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>

8 files changed, 63 insertions, 27 deletions

diff --git a/custom/conf/app.example.ini b/custom/conf/app.example.ini
index 927dc71166..fb43ea95a1 100644
--- a/custom/conf/app.example.ini
+++ b/custom/conf/app.example.ini
@@ -603,7 +603,10 @@ ROUTER = console
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;
 ;; The path of git executable. If empty, Gitea searches through the PATH environment.
-PATH =
+;PATH =
+;;
+;; The HOME directory for Git
+;HOME_PATH = %(APP_DATA_PATH)/home
 ;;
 ;; Disables highlight of added and removed changes
 ;DISABLE_DIFF_HIGHLIGHT = false
diff --git a/docs/content/doc/advanced/config-cheat-sheet.en-us.md b/docs/content/doc/advanced/config-cheat-sheet.en-us.md
index c16a500ef3..84e3c6ae33 100644
--- a/docs/content/doc/advanced/config-cheat-sheet.en-us.md
+++ b/docs/content/doc/advanced/config-cheat-sheet.en-us.md
@@ -948,6 +948,8 @@ Default templates for project boards:
 ## Git (`git`)
 
 - `PATH`: **""**: The path of Git executable. If empty, Gitea searches through the PATH environment.
+- `HOME_PATH`: **%(APP_DATA_PATH)/home**: The HOME directory for Git.
+	  This directory will be used to contain the `.gitconfig` and possible `.gnupg` directories that Gitea's git calls will use. If you can confirm Gitea is the only application running in this environment, you can set it to the normal home directory for Gitea user.
 - `DISABLE_DIFF_HIGHLIGHT`: **false**: Disables highlight of added and removed changes.
 - `MAX_GIT_DIFF_LINES`: **1000**: Max number of lines allowed of a single file in diff view.
 - `MAX_GIT_DIFF_LINE_CHARACTERS`: **5000**: Max character count per line highlighted in diff view.
diff --git a/docs/content/doc/advanced/signing.en-us.md b/docs/content/doc/advanced/signing.en-us.md
index 8ae2f94e9e..9ef94deb75 100644
--- a/docs/content/doc/advanced/signing.en-us.md
+++ b/docs/content/doc/advanced/signing.en-us.md
@@ -97,10 +97,11 @@ repositories, `SIGNING_KEY=default` could be used to provide different
 signing keys on a per-repository basis. However, this is clearly not an
 ideal UI and therefore subject to change.
 
-**Since 1.17**, Gitea runs git in its own home directory `[repository].ROOT` and uses its own config `{[repository].ROOT}/.gitconfig`.
+**Since 1.17**, Gitea runs git in its own home directory `[git].HOME_PATH` (default to `%(APP_DATA_PATH)/home`)
+and uses its own config `{[git].HOME_PATH}/.gitconfig`.
 If you have your own customized git config for Gitea, you should set these configs in system git config (aka `/etc/gitconfig`)
-or the Gitea internal git config `{[repository].ROOT}/.gitconfig`. 
-Related home files for git command (like `.gnupg`) should also be put in Gitea's git home directory `[repository].ROOT`. 
+or the Gitea internal git config `{[git].HOME_PATH}/.gitconfig`. 
+Related home files for git command (like `.gnupg`) should also be put in Gitea's git home directory `[git].HOME_PATH`. 
 
 
 ### `INITIAL_COMMIT`
diff --git a/models/unittest/testdb.go b/models/unittest/testdb.go
index baea46dbce..7f9af55374 100644
--- a/models/unittest/testdb.go
+++ b/models/unittest/testdb.go
@@ -107,6 +107,8 @@ func MainTest(m *testing.M, testOpts *TestOptions) {
 
 	setting.Packages.Storage.Path = filepath.Join(setting.AppDataPath, "packages")
 
+	setting.Git.HomePath = filepath.Join(setting.AppDataPath, "home")
+
 	if err = storage.Init(); err != nil {
 		fatalTestError("storage.Init: %v\n", err)
 	}
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)
+	}
 }