Refactor git module, make Gitea use internal git config (#19732)

* Refactor git module, make Gitea use internal git config, add safe.directory config

* introduce git.InitSimple and git.InitWithConfigSync, make serv cmd use gitconfig

* use HOME instead of GIT_CONFIG_GLOBAL, because git always needs a correct HOME

* fix cmd env in cmd/serv.go

* fine tune error message

* Fix a incorrect test case

* fix configAddNonExist

* fix configAddNonExist logic, add `--fixed-value` flag, add tests

* add configSetNonExist function in case it's needed.

* use configSetNonExist for `user.name` and `user.email`

* add some comments

* Update cmd/serv.go

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

* Update cmd/serv.go

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

* Update modules/git/git.go

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

* Update modules/setting/setting.go

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

* Update modules/git/repo_attribute.go

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

* fix spaces in messages

* use `configSet("core.protectNTFS", ...)` instead of `globalCommandArgs`

* remove GIT_CONFIG_NOSYSTEM, continue to use system's git config

* Update cmd/serv.go

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

* fix merge

* remove code for safe.directory

* separate git.CommonEnvs to CommonGitCmdEnvs and CommonCmdServEnvs

* avoid Golang's data race error

Co-authored-by: zeripath <art27@cantab.net>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

21 files changed, 283 insertions, 190 deletions

diff --git a/cmd/serv.go b/cmd/serv.go
index 6ba3e9de01..6e067a48a5 100644
--- a/cmd/serv.go
+++ b/cmd/serv.go
@@ -6,6 +6,7 @@
 package cmd
 
 import (
+	"context"
 	"fmt"
 	"net/http"
 	"net/url"
@@ -65,6 +66,21 @@ func setup(logPath string, debug bool) {
 	if debug {
 		setting.RunMode = "dev"
 	}
+
+	// Check if setting.RepoRootPath exists. It could be the case that it doesn't exist, this can happen when
+	// `[repository]` `ROOT` is a relative path and $GITEA_WORK_DIR isn't passed to the SSH connection.
+	if _, err := os.Stat(setting.RepoRootPath); err != nil {
+		if os.IsNotExist(err) {
+			_ = fail("Incorrect configuration, no repository directory.", "Directory `[repository].ROOT` %q was not found, please check if $GITEA_WORK_DIR is passed to the SSH connection or make `[repository].ROOT` an absolute value.", setting.RepoRootPath)
+		} else {
+			_ = fail("Incorrect configuration, repository directory is inaccessible", "Directory `[repository].ROOT` %q is inaccessible. err: %v", setting.RepoRootPath, err)
+		}
+		return
+	}
+
+	if err := git.InitSimple(context.Background()); err != nil {
+		_ = fail("Failed to init git", "Failed to init git, err: %v", err)
+	}
 }
 
 var (
@@ -80,12 +96,12 @@ var (
 func fail(userMessage, logMessage string, args ...interface{}) error {
 	// There appears to be a chance to cause a zombie process and failure to read the Exit status
 	// if nothing is outputted on stdout.
-	fmt.Fprintln(os.Stdout, "")
-	fmt.Fprintln(os.Stderr, "Gitea:", userMessage)
+	_, _ = fmt.Fprintln(os.Stdout, "")
+	_, _ = fmt.Fprintln(os.Stderr, "Gitea:", userMessage)
 
 	if len(logMessage) > 0 {
 		if !setting.IsProd {
-			fmt.Fprintf(os.Stderr, logMessage+"\n", args...)
+			_, _ = fmt.Fprintf(os.Stderr, logMessage+"\n", args...)
 		}
 	}
 	ctx, cancel := installSignals()
@@ -237,17 +253,6 @@ func runServ(c *cli.Context) error {
 		}
 		return fail("Internal Server Error", "%s", err.Error())
 	}
-	os.Setenv(repo_module.EnvRepoIsWiki, strconv.FormatBool(results.IsWiki))
-	os.Setenv(repo_module.EnvRepoName, results.RepoName)
-	os.Setenv(repo_module.EnvRepoUsername, results.OwnerName)
-	os.Setenv(repo_module.EnvPusherName, results.UserName)
-	os.Setenv(repo_module.EnvPusherEmail, results.UserEmail)
-	os.Setenv(repo_module.EnvPusherID, strconv.FormatInt(results.UserID, 10))
-	os.Setenv(repo_module.EnvRepoID, strconv.FormatInt(results.RepoID, 10))
-	os.Setenv(repo_module.EnvPRID, fmt.Sprintf("%d", 0))
-	os.Setenv(repo_module.EnvDeployKeyID, fmt.Sprintf("%d", results.DeployKeyID))
-	os.Setenv(repo_module.EnvKeyID, fmt.Sprintf("%d", results.KeyID))
-	os.Setenv(repo_module.EnvAppURL, setting.AppURL)
 
