From edc94c70413048107ea728ff330f32ca3de6df88 Mon Sep 17 00:00:00 2001
From: Lunny Xiao <xiaolunwen@gmail.com>
Date: Thu, 27 Jun 2019 02:15:26 +0800
Subject: [PATCH] Monitor all git commands; move blame to git package and
 replace git as a variable (#6864)

* monitor all git commands; move blame to git package and replace git as a variable

* use git command but not other commands

* fix build

* move exec.Command to git.NewCommand

* fix fmt

* remove unrelated changes

* remove unrelated changes

* refactor IsEmpty and add tests

* fix tests

* fix tests

* fix tests

* fix tests

* remove gitLogger

* fix fmt

* fix isEmpty

* fix lint

* fix tests
---
 contrib/pr/checkout.go                        |   6 +-
 models/git_diff.go                            |  16 +-
 models/pull.go                                |   8 +-
 models/release.go                             |   2 +-
 models/repo.go                                |  34 ++--
 models/repo_mirror.go                         |   4 +-
 models/update.go                              |   6 +-
 models/git_blame.go => modules/git/blame.go   |   7 +-
 .../git/blame_test.go                         |   2 +-
 modules/git/command.go                        |   5 +
 modules/git/repo.go                           |  14 ++
 modules/git/repo_test.go                      |  10 ++
 modules/git/tests/repos/repo2_empty/HEAD      |   1 +
 modules/git/tests/repos/repo2_empty/config    |   6 +
 .../git/tests/repos/repo2_empty/description   |   1 +
 .../repo2_empty/hooks/applypatch-msg.sample   |  15 ++
 .../repos/repo2_empty/hooks/commit-msg.sample |  24 +++
 .../hooks/fsmonitor-watchman.sample           | 114 ++++++++++++
 .../repo2_empty/hooks/post-update.sample      |   8 +
 .../repo2_empty/hooks/pre-applypatch.sample   |  14 ++
 .../repos/repo2_empty/hooks/pre-commit.sample |  49 +++++
 .../repos/repo2_empty/hooks/pre-push.sample   |  53 ++++++
 .../repos/repo2_empty/hooks/pre-rebase.sample | 169 ++++++++++++++++++
 .../repo2_empty/hooks/pre-receive.sample      |  24 +++
 .../hooks/prepare-commit-msg.sample           |  42 +++++
 .../repos/repo2_empty/hooks/update.sample     | 128 +++++++++++++
 .../git/tests/repos/repo2_empty/info/exclude  |   6 +
 .../repos/repo2_empty/objects/info/.gitkeep   |   0
 .../repos/repo2_empty/objects/pack/.gitkeep   |   0
 .../repos/repo2_empty/refs/heads/.gitkeep     |   0
 .../repos/repo2_empty/refs/tags/.gitkeep      |   0
 modules/repofiles/temp_repo.go                |  24 +--
 routers/repo/blame.go                         |   6 +-
 routers/repo/http.go                          |  26 +--
 34 files changed, 750 insertions(+), 74 deletions(-)
 rename models/git_blame.go => modules/git/blame.go (93%)
 rename models/git_blame_test.go => modules/git/blame_test.go (99%)
 create mode 100644 modules/git/tests/repos/repo2_empty/HEAD
 create mode 100644 modules/git/tests/repos/repo2_empty/config
 create mode 100644 modules/git/tests/repos/repo2_empty/description
 create mode 100755 modules/git/tests/repos/repo2_empty/hooks/applypatch-msg.sample
 create mode 100755 modules/git/tests/repos/repo2_empty/hooks/commit-msg.sample
 create mode 100755 modules/git/tests/repos/repo2_empty/hooks/fsmonitor-watchman.sample
 create mode 100755 modules/git/tests/repos/repo2_empty/hooks/post-update.sample
 create mode 100755 modules/git/tests/repos/repo2_empty/hooks/pre-applypatch.sample
 create mode 100755 modules/git/tests/repos/repo2_empty/hooks/pre-commit.sample
 create mode 100755 modules/git/tests/repos/repo2_empty/hooks/pre-push.sample
 create mode 100755 modules/git/tests/repos/repo2_empty/hooks/pre-rebase.sample
 create mode 100755 modules/git/tests/repos/repo2_empty/hooks/pre-receive.sample
 create mode 100755 modules/git/tests/repos/repo2_empty/hooks/prepare-commit-msg.sample
 create mode 100755 modules/git/tests/repos/repo2_empty/hooks/update.sample
 create mode 100644 modules/git/tests/repos/repo2_empty/info/exclude
 create mode 100644 modules/git/tests/repos/repo2_empty/objects/info/.gitkeep
 create mode 100644 modules/git/tests/repos/repo2_empty/objects/pack/.gitkeep
 create mode 100644 modules/git/tests/repos/repo2_empty/refs/heads/.gitkeep
 create mode 100644 modules/git/tests/repos/repo2_empty/refs/tags/.gitkeep

diff --git a/contrib/pr/checkout.go b/contrib/pr/checkout.go
index a837cb581..4b39c8e9f 100644
--- a/contrib/pr/checkout.go
+++ b/contrib/pr/checkout.go
@@ -20,10 +20,13 @@ import (
 	"strconv"
 	"time"
 
+	"code.gitea.io/gitea/models"
 	"code.gitea.io/gitea/modules/markup"
 	"code.gitea.io/gitea/modules/markup/external"
+	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/routers"
 	"code.gitea.io/gitea/routers/routes"
+
 	"github.com/Unknwon/com"
 	"github.com/go-xorm/xorm"
 	context2 "github.com/gorilla/context"
@@ -31,9 +34,6 @@ import (
 	"gopkg.in/src-d/go-git.v4/config"
 	"gopkg.in/src-d/go-git.v4/plumbing"
 	"gopkg.in/testfixtures.v2"
-
-	"code.gitea.io/gitea/models"
-	"code.gitea.io/gitea/modules/setting"
 )
 
 var codeFilePath = "contrib/pr/checkout.go"
diff --git a/models/git_diff.go b/models/git_diff.go
index 29c424c11..bc79a73a4 100644
--- a/models/git_diff.go
+++ b/models/git_diff.go
@@ -675,7 +675,7 @@ func GetDiffRangeWithWhitespaceBehavior(repoPath, beforeCommitID, afterCommitID
 
