err != nil {
+		return nil, err
+	}
+
 	return &GitCommand{
 		Log:                log,
 		OSCommand:          osCommand,
@@ -112,9 +115,31 @@ func NewGitCommand(log *logrus.Entry, osCommand *OSCommand, tr *i18n.Localizer,
 		getGlobalGitConfig: gitconfig.Global,
 		getLocalGitConfig:  gitconfig.Local,
 		removeFile:         os.RemoveAll,
+		DotGitDir:          dotGitDir,
 	}, nil
 }
 
+func findDotGitDir(stat func(string) (os.FileInfo, error), readFile func(filename string) ([]byte, error)) (string, error) {
+	f, err := stat(".git")
+	if err != nil {
+		return "", err
+	}
+
+	if f.IsDir() {
+		return ".git", nil
+	}
+
+	fileBytes, err := readFile(".git")
+	if err != nil {
+		return "", err
+	}
+	fileContent := string(fileBytes)
+	if !strings.HasPrefix(fileContent, "gitdir: ") {
+		return "", errors.New(".git is a file which suggests we are in a submodule but the file's contents do not contain a gitdir pointing to the actual .git directory")
+	}
+	return strings.TrimSpace(strings.TrimPrefix(fileContent, "gitdir: ")), nil
+}
+
 // GetStashEntries stash entryies
 func (c *GitCommand) GetStashEntries() []*StashEntry {
 	rawString, _ := c.OSCommand.RunCommandWithOutput("git stash list --pretty='%gs'")
@@ -426,14 +451,14 @@ func (c *GitCommand) IsInMergeState() (bool, error) {
 // RebaseMode returns "" for non-rebase mode, "normal" for normal rebase
 // and "interactive" for interactive rebase
 func (c *GitCommand) RebaseMode() (string, error) {
-	exists, err := c.OSCommand.FileExists(".git/rebase-apply")
+	exists, err := c.OSCommand.FileExists(fmt.Sprintf("%s/rebase-apply", c.DotGitDir))
 	if err != nil {
 		return "", err
 	}
 	if exists {
 		return "normal", nil
 	}
-	exists, err = c.OSCommand.FileExists(".git/rebase-merge")
+	exists, err = c.OSCommand.FileExists(fmt.Sprintf("%s/rebase-merge", c.DotGitDir))
 	if exists {
 		return "interactive", err
 	} else {
@@ -743,7 +768,7 @@ func (c *GitCommand) AmendTo(sha string) error {
 
 // EditRebaseTodo sets the action at a given index in the git-rebase-todo file
 func (c *GitCommand) EditRebaseTodo(index int, action string) error {
-	fileName := ".git/rebase-merge/git-rebase-todo"
+	fileName := fmt.Sprintf("%s/rebase-merge/git-rebase-todo", c.DotGitDir)
 	bytes, err := ioutil.ReadFile(fileName)
 	if err != nil {
 		return err
@@ -775,7 +800,7 @@ func (c *GitCommand) getTodoCommitCount(content []string) int {
 
 // MoveTodoDown moves a rebase todo item down by one position
 func (c *GitCommand) MoveTodoDown(index int) error {
-	fileName := ".git/rebase-merge/git-rebase-todo"
+	fileName := fmt.Sprintf("%s/rebase-merge/git-rebase-todo", c.DotGitDir)
 	bytes, err := ioutil.ReadFile(fileName)
 	if err != nil {
 		return err

