Use git.HOME_PATH for Git HOME directory (#20114)

* Add git.HOME_PATH

* add legacy file check

* Apply suggestions from code review

Co-authored-by: zeripath <art27@cantab.net>

* pass env GNUPGHOME to git command, move the existing .gitconfig to new home, make the fix for 1.17rc more clear.

* set git.HOME_PATH for docker images to default HOME

* Revert "set git.HOME_PATH for docker images to default HOME"

This reverts commit f120101ddc267cef74e4f4b92c783d5fc8e275a1.

* force Gitea to use a stable GNUPGHOME directory

* extra check to ensure only process dir or symlink for legacy files

* refactor variable name

* The legacy dir check (for 1.17-rc1) could be removed with 1.18 release, since users should have upgraded from 1.17-rc to 1.17-stable

* Update modules/git/git.go

Co-authored-by: Steven Kriegler <61625851+justusbunsi@users.noreply.github.com>

* remove initFixGitHome117rc

* Update git.go

* Update docs/content/doc/advanced/config-cheat-sheet.en-us.md

Co-authored-by: zeripath <art27@cantab.net>
Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: Steven Kriegler <61625851+justusbunsi@users.noreply.github.com>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

4 files changed, 51 insertions, 23 deletions

diff --git a/modules/git/command.go b/modules/git/command.go
index d71497f1d7..a1bacbb707 100644
--- a/modules/git/command.go
+++ b/modules/git/command.go
@@ -105,23 +105,36 @@ type RunOpts struct {
 	PipelineFunc   func(context.Context, context.CancelFunc) error
 }
 
-// CommonGitCmdEnvs returns the common environment variables for a "git" command.
-func CommonGitCmdEnvs() []string {
+func commonBaseEnvs() []string {
 	// at the moment, do not set "GIT_CONFIG_NOSYSTEM", users may have put some configs like "receive.certNonceSeed" in it
-	return []string{
-		fmt.Sprintf("LC_ALL=%s", DefaultLocale),
-		"GIT_TERMINAL_PROMPT=0",    // avoid prompting for credentials interactively, supported since git v2.3
-		"GIT_NO_REPLACE_OBJECTS=1", // ignore replace references (https://git-scm.com/docs/git-replace)
+	envs := []string{
 		"HOME=" + HomeDir(),        // make Gitea use internal git config only, to prevent conflicts with user's git config
+		"GIT_NO_REPLACE_OBJECTS=1", // ignore replace references (https://git-scm.com/docs/git-replace)
+	}
+
+	// some environment variables should be passed to git command
+	passThroughEnvKeys := []string{
+		"GNUPGHOME", // git may call gnupg to do commit signing
+	}
+	for _, key := range passThroughEnvKeys {
+		if val, ok := os.LookupEnv(key); ok {
+			envs = append(envs, key+"="+val)
+		}
 	}
+	return envs
+}
+
+// CommonGitCmdEnvs returns the common environment variables for a "git" command.
+func CommonGitCmdEnvs() []string {
+	return append(commonBaseEnvs(), []string{
+		"LC_ALL=" + DefaultLocale,
+		"GIT_TERMINAL_PROMPT=0", // avoid prompting for credentials interactively, supported since git v2.3
+	}...)
 }
 
 // CommonCmdServEnvs is like CommonGitCmdEnvs but it only returns minimal required environment variables for the "gitea serv" command
 func CommonCmdServEnvs() []string {
-	return []string{
-		"GIT_NO_REPLACE_OBJECTS=1", // ignore replace references (https://git-scm.com/docs/git-replace)
-		"HOME=" + HomeDir(),        // make Gitea use internal git config only, to prevent conflicts with user's git config
-	}
+	return commonBaseEnvs()
 }
 
 // Run runs the command with the RunOpts
diff --git a/modules/git/git.go b/modules/git/git.go
index 0652a75f9a..3bc08ff93b 100644
--- a/modules/git/git.go
+++ b/modules/git/git.go
@@ -11,6 +11,7 @@ import (
 	"fmt"
 	"os"
 	"os/exec"
+	"path/filepath"
 	"regexp"
 	"runtime"
 	"strings"
@@ -19,7 +20,6 @@ import (
 
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
-
 	"github.com/hashicorp/go-version"
 )
 
@@ -126,8 +126,8 @@ func VersionInfo() string {
 }
 
 func checkInit() error {
-	if setting.RepoRootPath == "" {
-		return errors.New("can not init Git's HomeDir (RepoRootPath is empty), the setting and git modules are not initialized correctly")
+	if setting.Git.HomePath == "" {
+		return errors.New("unable to init Git's HomeDir, incorrect initialization of the setting and git modules")
 	}
 	if DefaultContext != nil {
 		log.Warn("git module has been initialized already, duplicate init should be fixed")
@@ -137,14 +137,14 @@ func checkInit() error {
 