 	var cmd *exec.Cmd
 	if len(beforeCommitID) == 0 && commit.ParentCount() == 0 {
-		cmd = exec.Command("git", "show", afterCommitID)
+		cmd = exec.Command(git.GitExecutable, "show", afterCommitID)
 	} else {
 		actualBeforeCommitID := beforeCommitID
 		if len(actualBeforeCommitID) == 0 {
@@ -688,7 +688,7 @@ func GetDiffRangeWithWhitespaceBehavior(repoPath, beforeCommitID, afterCommitID
 		}
 		diffArgs = append(diffArgs, actualBeforeCommitID)
 		diffArgs = append(diffArgs, afterCommitID)
-		cmd = exec.Command("git", diffArgs...)
+		cmd = exec.Command(git.GitExecutable, diffArgs...)
 	}
 	cmd.Dir = repoPath
 	cmd.Stderr = os.Stderr
@@ -752,23 +752,23 @@ func GetRawDiffForFile(repoPath, startCommit, endCommit string, diffType RawDiff
 	switch diffType {
 	case RawDiffNormal:
 		if len(startCommit) != 0 {
-			cmd = exec.Command("git", append([]string{"diff", "-M", startCommit, endCommit}, fileArgs...)...)
+			cmd = exec.Command(git.GitExecutable, append([]string{"diff", "-M", startCommit, endCommit}, fileArgs...)...)
 		} else if commit.ParentCount() == 0 {
-			cmd = exec.Command("git", append([]string{"show", endCommit}, fileArgs...)...)
+			cmd = exec.Command(git.GitExecutable, append([]string{"show", endCommit}, fileArgs...)...)
 		} else {
 			c, _ := commit.Parent(0)
-			cmd = exec.Command("git", append([]string{"diff", "-M", c.ID.String(), endCommit}, fileArgs...)...)
+			cmd = exec.Command(git.GitExecutable, append([]string{"diff", "-M", c.ID.String(), endCommit}, fileArgs...)...)
 		}
 	case RawDiffPatch:
 		if len(startCommit) != 0 {
 			query := fmt.Sprintf("%s...%s", endCommit, startCommit)
-			cmd = exec.Command("git", append([]string{"format-patch", "--no-signature", "--stdout", "--root", query}, fileArgs...)...)
+			cmd = exec.Command(git.GitExecutable, append([]string{"format-patch", "--no-signature", "--stdout", "--root", query}, fileArgs...)...)
 		} else if commit.ParentCount() == 0 {
-			cmd = exec.Command("git", append([]string{"format-patch", "--no-signature", "--stdout", "--root", endCommit}, fileArgs...)...)
+			cmd = exec.Command(git.GitExecutable, append([]string{"format-patch", "--no-signature", "--stdout", "--root", endCommit}, fileArgs...)...)
 		} else {
 			c, _ := commit.Parent(0)
 			query := fmt.Sprintf("%s...%s", endCommit, c.ID.String())
-			cmd = exec.Command("git", append([]string{"format-patch", "--no-signature", "--stdout", query}, fileArgs...)...)
+			cmd = exec.Command(git.GitExecutable, append([]string{"format-patch", "--no-signature", "--stdout", query}, fileArgs...)...)
 		}
 	default:
 		return fmt.Errorf("invalid diffType: %s", diffType)
diff --git a/models/pull.go b/models/pull.go
index 38976d37e..2f5412651 100644
--- a/models/pull.go
+++ b/models/pull.go
@@ -463,7 +463,7 @@ func (pr *PullRequest) getMergeCommit() (*git.Commit, error) {
 	// Check if a pull request is merged into BaseBranch
 	_, stderr, err := process.GetManager().ExecDirEnv(-1, "", fmt.Sprintf("isMerged (git merge-base --is-ancestor): %d", pr.BaseRepo.ID),
 		[]string{"GIT_INDEX_FILE=" + indexTmpPath, "GIT_DIR=" + pr.BaseRepo.RepoPath()},
-		"git", "merge-base", "--is-ancestor", headFile, pr.BaseBranch)
+		git.GitExecutable, "merge-base", "--is-ancestor", headFile, pr.BaseBranch)
 
 	if err != nil {
 		// Errors are signaled by a non-zero status that is not 1
@@ -486,7 +486,7 @@ func (pr *PullRequest) getMergeCommit() (*git.Commit, error) {
 	// Get the commit from BaseBranch where the pull request got merged
 	mergeCommit, stderr, err := process.GetManager().ExecDirEnv(-1, "", fmt.Sprintf("isMerged (git rev-list --ancestry-path --merges --reverse): %d", pr.BaseRepo.ID),
 		[]string{"GIT_INDEX_FILE=" + indexTmpPath, "GIT_DIR=" + pr.BaseRepo.RepoPath()},
-		"git", "rev-list", "--ancestry-path", "--merges", "--reverse", cmd)
+		git.GitExecutable, "rev-list", "--ancestry-path", "--merges", "--reverse", cmd)
 	if err != nil {
 		return nil, fmt.Errorf("git rev-list --ancestry-path --merges --reverse: %v %v", stderr, err)
 	} else if len(mergeCommit) < 40 {
@@ -548,7 +548,7 @@ func (pr *PullRequest) testPatch(e Engine) (err error) {
 	var stderr string
 	_, stderr, err = process.GetManager().ExecDirEnv(-1, "", fmt.Sprintf("testPatch (git read-tree): %d", pr.BaseRepo.ID),
 		[]string{"GIT_DIR=" + pr.BaseRepo.RepoPath(), "GIT_INDEX_FILE=" + indexTmpPath},
-		"git", "read-tree", pr.BaseBranch)
+		git.GitExecutable, "read-tree", pr.BaseBranch)
 	if err != nil {
 		return fmt.Errorf("git read-tree --index-output=%s %s: %v - %s", indexTmpPath, pr.BaseBranch, err, stderr)
 	}
@@ -568,7 +568,7 @@ func (pr *PullRequest) testPatch(e Engine) (err error) {
 
 	_, stderr, err = process.GetManager().ExecDirEnv(-1, "", fmt.Sprintf("testPatch (git apply --check): %d", pr.BaseRepo.ID),
 		[]string{"GIT_INDEX_FILE=" + indexTmpPath, "GIT_DIR=" + pr.BaseRepo.RepoPath()},
-		"git", args...)
+		git.GitExecutable, args...)
 	if err != nil {
 		for i := range patchConflicts {
 			if strings.Contains(stderr, patchConflicts[i]) {
diff --git a/models/release.go b/models/release.go
index 036b5f78b..f8e8c17e7 100644
--- a/models/release.go
+++ b/models/release.go
@@ -434,7 +434,7 @@ func DeleteReleaseByID(id int64, u *User, delTag bool) error {
 	if delTag {
 		_, stderr, err := process.GetManager().ExecDir(-1, repo.RepoPath(),
 			fmt.Sprintf("DeleteReleaseByID (git tag -d): %d", rel.ID),
-			"git", "tag", "-d", rel.TagName)
+			git.GitExecutable, "tag", "-d", rel.TagName)
 		if err != nil && !strings.Contains(stderr, "not found") {
 			return fmt.Errorf("git tag -d: %v - %s", err, stderr)
 		}
diff --git a/models/repo.go b/models/repo.go
index 2f732d0e2..1b4ff1f18 100644
--- a/models/repo.go
+++ b/models/repo.go
@@ -932,22 +932,18 @@ func MigrateRepository(doer, u *User, opts MigrateRepoOptions) (*Repository, err
 		}
 	}
 
-	// Check if repository is empty.
-	_, stderr, err := com.ExecCmdDir(repoPath, "git", "log", "-1")
+	gitRepo, err := git.OpenRepository(repoPath)
 	if err != nil {
-		if strings.Contains(stderr, "fatal: bad default revision 'HEAD'") {
-			repo.IsEmpty = true
-		} else {
-			return repo, fmt.Errorf("check empty: %v - %s", err, stderr)
-		}
+		return repo, fmt.Errorf("OpenRepository: %v", err)
+	}
+
+	repo.IsEmpty, err = gitRepo.IsEmpty()
+	if err != nil {
+		return repo, fmt.Errorf("git.IsEmpty: %v", err)
 	}
 
 	if !repo.IsEmpty {
 		// Try to get HEAD branch and set it as default branch.
-		gitRepo, err := git.OpenRepository(repoPath)
-		if err != nil {
-			return repo, fmt.Errorf("OpenRepository: %v", err)
-		}
 		headBranch, err := gitRepo.GetHEADBranch()
 		if err != nil {
 			return repo, fmt.Errorf("GetHEADBranch: %v", err)
@@ -1072,20 +1068,20 @@ func initRepoCommit(tmpPath string, sig *git.Signature) (err error) {
 	var stderr string
 	if _, stderr, err = process.GetManager().ExecDir(-1,
 		tmpPath, fmt.Sprintf("initRepoCommit (git add): %s", tmpPath),
-		"git", "add", "--all"); err != nil {
+		git.GitExecutable, "add", "--all"); err != nil {
 		return fmt.Errorf("git add: %s", stderr)
 	}
 
 	if _, stderr, err = process.GetManager().ExecDir(-1,
 		tmpPath, fmt.Sprintf("initRepoCommit (git commit): %s", tmpPath),
-		"git", "commit", fmt.Sprintf("--author='%s <%s>'", sig.Name, sig.Email),
+		git.GitExecutable, "commit", fmt.Sprintf("--author='%s <%s>'", sig.Name, sig.Email),
 		"-m", "Initial commit"); err != nil {
 		return fmt.Errorf("git commit: %s", stderr)
 	}
 
 	if _, stderr, err = process.GetManager().ExecDir(-1,
 		tmpPath, fmt.Sprintf("initRepoCommit (git push): %s", tmpPath),
-		"git", "push", "origin", "master"); err != nil {
+		git.GitExecutable, "push", "origin", "master"); err != nil {
 		return fmt.Errorf("git push: %s", stderr)
 	}
 	return nil
@@ -1131,7 +1127,7 @@ func prepareRepoCommit(e Engine, repo *Repository, tmpDir, repoPath string, opts
 	// Clone to temporary path and do the init commit.
 	_, stderr, err := process.GetManager().Exec(
 		fmt.Sprintf("initRepository(git clone): %s", repoPath),
-		"git", "clone", repoPath, tmpDir,
+		git.GitExecutable, "clone", repoPath, tmpDir,
 	)
 	if err != nil {
 		return fmt.Errorf("git clone: %v - %s", err, stderr)
@@ -1390,7 +1386,7 @@ func CreateRepository(doer, u *User, opts CreateRepoOptions) (_ *Repository, err
 