pkg/commands/git_test.go

@@ -8,6 +8,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/go-errors/errors"
 	"github.com/jesseduffield/lazygit/pkg/i18n"
 	"github.com/jesseduffield/lazygit/pkg/test"
 	"github.com/stretchr/testify/assert"
@@ -2122,3 +2123,78 @@ func TestGitCommandCreateFixupCommit(t *testing.T) {
 		})
 	}
 }
+
+func TestFindDotGitDir(t *testing.T) {
+	type scenario struct {
+		testName string
+		stat     func(string) (os.FileInfo, error)
+		readFile func(filename string) ([]byte, error)
+		test     func(string, error)
+	}
+
+	scenarios := []scenario{
+		{
+			".git is a directory",
+			func(dotGit string) (os.FileInfo, error) {
+				assert.Equal(t, ".git", dotGit)
+				return os.Stat("testdata/a_dir")
+			},
+			func(dotGit string) ([]byte, error) {
+				assert.Fail(t, "readFile should not be called if .git is a directory")
+				return nil, nil
+			},
+			func(gitDir string, err error) {
+				assert.NoError(t, err)
+				assert.Equal(t, ".git", gitDir)
+			},
+		},
+		{
+			".git is a file",
+			func(dotGit string) (os.FileInfo, error) {
+				assert.Equal(t, ".git", dotGit)
+				return os.Stat("testdata/a_file")
+			},
+			func(dotGit string) ([]byte, error) {
+				assert.Equal(t, ".git", dotGit)
+				return []byte("gitdir: blah\n"), nil
+			},
+			func(gitDir string, err error) {
+				assert.NoError(t, err)
+				assert.Equal(t, "blah", gitDir)
+			},
+		},
+		{
+			"os.Stat returns an error",
+			func(dotGit string) (os.FileInfo, error) {
+				assert.Equal(t, ".git", dotGit)
+				return nil, errors.New("error")
+			},
+			func(dotGit string) ([]byte, error) {
+				assert.Fail(t, "readFile should not be called os.Stat returns an error")
+				return nil, nil
+			},
+			func(gitDir string, err error) {
+				assert.Error(t, err)
+			},
+		},
+		{
+			"readFile returns an error",
+			func(dotGit string) (os.FileInfo, error) {
+				assert.Equal(t, ".git", dotGit)
+				return os.Stat("testdata/a_file")
+			},
+			func(dotGit string) ([]byte, error) {
+				return nil, errors.New("error")
+			},
+			func(gitDir string, err error) {
+				assert.Error(t, err)
+			},
+		},
+	}
+
+	for _, s := range scenarios {
+		t.Run(s.testName, func(t *testing.T) {
+			s.test(findDotGitDir(s.stat, s.readFile))
+		})
+	}
+}

pkg/git/commit_list_builder.go

@@ -123,7 +123,7 @@ func (c *CommitListBuilder) getRebasingCommits(rebaseMode string) ([]*commands.C
 
 func (c *CommitListBuilder) getNormalRebasingCommits() ([]*commands.Commit, error) {
 	rewrittenCount := 0
-	bytesContent, err := ioutil.ReadFile(".git/rebase-apply/rewritten")
+	bytesContent, err := ioutil.ReadFile(fmt.Sprintf("%s/rebase-apply/rewritten", c.GitCommand.DotGitDir))
 	if err == nil {
 		content := string(bytesContent)
 		rewrittenCount = len(strings.Split(content, "\n"))
@@ -131,7 +131,7 @@ func (c *CommitListBuilder) getNormalRebasingCommits() ([]*commands.Commit, erro
 
 	// we know we're rebasing, so lets get all the files whose names have numbers
 	commits := []*commands.Commit{}
-	err = filepath.Walk(".git/rebase-apply", func(path string, f os.FileInfo, err error) error {
+	err = filepath.Walk(fmt.Sprintf("%s/rebase-apply", c.GitCommand.DotGitDir), func(path string, f os.FileInfo, err error) error {
 		if rewrittenCount > 0 {
 			rewrittenCount--
 			return nil
@@ -175,7 +175,7 @@ func (c *CommitListBuilder) getNormalRebasingCommits() ([]*commands.Commit, erro
 // and extracts out the sha and names of commits that we still have to go
 // in the rebase:
 func (c *CommitListBuilder) getInteractiveRebasingCommits() ([]*commands.Commit, error) {
-	bytesContent, err := ioutil.ReadFile(".git/rebase-merge/git-rebase-todo")
+	bytesContent, err := ioutil.ReadFile(fmt.Sprintf("%s/rebase-merge/git-rebase-todo", c.GitCommand.DotGitDir))
 	if err != nil {
 		c.Log.Info(fmt.Sprintf("error occured reading git-rebase-todo: %s", err.Error()))
 		// we assume an error means the file doesn't exist so we just return