Fix for "Worktree Add function adds ".git" directory"

.gitignore

@@ -1 +1,4 @@
 coverage.out
+*~
+coverage.txt
+profile.out

example_test.go

@@ -24,12 +24,18 @@ func ExampleClone() {
 
 	// Clones the repository into the worktree (fs) and storer all the .git
 	// content into the storer
-	_, _ = git.Clone(storer, fs, &git.CloneOptions{
+	_, err := git.Clone(storer, fs, &git.CloneOptions{
 		URL: "https://github.com/git-fixtures/basic.git",
 	})
+	if err != nil {
+		log.Fatal(err)
+	}
 
 	// Prints the content of the CHANGELOG file from the cloned repository
-	changelog, _ := fs.Open("CHANGELOG")
+	changelog, err := fs.Open("CHANGELOG")
+	if err != nil {
+		log.Fatal(err)
+	}
 
 	io.Copy(os.Stdout, changelog)
 	// Output: Initial changelog

repository.go

@@ -24,6 +24,9 @@ import (
 	"gopkg.in/src-d/go-billy.v4/osfs"
 )
 
+// GitDirName this is a special folder where all the git stuff is.
+const GitDirName = ".git"
+
 var (
 	// ErrBranchExists an error stating the specified branch already exists
 	ErrBranchExists = errors.New("branch already exists")
@@ -113,12 +116,12 @@ func createDotGitFile(worktree, storage billy.Filesystem) error {
 		path = storage.Root()
 	}
 
-	if path == ".git" {
+	if path == GitDirName {
 		// not needed, since the folder is the default place
 		return nil
 	}
 
-	f, err := worktree.Create(".git")
+	f, err := worktree.Create(GitDirName)
 	if err != nil {
 		return err
 	}
@@ -214,7 +217,7 @@ func PlainInit(path string, isBare bool) (*Repository, error) {
 		dot = osfs.New(path)
 	} else {
 		wt = osfs.New(path)
-		dot, _ = wt.Chroot(".git")
+		dot, _ = wt.Chroot(GitDirName)
 	}
 
 	s, err := filesystem.NewStorage(dot)
@@ -265,7 +268,7 @@ func dotGitToOSFilesystems(path string, detect bool) (dot, wt billy.Filesystem,
 	var fi os.FileInfo
 	for {
 		fs = osfs.New(path)
-		fi, err = fs.Stat(".git")
+		fi, err = fs.Stat(GitDirName)
 		if err == nil {
 			// no error; stop
 			break
@@ -288,7 +291,7 @@ func dotGitToOSFilesystems(path string, detect bool) (dot, wt billy.Filesystem,
 	}
 
 	if fi.IsDir() {
-		dot, err = fs.Chroot(".git")
+		dot, err = fs.Chroot(GitDirName)
 		return dot, fs, err
 	}
 
@@ -301,7 +304,7 @@ func dotGitToOSFilesystems(path string, detect bool) (dot, wt billy.Filesystem,
 }
 
 func dotGitFileToOSFilesystem(path string, fs billy.Filesystem) (bfs billy.Filesystem, err error) {
-	f, err := fs.Open(".git")
+	f, err := fs.Open(GitDirName)
 	if err != nil {
 		return nil, err
 	}

worktree_status.go

@@ -300,6 +300,10 @@ func (w *Worktree) doAddDirectory(idx *index.Index, s Status, directory string)
 
 		var a bool
 		if file.IsDir() {
+			if file.Name() == GitDirName {
+				// ignore special git directory
+				continue
+			}
 			a, err = w.doAddDirectory(idx, s, name)
 		} else {
 			a, _, err = w.doAddFile(idx, s, name)

worktree_test.go

@@ -3,12 +3,14 @@ package git
 import (
 	"bytes"
 	"context"
+	"errors"
 	"io/ioutil"
 	"os"
 	"path/filepath"
 	"regexp"
 	"runtime"
 	"testing"
+	"time"
 
 	"gopkg.in/src-d/go-git.v4/config"
 	"gopkg.in/src-d/go-git.v4/plumbing"
@@ -1833,3 +1835,39 @@ func (s *WorktreeSuite) TestGrep(c *C) {
 		}
 	}
 }
+
+func (s *WorktreeSuite) TestAddAndCommit(c *C) {
+	dir, err := ioutil.TempDir("", "plain-repo")
+	c.Assert(err, IsNil)
+	defer os.RemoveAll(dir)
+
+	repo, err := PlainInit(dir, false)
+	c.Assert(err, IsNil)
+
+	w, err := repo.Worktree()
+	c.Assert(err, IsNil)
+
+	_, err = w.Add(".")
+	c.Assert(err, IsNil)
+
+	w.Commit("Test Add And Commit", &CommitOptions{Author: &object.Signature{
+		Name:  "foo",
+		Email: "[email protected]",
+		When:  time.Now(),
+	}})
+
+	iter, err := w.r.Log(&LogOptions{})
+	c.Assert(err, IsNil)
+	err = iter.ForEach(func(c *object.Commit) error {
+		files, err := c.Files()
+		if err != nil {
+			return err
+		}
+
+		err = files.ForEach(func(f *object.File) error {
+			return errors.New("Expected no files, got at least 1")
+		})
+		return err
+	})
+	c.Assert(err, IsNil)
+}