 		_, stderr, err := process.GetManager().ExecDir(-1,
 			repoPath, fmt.Sprintf("CreateRepository(git update-server-info): %s", repoPath),
-			"git", "update-server-info")
+			git.GitExecutable, "update-server-info")
 		if err != nil {
 			return nil, errors.New("CreateRepository(git update-server-info): " + stderr)
 		}
@@ -2239,7 +2235,7 @@ func GitGcRepos() error {
 				_, stderr, err := process.GetManager().ExecDir(
 					time.Duration(setting.Git.Timeout.GC)*time.Second,
 					RepoPath(repo.Owner.Name, repo.Name), "Repository garbage collection",
-					"git", args...)
+					git.GitExecutable, args...)
 				if err != nil {
 					return fmt.Errorf("%v: %v", err, stderr)
 				}
@@ -2429,14 +2425,14 @@ func ForkRepository(doer, u *User, oldRepo *Repository, name, desc string) (_ *R
 	repoPath := RepoPath(u.Name, repo.Name)
 	_, stderr, err := process.GetManager().ExecTimeout(10*time.Minute,
 		fmt.Sprintf("ForkRepository(git clone): %s/%s", u.Name, repo.Name),
-		"git", "clone", "--bare", oldRepo.repoPath(sess), repoPath)
+		git.GitExecutable, "clone", "--bare", oldRepo.repoPath(sess), repoPath)
 	if err != nil {
 		return nil, fmt.Errorf("git clone: %v", stderr)
 	}
 
 	_, stderr, err = process.GetManager().ExecDir(-1,
 		repoPath, fmt.Sprintf("ForkRepository(git update-server-info): %s", repoPath),
-		"git", "update-server-info")
+		git.GitExecutable, "update-server-info")
 	if err != nil {
 		return nil, fmt.Errorf("git update-server-info: %v", stderr)
 	}
diff --git a/models/repo_mirror.go b/models/repo_mirror.go
index 7579231d8..c62834f6f 100644
--- a/models/repo_mirror.go
+++ b/models/repo_mirror.go
@@ -216,7 +216,7 @@ func (m *Mirror) runSync() ([]*mirrorSyncResult, bool) {
 
 	_, stderr, err := process.GetManager().ExecDir(
 		timeout, repoPath, fmt.Sprintf("Mirror.runSync: %s", repoPath),
-		"git", gitArgs...)
+		git.GitExecutable, gitArgs...)
 	if err != nil {
 		// sanitize the output, since it may contain the remote address, which may
 		// contain a password
@@ -250,7 +250,7 @@ func (m *Mirror) runSync() ([]*mirrorSyncResult, bool) {
 	if m.Repo.HasWiki() {
 		if _, stderr, err := process.GetManager().ExecDir(
 			timeout, wikiPath, fmt.Sprintf("Mirror.runSync: %s", wikiPath),
-			"git", "remote", "update", "--prune"); err != nil {
+			git.GitExecutable, "remote", "update", "--prune"); err != nil {
 			// sanitize the output, since it may contain the remote address, which may
 			// contain a password
 			message, err := sanitizeOutput(stderr, wikiPath)
diff --git a/models/update.go b/models/update.go
index 3eb0990d3..411f7d5be 100644
--- a/models/update.go
+++ b/models/update.go
@@ -7,7 +7,6 @@ package models
 import (
 	"container/list"
 	"fmt"
-	"os/exec"
 	"strings"
 	"time"
 
@@ -193,9 +192,8 @@ func pushUpdate(opts PushUpdateOptions) (repo *Repository, err error) {
 
 	repoPath := RepoPath(opts.RepoUserName, opts.RepoName)
 
-	gitUpdate := exec.Command("git", "update-server-info")
-	gitUpdate.Dir = repoPath
-	if err = gitUpdate.Run(); err != nil {
+	_, err = git.NewCommand("update-server-info").RunInDir(repoPath)
+	if err != nil {
 		return nil, fmt.Errorf("Failed to call 'git update-server-info': %v", err)
 	}
 
diff --git a/models/git_blame.go b/modules/git/blame.go
similarity index 93%
rename from models/git_blame.go
rename to modules/git/blame.go
index 2b439a23b..548236b65 100644
--- a/models/git_blame.go
+++ b/modules/git/blame.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a MIT-style
 // license that can be found in the LICENSE file.
 
-package models
+package git
 
 import (
 	"bufio"
@@ -12,7 +12,6 @@ import (
 	"os/exec"
 	"regexp"
 
-	"code.gitea.io/gitea/modules/git"
 	"code.gitea.io/gitea/modules/process"
 )
 
@@ -88,12 +87,12 @@ func (r *BlameReader) Close() error {
 
 // CreateBlameReader creates reader for given repository, commit and file
 func CreateBlameReader(repoPath, commitID, file string) (*BlameReader, error) {
-	_, err := git.OpenRepository(repoPath)
+	_, err := OpenRepository(repoPath)
 	if err != nil {
 		return nil, err
 	}
 
-	return createBlameReader(repoPath, "git", "blame", commitID, "--porcelain", "--", file)
+	return createBlameReader(repoPath, GitExecutable, "blame", commitID, "--porcelain", "--", file)
 }
 
 func createBlameReader(dir string, command ...string) (*BlameReader, error) {
diff --git a/models/git_blame_test.go b/modules/git/blame_test.go
similarity index 99%
rename from models/git_blame_test.go
rename to modules/git/blame_test.go
index eb0b35380..1752312d8 100644
--- a/models/git_blame_test.go
+++ b/modules/git/blame_test.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a MIT-style
 // license that can be found in the LICENSE file.
 
-package models
+package git
 
 import (
 	"io/ioutil"
diff --git a/modules/git/command.go b/modules/git/command.go
index d6221ce26..347dcfe39 100644
--- a/modules/git/command.go
+++ b/modules/git/command.go
@@ -12,6 +12,8 @@ import (
 	"os/exec"
 	"strings"
 	"time"
+
+	"code.gitea.io/gitea/modules/process"
 )
 
 var (
@@ -84,6 +86,9 @@ func (c *Command) RunInDirTimeoutEnvFullPipeline(env []string, timeout time.Dura
 		return err
 	}
 
+	pid := process.GetManager().Add(fmt.Sprintf("%s %s %s [repo_path: %s]", GitExecutable, c.name, strings.Join(c.args, " "), dir), cmd)
+	defer process.GetManager().Remove(pid)
+
 	if err := cmd.Wait(); err != nil {
 		return err
 	}
diff --git a/modules/git/repo.go b/modules/git/repo.go
index f5d7ee63b..8a40fb1b9 100644
--- a/modules/git/repo.go
+++ b/modules/git/repo.go
@@ -107,6 +107,20 @@ func OpenRepository(repoPath string) (*Repository, error) {
 	}, nil
 }
 
+// IsEmpty Check if repository is empty.
+func (repo *Repository) IsEmpty() (bool, error) {
+	var errbuf strings.Builder
+	if err := NewCommand("log", "-1").RunInDirPipeline(repo.Path, nil, &errbuf); err != nil {
+		if strings.Contains(errbuf.String(), "fatal: bad default revision 'HEAD'") ||
+			strings.Contains(errbuf.String(), "fatal: your current branch 'master' does not have any commits yet") {
+			return true, nil
+		}
+		return true, fmt.Errorf("check empty: %v - %s", err, errbuf.String())
+	}
+
+	return false, nil
+}
+
 // CloneRepoOptions options when clone a repository
 type CloneRepoOptions struct {
 	Timeout    time.Duration
diff --git a/modules/git/repo_test.go b/modules/git/repo_test.go
index c5ce6f444..15f5e3781 100644
--- a/modules/git/repo_test.go
+++ b/modules/git/repo_test.go
@@ -5,6 +5,7 @@
 package git
 
 import (
+	"path/filepath"
 	"testing"
 	"time"
 