 // HomeDir is the home dir for git to store the global config file used by Gitea internally
 func HomeDir() string {
-	if setting.RepoRootPath == "" {
+	if setting.Git.HomePath == "" {
 		// strict check, make sure the git module is initialized correctly.
 		// attention: when the git module is called in gitea sub-command (serv/hook), the log module is not able to show messages to users.
 		// for example: if there is gitea git hook code calling git.NewCommand before git.InitXxx, the integration test won't show the real failure reasons.
-		log.Fatal("can not get Git's HomeDir (RepoRootPath is empty), the setting and git modules are not initialized correctly")
+		log.Fatal("Unable to init Git's HomeDir, incorrect initialization of the setting and git modules")
 		return ""
 	}
-	return setting.RepoRootPath
+	return setting.Git.HomePath
 }
 
 // InitSimple initializes git module with a very simple step, no config changes, no global command arguments.
@@ -175,11 +175,15 @@ func InitOnceWithSync(ctx context.Context) (err error) {
 	}
 
 	initOnce.Do(func() {
-		err = InitSimple(ctx)
-		if err != nil {
+		if err = InitSimple(ctx); err != nil {
 			return
 		}
 
+		// when git works with gnupg (commit signing), there should be a stable home for gnupg commands
+		if _, ok := os.LookupEnv("GNUPGHOME"); !ok {
+			_ = os.Setenv("GNUPGHOME", filepath.Join(HomeDir(), ".gnupg"))
+		}
+
 		// Since git wire protocol has been released from git v2.18
 		if setting.Git.EnableAutoGitWireProtocol && CheckGitVersionAtLeast("2.18") == nil {
 			globalCommandArgs = append(globalCommandArgs, "-c", "protocol.version=2")
@@ -206,7 +210,7 @@ func InitOnceWithSync(ctx context.Context) (err error) {
 // syncGitConfig only modifies gitconfig, won't change global variables (otherwise there will be data-race problem)
 func syncGitConfig() (err error) {
 	if err = os.MkdirAll(HomeDir(), os.ModePerm); err != nil {
-		return fmt.Errorf("unable to create directory %s, err: %w", setting.RepoRootPath, err)
+		return fmt.Errorf("unable to prepare git home directory %s, err: %w", HomeDir(), err)
 	}
 
 	// Git requires setting user.name and user.email in order to commit changes - old comment: "if they're not set just add some defaults"
diff --git a/modules/git/git_test.go b/modules/git/git_test.go
index c1a9ec351a..c5a63de064 100644
--- a/modules/git/git_test.go
+++ b/modules/git/git_test.go
@@ -21,12 +21,12 @@ import (
 func testRun(m *testing.M) error {
 	_ = log.NewLogger(1000, "console", "console", `{"level":"trace","stacktracelevel":"NONE","stderr":true}`)
 
-	repoRootPath, err := os.MkdirTemp(os.TempDir(), "repos")
+	gitHomePath, err := os.MkdirTemp(os.TempDir(), "git-home")
 	if err != nil {
 		return fmt.Errorf("unable to create temp dir: %w", err)
 	}
-	defer util.RemoveAll(repoRootPath)
-	setting.RepoRootPath = repoRootPath
+	defer util.RemoveAll(gitHomePath)
+	setting.Git.HomePath = gitHomePath
 
 	if err = InitOnceWithSync(context.Background()); err != nil {
 		return fmt.Errorf("failed to call Init: %w", err)
diff --git a/modules/setting/git.go b/modules/setting/git.go
index 9b2698f01e..266bbc3c5a 100644
--- a/modules/setting/git.go
+++ b/modules/setting/git.go
@@ -5,6 +5,7 @@
 package setting
 
 import (
+	"path/filepath"
 	"time"
 
 	"code.gitea.io/gitea/modules/log"
@@ -13,6 +14,7 @@ import (
 // Git settings
 var Git = struct {
 	Path                      string
+	HomePath                  string
 	DisableDiffHighlight      bool
 	MaxGitDiffLines           int
 	MaxGitDiffLineCharacters  int
@@ -67,7 +69,16 @@ var Git = struct {
 }
 
 func newGit() {
-	if err := Cfg.Section("git").MapTo(&Git); err != nil {
+	sec := Cfg.Section("git")
+
+	if err := sec.MapTo(&Git); err != nil {
 		log.Fatal("Failed to map Git settings: %v", err)
 	}
+
+	Git.HomePath = sec.Key("HOME_PATH").MustString("home")
+	if !filepath.IsAbs(Git.HomePath) {
+		Git.HomePath = filepath.Join(AppDataPath, Git.HomePath)
+	} else {
+		Git.HomePath = filepath.Clean(Git.HomePath)
+	}
 }