From 28115d8776a952d9a0c32cf639cdffb2eff19ca2 Mon Sep 17 00:00:00 2001
From: Stefan Majewsky <majewsky@gmx.net>
Date: Fri, 6 Oct 2017 22:35:24 +0200
Subject: fix handling of Git submodules

---
 pkg/prompt/git.go  | 58 +++++++++++++++++++++++++++++++++++++++++++-----------
 pkg/prompt/main.go |  2 +-
 pkg/prompt/pwd.go  | 10 ++++++----
 3 files changed, 53 insertions(+), 17 deletions(-)

diff --git a/pkg/prompt/git.go b/pkg/prompt/git.go
index 054df36..144beb5 100644
--- a/pkg/prompt/git.go
+++ b/pkg/prompt/git.go
@@ -19,30 +19,64 @@
 package prompt
 
 import (
+	"fmt"
 	"io/ioutil"
 	"os"
 	"path/filepath"
 	"strings"
 )
 
-//Returns empty string if `path` is not inside a Git repo.
-func findRepoRootPath(path string) string {
-	_, err := os.Stat(filepath.Join(path, ".git"))
-	if err == nil {
-		return path
+type gitRepo struct {
+	RootPath string
+	GitDir   string
+}
+
+//Returns two empty strings if `path` is not inside a Git repo.
+func findRepo(path string) (*gitRepo, error) {
+	//find .git directory or file
+	gitEntry := filepath.Join(path, ".git")
+	fi, err := os.Stat(gitEntry)
+	switch {
+	case err == nil:
+		//found - continue below with further checks
+	case !os.IsNotExist(err):
+		return nil, err
+	case path == "/":
+		return nil, nil
+	default:
+		return findRepo(filepath.Dir(path))
 	}
-	if path == "/" {
-		return ""
+
+	//found .git - what is it?
+	if fi.Mode().IsDir() {
+		//normal case - .git is a directory
+		return &gitRepo{RootPath: path, GitDir: gitEntry}, nil
+	}
+
+	//.git is a file (e.g. for submodules) - it contains a line like "gitdir: path/to/gitdir"
+	bytes, err := ioutil.ReadFile(gitEntry)
+	if err != nil {
+		return nil, err
 	}
-	return findRepoRootPath(filepath.Dir(path))
+	for _, line := range strings.Split(string(bytes), "\n") {
+		line = strings.TrimSpace(line)
+		if strings.HasPrefix(line, "gitdir:") {
+			return &gitRepo{
+				RootPath: path,
+				GitDir:   filepath.Join(path, strings.TrimSpace(strings.TrimPrefix(line, "gitdir:"))),
+			}, nil
+		}
+	}
+
+	return nil, fmt.Errorf("read %s: missing gitdir directive", gitEntry)
 }
 
-func getRepoStatusField(repoRootPath string) string {
-	if repoRootPath == "" {
+func getRepoStatusField(repo *gitRepo) string {
+	if repo == nil {
 		return ""
 	}
 
-	bytes, err := ioutil.ReadFile(filepath.Join(repoRootPath, ".git/HEAD"))
+	bytes, err := ioutil.ReadFile(filepath.Join(repo.GitDir, "HEAD"))
 	if err != nil {
 		handleError(err)
 		return withType("git", withColor("1;41", "unknown"))
@@ -60,7 +94,7 @@ func getRepoStatusField(repoRootPath string) string {
 	refSpecDisplay = strings.TrimPrefix(refSpecDisplay, "heads/")
 
 	//read file corresponding to refspec to find commit
-	bytes, err = ioutil.ReadFile(filepath.Join(repoRootPath, ".git", refSpec))
+	bytes, err = ioutil.ReadFile(filepath.Join(repo.GitDir, refSpec))
 	commitID := strings.TrimSpace(string(bytes))
 	if err != nil {
 		if os.IsNotExist(err) {
diff --git a/pkg/prompt/main.go b/pkg/prompt/main.go
index 1dcbbc7..1fc60d9 100644
--- a/pkg/prompt/main.go
+++ b/pkg/prompt/main.go
@@ -37,7 +37,7 @@ func Exec(args []string) int {
 	cwd := CurrentDirectory()
 	fields = appendUnlessEmpty(fields, getDirectoryField(cwd))
 	fields = appendUnlessEmpty(fields, getDeletedMessageField(cwd))
-	fields = appendUnlessEmpty(fields, getRepoStatusField(cwd.RepoRootPath))
+	fields = appendUnlessEmpty(fields, getRepoStatusField(cwd.Repo))
 	fields = appendUnlessEmpty(fields, getTerminalField())
 	fields = appendUnlessEmpty(fields, getOpenstackField())
 	fields = appendUnlessEmpty(fields, getKubernetesField())
diff --git a/pkg/prompt/pwd.go b/pkg/prompt/pwd.go
index 969a8ce..1b93987 100644
--- a/pkg/prompt/pwd.go
+++ b/pkg/prompt/pwd.go
@@ -30,7 +30,7 @@ type Directory struct {
 	DisplayPath           string
 	InBuildTree           bool
 	InRepoTree            bool
-	RepoRootPath          string
+	Repo                  *gitRepo
 	NearestAccessiblePath string
 }
 
@@ -78,7 +78,9 @@ func NewDirectory(path string) (dir Directory) {
 		dir.stripHomeDirFromDisplay()
 
 		//check if we are inside a Git repository
-		dir.RepoRootPath = findRepoRootPath(dir.Path)
+		var err error
+		dir.Repo, err = findRepo(dir.Path)
+		handleError(err)
 	}
 
 	return
@@ -124,8 +126,8 @@ func getDirectoryField(dir Directory) string {
 	txt := withColor("1;36", dir.DisplayPath)
 	if dir.NearestAccessiblePath == "" {
 		//cwd accessible -> highlight path elements inside the repo (if any)
-		if dir.RepoRootPath != "" && dir.RepoRootPath != dir.Path {
-			rel, _ := filepath.Rel(dir.RepoRootPath, dir.Path)
+		if dir.Repo != nil && dir.Repo.RootPath != dir.Path {
+			rel, _ := filepath.Rel(dir.Repo.RootPath, dir.Path)
 			if strings.HasSuffix(dir.DisplayPath, rel) {
 				base := strings.TrimSuffix(dir.DisplayPath, rel)
 				txt = withColor("0;36", base) + withColor("1;36", rel)
-- 
cgit v1.3.1