@@ -24,3 +25,12 @@ func TestGetLatestCommitTime(t *testing.T) {
 	assert.NoError(t, err)
 	assert.True(t, lct.Unix() > refTime.Unix(), "%d not greater than %d", lct, refTime)
 }
+
+func TestRepoIsEmpty(t *testing.T) {
+	emptyRepo2Path := filepath.Join(testReposDir, "repo2_empty")
+	repo, err := OpenRepository(emptyRepo2Path)
+	assert.NoError(t, err)
+	isEmpty, err := repo.IsEmpty()
+	assert.NoError(t, err)
+	assert.True(t, isEmpty)
+}
diff --git a/modules/git/tests/repos/repo2_empty/HEAD b/modules/git/tests/repos/repo2_empty/HEAD
new file mode 100644
index 000000000..cb089cd89
--- /dev/null
+++ b/modules/git/tests/repos/repo2_empty/HEAD
@@ -0,0 +1 @@
+ref: refs/heads/master
diff --git a/modules/git/tests/repos/repo2_empty/config b/modules/git/tests/repos/repo2_empty/config
new file mode 100644
index 000000000..e6da23157
--- /dev/null
+++ b/modules/git/tests/repos/repo2_empty/config
@@ -0,0 +1,6 @@
+[core]
+	repositoryformatversion = 0
+	filemode = true
+	bare = true
+	ignorecase = true
+	precomposeunicode = true
diff --git a/modules/git/tests/repos/repo2_empty/description b/modules/git/tests/repos/repo2_empty/description
new file mode 100644
index 000000000..498b267a8
--- /dev/null
+++ b/modules/git/tests/repos/repo2_empty/description
@@ -0,0 +1 @@
+Unnamed repository; edit this file 'description' to name the repository.
diff --git a/modules/git/tests/repos/repo2_empty/hooks/applypatch-msg.sample b/modules/git/tests/repos/repo2_empty/hooks/applypatch-msg.sample
new file mode 100755
index 000000000..a5d7b84a6
--- /dev/null
+++ b/modules/git/tests/repos/repo2_empty/hooks/applypatch-msg.sample
@@ -0,0 +1,15 @@
+#!/bin/sh
+#
+# An example hook script to check the commit log message taken by
+# applypatch from an e-mail message.
+#
+# The hook should exit with non-zero status after issuing an
+# appropriate message if it wants to stop the commit.  The hook is
+# allowed to edit the commit message file.
+#
+# To enable this hook, rename this file to "applypatch-msg".
+
+. git-sh-setup
+commitmsg="$(git rev-parse --git-path hooks/commit-msg)"
+test -x "$commitmsg" && exec "$commitmsg" ${1+"$@"}
+:
diff --git a/modules/git/tests/repos/repo2_empty/hooks/commit-msg.sample b/modules/git/tests/repos/repo2_empty/hooks/commit-msg.sample
new file mode 100755
index 000000000..b58d1184a
--- /dev/null
+++ b/modules/git/tests/repos/repo2_empty/hooks/commit-msg.sample
@@ -0,0 +1,24 @@
+#!/bin/sh
+#
+# An example hook script to check the commit log message.
+# Called by "git commit" with one argument, the name of the file
+# that has the commit message.  The hook should exit with non-zero
+# status after issuing an appropriate message if it wants to stop the
+# commit.  The hook is allowed to edit the commit message file.
+#
+# To enable this hook, rename this file to "commit-msg".
+
+# Uncomment the below to add a Signed-off-by line to the message.
+# Doing this in a hook is a bad idea in general, but the prepare-commit-msg
+# hook is more suited to it.
+#
+# SOB=$(git var GIT_AUTHOR_IDENT | sed -n 's/^\(.*>\).*$/Signed-off-by: \1/p')
+# grep -qs "^$SOB" "$1" || echo "$SOB" >> "$1"
+
+# This example catches duplicate Signed-off-by lines.
+
+test "" = "$(grep '^Signed-off-by: ' "$1" |
+	 sort | uniq -c | sed -e '/^[ 	]*1[ 	]/d')" || {
+	echo >&2 Duplicate Signed-off-by lines.
+	exit 1
+}
diff --git a/modules/git/tests/repos/repo2_empty/hooks/fsmonitor-watchman.sample b/modules/git/tests/repos/repo2_empty/hooks/fsmonitor-watchman.sample
new file mode 100755
index 000000000..e673bb398
--- /dev/null
+++ b/modules/git/tests/repos/repo2_empty/hooks/fsmonitor-watchman.sample
@@ -0,0 +1,114 @@
+#!/usr/bin/perl
+
+use strict;
+use warnings;
+use IPC::Open2;
+
+# An example hook script to integrate Watchman
+# (https://facebook.github.io/watchman/) with git to speed up detecting
+# new and modified files.
+#
+# The hook is passed a version (currently 1) and a time in nanoseconds
+# formatted as a string and outputs to stdout all files that have been
+# modified since the given time. Paths must be relative to the root of
+# the working tree and separated by a single NUL.
+#
+# To enable this hook, rename this file to "query-watchman" and set
+# 'git config core.fsmonitor .git/hooks/query-watchman'
+#
+my ($version, $time) = @ARGV;
+
+# Check the hook interface version
+
+if ($version == 1) {
+	# convert nanoseconds to seconds
+	$time = int $time / 1000000000;
+} else {
+	die "Unsupported query-fsmonitor hook version '$version'.\n" .
+	    "Falling back to scanning...\n";
+}
+
+my $git_work_tree;
+if ($^O =~ 'msys' || $^O =~ 'cygwin') {
+	$git_work_tree = Win32::GetCwd();
+	$git_work_tree =~ tr/\\/\//;
+} else {
+	require Cwd;
+	$git_work_tree = Cwd::cwd();
+}
+
+my $retry = 1;
+
+launch_watchman();
+
+sub launch_watchman {
+
+	my $pid = open2(\*CHLD_OUT, \*CHLD_IN, 'watchman -j --no-pretty')
+	    or die "open2() failed: $!\n" .
+	    "Falling back to scanning...\n";
+
+	# In the query expression below we're asking for names of files that
+	# changed since $time but were not transient (ie created after
+	# $time but no longer exist).
+	#
+	# To accomplish this, we're using the "since" generator to use the
+	# recency index to select candidate nodes and "fields" to limit the
+	# output to file names only. Then we're using the "expression" term to
+	# further constrain the results.
+	#
+	# The category of transient files that we want to ignore will have a
+	# creation clock (cclock) newer than $time_t value and will also not
+	# currently exist.
+
+	my $query = <<"	END";
+		["query", "$git_work_tree", {
+			"since": $time,
+			"fields": ["name"],
+			"expression": ["not", ["allof", ["since", $time, "cclock"], ["not", "exists"]]]
+		}]
+	END
+
+	print CHLD_IN $query;
+	close CHLD_IN;
+	my $response = do {local $/; <CHLD_OUT>};
+
+	die "Watchman: command returned no output.\n" .
+	    "Falling back to scanning...\n" if $response eq "";
+	die "Watchman: command returned invalid output: $response\n" .
+	    "Falling back to scanning...\n" unless $response =~ /^\{/;
+
+	my $json_pkg;
+	eval {
+		require JSON::XS;
+		$json_pkg = "JSON::XS";
+		1;
+	} or do {
+		require JSON::PP;
+		$json_pkg = "JSON::PP";
+	};
+
+	my $o = $json_pkg->new->utf8->decode($response);
+
+	if ($retry > 0 and $o->{error} and $o->{error} =~ m/unable to resolve root .* directory (.*) is not watched/) {
+		print STDERR "Adding '$git_work_tree' to watchman's watch list.\n";
+		$retry--;
+		qx/watchman watch "$git_work_tree"/;
+		die "Failed to make watchman watch '$git_work_tree'.\n" .
+		    "Falling back to scanning...\n" if $? != 0;
+
+		# Watchman will always return all files on the first query so
+		# return the fast "everything is dirty" flag to git and do the
+		# Watchman query just to get it over with now so we won't pay
+		# the cost in git to look up each individual file.
+		print "/\0";
+		eval { launch_watchman() };
+		exit 0;
+	}
+
+	die "Watchman: $o->{error}.\n" .
+	    "Falling back to scanning...\n" if $o->{error};
+
+	binmode STDOUT, ":utf8";
+	local $, = "\0";
+	print @{$o->{files}};
+}
diff --git a/modules/git/tests/repos/repo2_empty/hooks/post-update.sample b/modules/git/tests/repos/repo2_empty/hooks/post-update.sample
new file mode 100755
index 000000000..ec17ec193
--- /dev/null
+++ b/modules/git/tests/repos/repo2_empty/hooks/post-update.sample
@@ -0,0 +1,8 @@
+#!/bin/sh
+#
+# An example hook script to prepare a packed repository for use over
+# dumb transports.
+#
+# To enable this hook, rename this file to "post-update".
+
+exec git update-server-info
diff --git a/modules/git/tests/repos/repo2_empty/hooks/pre-applypatch.sample b/modules/git/tests/repos/repo2_empty/hooks/pre-applypatch.sample
new file mode 100755
index 000000000..4142082bc
--- /dev/null
+++ b/modules/git/tests/repos/repo2_empty/hooks/pre-applypatch.sample
@@ -0,0 +1,14 @@
+#!/bin/sh
+#
+# An example hook script to verify what is about to be committed
+# by applypatch from an e-mail message.
+#
+# The hook should exit with non-zero status after issuing an
+# appropriate message if it wants to stop the commit.
+#
+# To enable this hook, rename this file to "pre-applypatch".
+
+. git-sh-setup
+precommit="$(git rev-parse --git-path hooks/pre-commit)"
+test -x "$precommit" && exec "$precommit" ${1+"$@"}
+:
diff --git a/modules/git/tests/repos/repo2_empty/hooks/pre-commit.sample b/modules/git/tests/repos/repo2_empty/hooks/pre-commit.sample
new file mode 100755
index 000000000..6a7564163
--- /dev/null
+++ b/modules/git/tests/repos/repo2_empty/hooks/pre-commit.sample
@@ -0,0 +1,49 @@
+#!/bin/sh
+#
+# An example hook script to verify what is about to be committed.
+# Called by "git commit" with no arguments.  The hook should
+# exit with non-zero status after issuing an appropriate message if
+# it wants to stop the commit.
+#