 	// LFS token authentication
 	if verb == lfsAuthenticateVerb {
@@ -298,20 +303,29 @@ func runServ(c *cli.Context) error {
 		gitcmd = exec.CommandContext(ctx, verb, repoPath)
 	}
 
-	// Check if setting.RepoRootPath exists. It could be the case that it doesn't exist, this can happen when
-	// `[repository]` `ROOT` is a relative path and $GITEA_WORK_DIR isn't passed to the SSH connection.
-	if _, err := os.Stat(setting.RepoRootPath); err != nil {
-		if os.IsNotExist(err) {
-			return fail("Incorrect configuration.",
-				"Directory `[repository]` `ROOT` %s was not found, please check if $GITEA_WORK_DIR is passed to the SSH connection or make `[repository]` `ROOT` an absolute value.", setting.RepoRootPath)
-		}
-	}
-
 	process.SetSysProcAttribute(gitcmd)
 	gitcmd.Dir = setting.RepoRootPath
 	gitcmd.Stdout = os.Stdout
 	gitcmd.Stdin = os.Stdin
 	gitcmd.Stderr = os.Stderr
+	gitcmd.Env = append(gitcmd.Env, os.Environ()...)
+	gitcmd.Env = append(gitcmd.Env,
+		repo_module.EnvRepoIsWiki+"="+strconv.FormatBool(results.IsWiki),
+		repo_module.EnvRepoName+"="+results.RepoName,
+		repo_module.EnvRepoUsername+"="+results.OwnerName,
+		repo_module.EnvPusherName+"="+results.UserName,
+		repo_module.EnvPusherEmail+"="+results.UserEmail,
+		repo_module.EnvPusherID+"="+strconv.FormatInt(results.UserID, 10),
+		repo_module.EnvRepoID+"="+strconv.FormatInt(results.RepoID, 10),
+		repo_module.EnvPRID+"="+fmt.Sprintf("%d", 0),
+		repo_module.EnvDeployKeyID+"="+fmt.Sprintf("%d", results.DeployKeyID),
+		repo_module.EnvKeyID+"="+fmt.Sprintf("%d", results.KeyID),
+		repo_module.EnvAppURL+"="+setting.AppURL,
+	)
+	// to avoid breaking, here only use the minimal environment variables for the "gitea serv" command.
+	// it could be re-considered whether to use the same git.CommonGitCmdEnvs() as "git" command later.
+	gitcmd.Env = append(gitcmd.Env, git.CommonCmdServEnvs()...)
+
 	if err = gitcmd.Run(); err != nil {
 		return fail("Internal error", "Failed to execute git command: %v", err)
 	}
diff --git a/integrations/integration_test.go b/integrations/integration_test.go
index 687591d5fa..0a41546554 100644
--- a/integrations/integration_test.go
+++ b/integrations/integration_test.go
@@ -274,8 +274,8 @@ func prepareTestEnv(t testing.TB, skip ...int) func() {
 	deferFn := PrintCurrentTest(t, ourSkip)
 	assert.NoError(t, unittest.LoadFixtures())
 	assert.NoError(t, util.RemoveAll(setting.RepoRootPath))
-
 	assert.NoError(t, unittest.CopyDir(path.Join(filepath.Dir(setting.AppPath), "integrations/gitea-repositories-meta"), setting.RepoRootPath))
+	assert.NoError(t, git.InitWithConfigSync(context.Background()))
 	ownerDirs, err := os.ReadDir(setting.RepoRootPath)
 	if err != nil {
 		assert.NoError(t, err, "unable to read the new repo root: %v\n", err)
@@ -576,6 +576,7 @@ func resetFixtures(t *testing.T) {
 	assert.NoError(t, unittest.LoadFixtures())
 	assert.NoError(t, util.RemoveAll(setting.RepoRootPath))
 	assert.NoError(t, unittest.CopyDir(path.Join(filepath.Dir(setting.AppPath), "integrations/gitea-repositories-meta"), setting.RepoRootPath))
+	assert.NoError(t, git.InitWithConfigSync(context.Background()))
 	ownerDirs, err := os.ReadDir(setting.RepoRootPath)
 	if err != nil {
 		assert.NoError(t, err, "unable to read the new repo root: %v\n", err)
diff --git a/integrations/migration-test/migration_test.go b/integrations/migration-test/migration_test.go
index 6a431504a0..45e31ff9ac 100644
--- a/integrations/migration-test/migration_test.go
+++ b/integrations/migration-test/migration_test.go
@@ -62,6 +62,7 @@ func initMigrationTest(t *testing.T) func() {
 	assert.True(t, len(setting.RepoRootPath) != 0)
 	assert.NoError(t, util.RemoveAll(setting.RepoRootPath))
 	assert.NoError(t, unittest.CopyDir(path.Join(filepath.Dir(setting.AppPath), "integrations/gitea-repositories-meta"), setting.RepoRootPath))
+	assert.NoError(t, git.InitWithConfigSync(context.Background()))
 	ownerDirs, err := os.ReadDir(setting.RepoRootPath)
 	if err != nil {
 		assert.NoError(t, err, "unable to read the new repo root: %v\n", err)
diff --git a/models/migrations/migrations_test.go b/models/migrations/migrations_test.go
index a1fd49a8b9..2c4d21d974 100644
--- a/models/migrations/migrations_test.go
+++ b/models/migrations/migrations_test.go
@@ -202,9 +202,8 @@ func prepareTestEnv(t *testing.T, skip int, syncModels ...interface{}) (*xorm.En
 	ourSkip += skip
 	deferFn := PrintCurrentTest(t, ourSkip)
 	assert.NoError(t, os.RemoveAll(setting.RepoRootPath))
-
-	assert.NoError(t, unittest.CopyDir(path.Join(filepath.Dir(setting.AppPath), "integrations/gitea-repositories-meta"),
-		setting.RepoRootPath))
+	assert.NoError(t, unittest.CopyDir(path.Join(filepath.Dir(setting.AppPath), "integrations/gitea-repositories-meta"), setting.RepoRootPath))
+	assert.NoError(t, git.InitWithConfigSync(context.Background()))
 	ownerDirs, err := os.ReadDir(setting.RepoRootPath)
 	if err != nil {
 		assert.NoError(t, err, "unable to read the new repo root: %v\n", err)
diff --git a/models/unittest/testdb.go b/models/unittest/testdb.go
index 117614a7a4..2a366836fe 100644
--- a/models/unittest/testdb.go
+++ b/models/unittest/testdb.go
@@ -14,6 +14,7 @@ import (
 