+# To enable this hook, rename this file to "pre-commit".
+
+if git rev-parse --verify HEAD >/dev/null 2>&1
+then
+	against=HEAD
+else
+	# Initial commit: diff against an empty tree object
+	against=$(git hash-object -t tree /dev/null)
+fi
+
+# If you want to allow non-ASCII filenames set this variable to true.
+allownonascii=$(git config --bool hooks.allownonascii)
+
+# Redirect output to stderr.
+exec 1>&2
+
+# Cross platform projects tend to avoid non-ASCII filenames; prevent
+# them from being added to the repository. We exploit the fact that the
+# printable range starts at the space character and ends with tilde.
+if [ "$allownonascii" != "true" ] &&
+	# Note that the use of brackets around a tr range is ok here, (it's
+	# even required, for portability to Solaris 10's /usr/bin/tr), since
+	# the square bracket bytes happen to fall in the designated range.
+	test $(git diff --cached --name-only --diff-filter=A -z $against |
+	  LC_ALL=C tr -d '[ -~]\0' | wc -c) != 0
+then
+	cat <<\EOF
+Error: Attempt to add a non-ASCII file name.
+
+This can cause problems if you want to work with people on other platforms.
+
+To be portable it is advisable to rename the file.
+
+If you know what you are doing you can disable this check using:
+
+  git config hooks.allownonascii true
+EOF
+	exit 1
+fi
+
+# If there are whitespace errors, print the offending file names and fail.
+exec git diff-index --check --cached $against --
diff --git a/modules/git/tests/repos/repo2_empty/hooks/pre-push.sample b/modules/git/tests/repos/repo2_empty/hooks/pre-push.sample
new file mode 100755
index 000000000..6187dbf43
--- /dev/null
+++ b/modules/git/tests/repos/repo2_empty/hooks/pre-push.sample
@@ -0,0 +1,53 @@
+#!/bin/sh
+
+# An example hook script to verify what is about to be pushed.  Called by "git
+# push" after it has checked the remote status, but before anything has been
+# pushed.  If this script exits with a non-zero status nothing will be pushed.
+#
+# This hook is called with the following parameters:
+#
+# $1 -- Name of the remote to which the push is being done
+# $2 -- URL to which the push is being done
+#
+# If pushing without using a named remote those arguments will be equal.
+#
+# Information about the commits which are being pushed is supplied as lines to
+# the standard input in the form:
+#
+#   <local ref> <local sha1> <remote ref> <remote sha1>
+#
+# This sample shows how to prevent push of commits where the log message starts
+# with "WIP" (work in progress).
+
+remote="$1"
+url="$2"
+
+z40=0000000000000000000000000000000000000000
+
+while read local_ref local_sha remote_ref remote_sha
+do
+	if [ "$local_sha" = $z40 ]
+	then
+		# Handle delete
+		:
+	else
+		if [ "$remote_sha" = $z40 ]
+		then
+			# New branch, examine all commits
+			range="$local_sha"
+		else
+			# Update to existing branch, examine new commits
+			range="$remote_sha..$local_sha"
+		fi
+
+		# Check for WIP commit
+		commit=`git rev-list -n 1 --grep '^WIP' "$range"`
+		if [ -n "$commit" ]
+		then
+			echo >&2 "Found WIP commit in $local_ref, not pushing"
+			exit 1
+		fi
+	fi
+done
+
+exit 0
diff --git a/modules/git/tests/repos/repo2_empty/hooks/pre-rebase.sample b/modules/git/tests/repos/repo2_empty/hooks/pre-rebase.sample
new file mode 100755
index 000000000..6cbef5c37
--- /dev/null
+++ b/modules/git/tests/repos/repo2_empty/hooks/pre-rebase.sample
@@ -0,0 +1,169 @@
+#!/bin/sh
+#
+# Copyright (c) 2006, 2008 Junio C Hamano
+#
+# The "pre-rebase" hook is run just before "git rebase" starts doing
+# its job, and can prevent the command from running by exiting with
+# non-zero status.
+#
+# The hook is called with the following parameters:
+#
+# $1 -- the upstream the series was forked from.
+# $2 -- the branch being rebased (or empty when rebasing the current branch).
+#
+# This sample shows how to prevent topic branches that are already
+# merged to 'next' branch from getting rebased, because allowing it
+# would result in rebasing already published history.
+
+publish=next
+basebranch="$1"
+if test "$#" = 2
+then
+	topic="refs/heads/$2"
+else
+	topic=`git symbolic-ref HEAD` ||
+	exit 0 ;# we do not interrupt rebasing detached HEAD
+fi
+
+case "$topic" in
+refs/heads/??/*)
+	;;
+*)
+	exit 0 ;# we do not interrupt others.
+	;;
+esac
+
+# Now we are dealing with a topic branch being rebased
+# on top of master.  Is it OK to rebase it?
+
+# Does the topic really exist?
+git show-ref -q "$topic" || {
+	echo >&2 "No such branch $topic"
+	exit 1
+}
+
+# Is topic fully merged to master?
+not_in_master=`git rev-list --pretty=oneline ^master "$topic"`
+if test -z "$not_in_master"
+then
+	echo >&2 "$topic is fully merged to master; better remove it."
+	exit 1 ;# we could allow it, but there is no point.
+fi
+
+# Is topic ever merged to next?  If so you should not be rebasing it.
+only_next_1=`git rev-list ^master "^$topic" ${publish} | sort`
+only_next_2=`git rev-list ^master           ${publish} | sort`
+if test "$only_next_1" = "$only_next_2"
+then
+	not_in_topic=`git rev-list "^$topic" master`
+	if test -z "$not_in_topic"
+	then
+		echo >&2 "$topic is already up to date with master"
+		exit 1 ;# we could allow it, but there is no point.
+	else
+		exit 0
+	fi
+else
+	not_in_next=`git rev-list --pretty=oneline ^${publish} "$topic"`
+	/usr/bin/perl -e '
+		my $topic = $ARGV[0];
+		my $msg = "* $topic has commits already merged to public branch:\n";
+		my (%not_in_next) = map {
+			/^([0-9a-f]+) /;
+			($1 => 1);
+		} split(/\n/, $ARGV[1]);
+		for my $elem (map {
+				/^([0-9a-f]+) (.*)$/;
+				[$1 => $2];
+			} split(/\n/, $ARGV[2])) {
+			if (!exists $not_in_next{$elem->[0]}) {
+				if ($msg) {
+					print STDERR $msg;
+					undef $msg;
+				}
+				print STDERR " $elem->[1]\n";
+			}
+		}
+	' "$topic" "$not_in_next" "$not_in_master"
+	exit 1
+fi
+
+<<\DOC_END
+
+This sample hook safeguards topic branches that have been
+published from being rewound.
+
+The workflow assumed here is:
+
+ * Once a topic branch forks from "master", "master" is never
+   merged into it again (either directly or indirectly).
+
+ * Once a topic branch is fully cooked and merged into "master",
+   it is deleted.  If you need to build on top of it to correct
+   earlier mistakes, a new topic branch is created by forking at
+   the tip of the "master".  This is not strictly necessary, but
+   it makes it easier to keep your history simple.
+
+ * Whenever you need to test or publish your changes to topic
+   branches, merge them into "next" branch.
+
+The script, being an example, hardcodes the publish branch name
+to be "next", but it is trivial to make it configurable via
+$GIT_DIR/config mechanism.
+
+With this workflow, you would want to know:
+
+(1) ... if a topic branch has ever been merged to "next".  Young
+    topic branches can have stupid mistakes you would rather
+    clean up before publishing, and things that have not been
+    merged into other branches can be easily rebased without
+    affecting other people.  But once it is published, you would
+    not want to rewind it.
+
+(2) ... if a topic branch has been fully merged to "master".
+    Then you can delete it.  More importantly, you should not
+    build on top of it -- other people may already want to
+    change things related to the topic as patches against your
+    "master", so if you need further changes, it is better to
+    fork the topic (perhaps with the same name) afresh from the
+    tip of "master".
+
+Let's look at this example:
+
+		   o---o---o---o---o---o---o---o---o---o "next"
+		  /       /           /           /
+		 /   a---a---b A     /           /
+		/   /               /           /
+	       /   /   c---c---c---c B         /
+	      /   /   /             \         /
+	     /   /   /   b---b C     \       /
+	    /   /   /   /             \     /
+    ---o---o---o---o---o---o---o---o---o---o---o "master"
+
+
+A, B and C are topic branches.
+
+ * A has one fix since it was merged up to "next".
+
+ * B has finished.  It has been fully merged up to "master" and "next",
+   and is ready to be deleted.
+
+ * C has not merged to "next" at all.
+
+We would want to allow C to be rebased, refuse A, and encourage
+B to be deleted.
+
+To compute (1):
+
+	git rev-list ^master ^topic next
+	git rev-list ^master        next
+
+	if these match, topic has not merged in next at all.
+
+To compute (2):
+
+	git rev-list master..topic
+
+	if this is empty, it is fully merged to "master".
+
+DOC_END
diff --git a/modules/git/tests/repos/repo2_empty/hooks/pre-receive.sample b/modules/git/tests/repos/repo2_empty/hooks/pre-receive.sample
new file mode 100755
index 000000000..a1fd29ec1
--- /dev/null
+++ b/modules/git/tests/repos/repo2_empty/hooks/pre-receive.sample
@@ -0,0 +1,24 @@
+#!/bin/sh
+#
+# An example hook script to make use of push options.
+# The example simply echoes all push options that start with 'echoback='
+# and rejects all pushes when the "reject" push option is used.
+#
+# To enable this hook, rename this file to "pre-receive".
+
+if test -n "$GIT_PUSH_OPTION_COUNT"
+then
+	i=0
+	while test "$i" -lt "$GIT_PUSH_OPTION_COUNT"
+	do
+		eval "value=\$GIT_PUSH_OPTION_$i"
+		case "$value" in
+		echoback=*)
+			echo "echo from the pre-receive-hook: ${value#*=}" >&2
+			;;
+		reject)
+			exit 1
+		esac
+		i=$((i + 1))
+	done
+fi
diff --git a/modules/git/tests/repos/repo2_empty/hooks/prepare-commit-msg.sample b/modules/git/tests/repos/repo2_empty/hooks/prepare-commit-msg.sample
new file mode 100755
index 000000000..10fa14c5a
--- /dev/null
+++ b/modules/git/tests/repos/repo2_empty/hooks/prepare-commit-msg.sample
@@ -0,0 +1,42 @@
+#!/bin/sh
+#
+# An example hook script to prepare the commit log message.
+# Called by "git commit" with the name of the file that has the
+# commit message, followed by the description of the commit
+# message's source.  The hook's purpose is to edit the commit
+# message file.  If the hook fails with a non-zero status,
+# the commit is aborted.
+#
+# To enable this hook, rename this file to "prepare-commit-msg".
+
+# This hook includes three examples. The first one removes the
+# "# Please enter the commit message..." help message.
+#
+# The second includes the output of "git diff --name-status -r"
+# into the message, just before the "git status" output.  It is
+# commented because it doesn't cope with --amend or with squashed
+# commits.
+#
+# The third example adds a Signed-off-by line to the message, that can
+# still be edited.  This is rarely a good idea.
+
+COMMIT_MSG_FILE=$1
+COMMIT_SOURCE=$2
+SHA1=$3
+
+/usr/bin/perl -i.bak -ne 'print unless(m/^. Please enter the commit message/..m/^#$/)' "$COMMIT_MSG_FILE"
+
+# case "$COMMIT_SOURCE,$SHA1" in
+#  ,|template,)
+#    /usr/bin/perl -i.bak -pe '
+#       print "\n" . `git diff --cached --name-status -r`
+# 	 if /^#/ && $first++ == 0' "$COMMIT_MSG_FILE" ;;
+#  *) ;;
+# esac
+
+# SOB=$(git var GIT_COMMITTER_IDENT | sed -n 's/^\(.*>\).*$/Signed-off-by: \1/p')
+# git interpret-trailers --in-place --trailer "$SOB" "$COMMIT_MSG_FILE"
+# if test -z "$COMMIT_SOURCE"
+# then
+#   /usr/bin/perl -i.bak -pe 'print "\n" if !$first_line++' "$COMMIT_MSG_FILE"
+# fi
diff --git a/modules/git/tests/repos/repo2_empty/hooks/update.sample b/modules/git/tests/repos/repo2_empty/hooks/update.sample
new file mode 100755
index 000000000..80ba94135
--- /dev/null
+++ b/modules/git/tests/repos/repo2_empty/hooks/update.sample
@@ -0,0 +1,128 @@
+#!/bin/sh
+#
+# An example hook script to block unannotated tags from entering.
+# Called by "git receive-pack" with arguments: refname sha1-old sha1-new
+#
+# To enable this hook, rename this file to "update".
+#
+# Config
+# ------
+# hooks.allowunannotated
+#   This boolean sets whether unannotated tags will be allowed into the
+#   repository.  By default they won't be.
+# hooks.allowdeletetag
+#   This boolean sets whether deleting tags will be allowed in the
+#   repository.  By default they won't be.
+# hooks.allowmodifytag
+#   This boolean sets whether a tag may be modified after creation. By default
+#   it won't be.
+# hooks.allowdeletebranch
+#   This boolean sets whether deleting branches will be allowed in the
+#   repository.  By default they won't be.
+# hooks.denycreatebranch
+#   This boolean sets whether remotely creating branches will be denied
+#   in the repository.  By default this is allowed.
+#
+
+# --- Command line
+refname="$1"
+oldrev="$2"
+newrev="$3"
+
+# --- Safety check
+if [ -z "$GIT_DIR" ]; then
+	echo "Don't run this script from the command line." >&2
+	echo " (if you want, you could supply GIT_DIR then run" >&2
+	echo "  $0 <ref> <oldrev> <newrev>)" >&2
+	exit 1
+fi
+
+if [ -z "$refname" -o -z "$oldrev" -o -z "$newrev" ]; then
+	echo "usage: $0 <ref> <oldrev> <newrev>" >&2
+	exit 1
+fi
+
+# --- Config
+allowunannotated=$(git config --bool hooks.allowunannotated)
+allowdeletebranch=$(git config --bool hooks.allowdeletebranch)
+denycreatebranch=$(git config --bool hooks.denycreatebranch)
+allowdeletetag=$(git config --bool hooks.allowdeletetag)
+allowmodifytag=$(git config --bool hooks.allowmodifytag)
+
+# check for no description
+projectdesc=$(sed -e '1q' "$GIT_DIR/description")
+case "$projectdesc" in
+"Unnamed repository"* | "")
+	echo "*** Project description file hasn't been set" >&2
+	exit 1
+	;;
+esac
+
+# --- Check types
+# if $newrev is 0000...0000, it's a commit to delete a ref.
+zero="0000000000000000000000000000000000000000"
+if [ "$newrev" = "$zero" ]; then
+	newrev_type=delete
+else
+	newrev_type=$(git cat-file -t $newrev)
+fi
+
+case "$refname","$newrev_type" in
+	refs/tags/*,commit)
+		# un-annotated tag
+		short_refname=${refname##refs/tags/}
+		if [ "$allowunannotated" != "true" ]; then
+			echo "*** The un-annotated tag, $short_refname, is not allowed in this repository" >&2
+			echo "*** Use 'git tag [ -a | -s ]' for tags you want to propagate." >&2
+			exit 1
+		fi
+		;;
+	refs/tags/*,delete)
+		# delete tag
+		if [ "$allowdeletetag" != "true" ]; then
+			echo "*** Deleting a tag is not allowed in this repository" >&2
+			exit 1
+		fi
+		;;
+	refs/tags/*,tag)
+		# annotated tag
+		if [ "$allowmodifytag" != "true" ] && git rev-parse $refname > /dev/null 2>&1
+		then
+			echo "*** Tag '$refname' already exists." >&2
+			echo "*** Modifying a tag is not allowed in this repository." >&2
+			exit 1
+		fi
+		;;
+	refs/heads/*,commit)
+		# branch
+		if [ "$oldrev" = "$zero" -a "$denycreatebranch" = "true" ]; then
+			echo "*** Creating a branch is not allowed in this repository" >&2
+			exit 1
+		fi
+		;;
+	refs/heads/*,delete)
+		# delete branch
+		if [ "$allowdeletebranch" != "true" ]; then
+			echo "*** Deleting a branch is not allowed in this repository" >&2
+			exit 1
+		fi
+		;;
+	refs/remotes/*,commit)
+		# tracking branch
+		;;
+	refs/remotes/*,delete)
+		# delete tracking branch
+		if [ "$allowdeletebranch" != "true" ]; then
+			echo "*** Deleting a tracking branch is not allowed in this repository" >&2
+			exit 1
+		fi
+		;;
+	*)
+		# Anything else (is there anything else?)
+		echo "*** Update hook: unknown type of update to ref $refname of type $newrev_type" >&2
+		exit 1
+		;;
+esac
+
+# --- Finished
+exit 0
diff --git a/modules/git/tests/repos/repo2_empty/info/exclude b/modules/git/tests/repos/repo2_empty/info/exclude
new file mode 100644
index 000000000..a5196d1be
--- /dev/null
+++ b/modules/git/tests/repos/repo2_empty/info/exclude
@@ -0,0 +1,6 @@
+# git ls-files --others --exclude-from=.git/info/exclude
+# Lines that start with '#' are comments.
+# For a project mostly in C, the following would be a good set of
+# exclude patterns (uncomment them if you want to use them):
+# *.[oa]
+# *~
diff --git a/modules/git/tests/repos/repo2_empty/objects/info/.gitkeep b/modules/git/tests/repos/repo2_empty/objects/info/.gitkeep
new file mode 100644
index 000000000..e69de29bb
diff --git a/modules/git/tests/repos/repo2_empty/objects/pack/.gitkeep b/modules/git/tests/repos/repo2_empty/objects/pack/.gitkeep
new file mode 100644
index 000000000..e69de29bb
diff --git a/modules/git/tests/repos/repo2_empty/refs/heads/.gitkeep b/modules/git/tests/repos/repo2_empty/refs/heads/.gitkeep
new file mode 100644
index 000000000..e69de29bb
diff --git a/modules/git/tests/repos/repo2_empty/refs/tags/.gitkeep b/modules/git/tests/repos/repo2_empty/refs/tags/.gitkeep
new file mode 100644
index 000000000..e69de29bb
diff --git a/modules/repofiles/temp_repo.go b/modules/repofiles/temp_repo.go
index ec3562867..ef75709c2 100644
--- a/modules/repofiles/temp_repo.go
+++ b/modules/repofiles/temp_repo.go
@@ -50,7 +50,7 @@ func (t *TemporaryUploadRepository) Close() {
 func (t *TemporaryUploadRepository) Clone(branch string) error {
 	if _, stderr, err := process.GetManager().ExecTimeout(5*time.Minute,
 		fmt.Sprintf("Clone (git clone -s --bare): %s", t.basePath),
-		"git", "clone", "-s", "--bare", "-b", branch, t.repo.RepoPath(), t.basePath); err != nil {
+		git.GitExecutable, "clone", "-s", "--bare", "-b", branch, t.repo.RepoPath(), t.basePath); err != nil {
 		if matched, _ := regexp.MatchString(".*Remote branch .* not found in upstream origin.*", stderr); matched {
 			return git.ErrBranchNotExist{
 				Name: branch,
@@ -79,7 +79,7 @@ func (t *TemporaryUploadRepository) SetDefaultIndex() error {
 	if _, stderr, err := process.GetManager().ExecDir(5*time.Minute,
 		t.basePath,
 		fmt.Sprintf("SetDefaultIndex (git read-tree HEAD): %s", t.basePath),
-		"git", "read-tree", "HEAD"); err != nil {
+		git.GitExecutable, "read-tree", "HEAD"); err != nil {
 		return fmt.Errorf("SetDefaultIndex: %v %s", err, stderr)
 	}
 	return nil
@@ -101,7 +101,7 @@ func (t *TemporaryUploadRepository) LsFiles(filenames ...string) ([]string, erro
 		}
 	}
 
-	cmd := exec.CommandContext(ctx, "git", cmdArgs...)
+	cmd := exec.CommandContext(ctx, git.GitExecutable, cmdArgs...)
 	desc := fmt.Sprintf("lsFiles: (git ls-files) %v", cmdArgs)
 	cmd.Dir = t.basePath
 	cmd.Stdout = stdOut
@@ -146,7 +146,7 @@ func (t *TemporaryUploadRepository) RemoveFilesFromIndex(filenames ...string) er
 	defer cancel()
 
 	cmdArgs := []string{"update-index", "--remove", "-z", "--index-info"}
-	cmd := exec.CommandContext(ctx, "git", cmdArgs...)
+	cmd := exec.CommandContext(ctx, git.GitExecutable, cmdArgs...)
 	desc := fmt.Sprintf("removeFilesFromIndex: (git update-index) %v", filenames)
 	cmd.Dir = t.basePath
 	cmd.Stdout = stdOut
@@ -174,7 +174,7 @@ func (t *TemporaryUploadRepository) HashObject(content io.Reader) (string, error
 	ctx, cancel := context.WithTimeout(context.Background(), timeout)
 	defer cancel()
 
-	hashCmd := exec.CommandContext(ctx, "git", "hash-object", "-w", "--stdin")
+	hashCmd := exec.CommandContext(ctx, git.GitExecutable, "hash-object", "-w", "--stdin")
 	hashCmd.Dir = t.basePath
 	hashCmd.Stdin = content
 	stdOutBuffer := new(bytes.Buffer)
@@ -203,7 +203,7 @@ func (t *TemporaryUploadRepository) AddObjectToIndex(mode, objectHash, objectPat
 	if _, stderr, err := process.GetManager().ExecDir(5*time.Minute,
 		t.basePath,
 		fmt.Sprintf("addObjectToIndex (git update-index): %s", t.basePath),
-		"git", "update-index", "--add", "--replace", "--cacheinfo", mode, objectHash, objectPath); err != nil {
+		git.GitExecutable, "update-index", "--add", "--replace", "--cacheinfo", mode, objectHash, objectPath); err != nil {
 		if matched, _ := regexp.MatchString(".*Invalid path '.*", stderr); matched {
 			return models.ErrFilePathInvalid{
 				Message: objectPath,
@@ -220,7 +220,7 @@ func (t *TemporaryUploadRepository) WriteTree() (string, error) {
 	treeHash, stderr, err := process.GetManager().ExecDir(5*time.Minute,
 		t.basePath,
 		fmt.Sprintf("WriteTree (git write-tree): %s", t.basePath),
-		"git", "write-tree")
+		git.GitExecutable, "write-tree")
 	if err != nil {
 		return "", fmt.Errorf("git write-tree: %s", stderr)
 	}
@@ -240,7 +240,7 @@ func (t *TemporaryUploadRepository) GetLastCommitByRef(ref string) (string, erro
 	treeHash, stderr, err := process.GetManager().ExecDir(5*time.Minute,
 		t.basePath,
 		fmt.Sprintf("GetLastCommit (git rev-parse %s): %s", ref, t.basePath),
-		"git", "rev-parse", ref)
+		git.GitExecutable, "rev-parse", ref)
 	if err != nil {
 		return "", fmt.Errorf("git rev-parse %s: %s", ref, stderr)
 	}
@@ -267,7 +267,7 @@ func (t *TemporaryUploadRepository) CommitTree(author, committer *models.User, t
 		t.basePath,
 		fmt.Sprintf("commitTree (git commit-tree): %s", t.basePath),
 		env,
-		"git", "commit-tree", treeHash, "-p", "HEAD", "-m", message)
+		git.GitExecutable, "commit-tree", treeHash, "-p", "HEAD", "-m", message)
 	if err != nil {
 		return "", fmt.Errorf("git commit-tree: %s", stderr)
 	}
@@ -283,7 +283,7 @@ func (t *TemporaryUploadRepository) Push(doer *models.User, commitHash string, b
 		t.basePath,
 		fmt.Sprintf("actuallyPush (git push): %s", t.basePath),
 		env,
-		"git", "push", t.repo.RepoPath(), strings.TrimSpace(commitHash)+":refs/heads/"+strings.TrimSpace(branch)); err != nil {
+		git.GitExecutable, "push", t.repo.RepoPath(), strings.TrimSpace(commitHash)+":refs/heads/"+strings.TrimSpace(branch)); err != nil {
 		return fmt.Errorf("git push: %s", stderr)
 	}
 	return nil
@@ -297,7 +297,7 @@ func (t *TemporaryUploadRepository) DiffIndex() (diff *models.Diff, err error) {
 
 	stdErr := new(bytes.Buffer)
 
-	cmd := exec.CommandContext(ctx, "git", "diff-index", "--cached", "-p", "HEAD")
+	cmd := exec.CommandContext(ctx, git.GitExecutable, "diff-index", "--cached", "-p", "HEAD")
 	cmd.Dir = t.basePath
 	cmd.Stderr = stdErr
 
@@ -341,7 +341,7 @@ func (t *TemporaryUploadRepository) CheckAttribute(attribute string, args ...str
 		}
 	}
 
-	cmd := exec.CommandContext(ctx, "git", cmdArgs...)
+	cmd := exec.CommandContext(ctx, git.GitExecutable, cmdArgs...)
 	desc := fmt.Sprintf("checkAttr: (git check-attr) %s %v", attribute, cmdArgs)
 	cmd.Dir = t.basePath
 	cmd.Stdout = stdOut
diff --git a/routers/repo/blame.go b/routers/repo/blame.go
index 2b2f45f0b..07952a4ca 100644
--- a/routers/repo/blame.go
+++ b/routers/repo/blame.go
@@ -131,14 +131,14 @@ func RefBlame(ctx *context.Context) {
 	ctx.Data["FileSize"] = blob.Size()
 	ctx.Data["FileName"] = blob.Name()
 
-	blameReader, err := models.CreateBlameReader(models.RepoPath(userName, repoName), commitID, fileName)
+	blameReader, err := git.CreateBlameReader(models.RepoPath(userName, repoName), commitID, fileName)
 	if err != nil {
 		ctx.NotFound("CreateBlameReader", err)
 		return
 	}
 	defer blameReader.Close()
 
-	blameParts := make([]models.BlamePart, 0)
+	blameParts := make([]git.BlamePart, 0)
 
 	for {
 		blamePart, err := blameReader.NextPart()
@@ -189,7 +189,7 @@ func RefBlame(ctx *context.Context) {
 	ctx.HTML(200, tplBlame)
 }
 
-func renderBlame(ctx *context.Context, blameParts []models.BlamePart, commitNames map[string]models.UserCommit) {
+func renderBlame(ctx *context.Context, blameParts []git.BlamePart, commitNames map[string]models.UserCommit) {
 	repoLink := ctx.Repo.RepoLink
 
 	var lines = make([]string, 0)
diff --git a/routers/repo/http.go b/routers/repo/http.go
index 307220944..48f562505 100644
--- a/routers/repo/http.go
+++ b/routers/repo/http.go
@@ -22,6 +22,7 @@ import (
 	"code.gitea.io/gitea/modules/auth"
 	"code.gitea.io/gitea/modules/base"
 	"code.gitea.io/gitea/modules/context"
+	"code.gitea.io/gitea/modules/git"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/modules/util"
@@ -343,19 +344,11 @@ var routes = []route{
 	{regexp.MustCompile(`(.*?)/objects/pack/pack-[0-9a-f]{40}\.idx$`), "GET", getIdxFile},
 }
 
-// FIXME: use process module
-func gitCommand(dir string, args ...string) []byte {
-	cmd := exec.Command("git", args...)
-	cmd.Dir = dir
-	out, err := cmd.Output()
+func getGitConfig(option, dir string) string {
+	out, err := git.NewCommand("config", option).RunInDir(dir)
 	if err != nil {
 		log.Error("%v - %s", err, out)
 	}
-	return out
-}
-
-func getGitConfig(option, dir string) string {
-	out := string(gitCommand(dir, "config", option))
 	return out[0 : len(out)-1]
 }
 
@@ -422,7 +415,7 @@ func serviceRPC(h serviceHandler, service string) {
 	h.environ = append(h.environ, "SSH_ORIGINAL_COMMAND="+service)
 
 	var stderr bytes.Buffer
-	cmd := exec.Command("git", service, "--stateless-rpc", h.dir)
+	cmd := exec.Command(git.GitExecutable, service, "--stateless-rpc", h.dir)
 	cmd.Dir = h.dir
 	if service == "receive-pack" {
 		cmd.Env = append(os.Environ(), h.environ...)
@@ -453,7 +446,11 @@ func getServiceType(r *http.Request) string {
 }
 
 func updateServerInfo(dir string) []byte {
-	return gitCommand(dir, "update-server-info")
+	out, err := git.NewCommand("update-server-info").RunInDirBytes(dir)
+	if err != nil {
+		log.Error(fmt.Sprintf("%v - %s", err, string(out)))
+	}
+	return out
 }
 
 func packetWrite(str string) []byte {
@@ -468,7 +465,10 @@ func getInfoRefs(h serviceHandler) {
 	h.setHeaderNoCache()
 	if hasAccess(getServiceType(h.r), h, false) {
 		service := getServiceType(h.r)
-		refs := gitCommand(h.dir, service, "--stateless-rpc", "--advertise-refs", ".")
+		refs, err := git.NewCommand(service, "--stateless-rpc", "--advertise-refs", ".").RunInDirBytes(h.dir)
+		if err != nil {
+			log.Error(fmt.Sprintf("%v - %s", err, string(refs)))
+		}
 
 		h.w.Header().Set("Content-Type", fmt.Sprintf("application/x-git-%s-advertisement", service))
 		h.w.WriteHeader(http.StatusOK)