 	"code.gitea.io/gitea/models/db"
 	"code.gitea.io/gitea/modules/base"
+	"code.gitea.io/gitea/modules/git"
 	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/modules/storage"
 	"code.gitea.io/gitea/modules/util"
@@ -116,6 +117,9 @@ func MainTest(m *testing.M, testOpts *TestOptions) {
 	if err = CopyDir(filepath.Join(testOpts.GiteaRootPath, "integrations", "gitea-repositories-meta"), setting.RepoRootPath); err != nil {
 		fatalTestError("util.CopyDir: %v\n", err)
 	}
+	if err = git.InitWithConfigSync(context.Background()); err != nil {
+		fatalTestError("git.Init: %v\n", err)
+	}
 
 	ownerDirs, err := os.ReadDir(setting.RepoRootPath)
 	if err != nil {
@@ -198,6 +202,7 @@ func PrepareTestEnv(t testing.TB) {
 	assert.NoError(t, util.RemoveAll(setting.RepoRootPath))
 	metaPath := filepath.Join(giteaRoot, "integrations", "gitea-repositories-meta")
 	assert.NoError(t, CopyDir(metaPath, setting.RepoRootPath))
+	assert.NoError(t, git.InitWithConfigSync(context.Background()))
 
 	ownerDirs, err := os.ReadDir(setting.RepoRootPath)
 	assert.NoError(t, err)
diff --git a/modules/git/command.go b/modules/git/command.go
index f6344dbfd1..d71497f1d7 100644
--- a/modules/git/command.go
+++ b/modules/git/command.go
@@ -8,6 +8,7 @@ package git
 import (
 	"bytes"
 	"context"
+	"errors"
 	"fmt"
 	"io"
 	"os"
@@ -104,6 +105,25 @@ type RunOpts struct {
 	PipelineFunc   func(context.Context, context.CancelFunc) error
 }
 
+// CommonGitCmdEnvs returns the common environment variables for a "git" command.
+func CommonGitCmdEnvs() []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)
+		"HOME=" + HomeDir(),        // make Gitea use internal git config only, to prevent conflicts with user's git config
+	}
+}
+
+// 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
+	}
+}
+
 // Run runs the command with the RunOpts
 func (c *Command) Run(opts *RunOpts) error {
 	if opts == nil {
@@ -148,16 +168,8 @@ func (c *Command) Run(opts *RunOpts) error {
 		cmd.Env = opts.Env
 	}
 
-	cmd.Env = append(
-		cmd.Env,
-		fmt.Sprintf("LC_ALL=%s", DefaultLocale),
-		// avoid prompting for credentials interactively, supported since git v2.3
-		"GIT_TERMINAL_PROMPT=0",
-		// ignore replace references (https://git-scm.com/docs/git-replace)
-		"GIT_NO_REPLACE_OBJECTS=1",
-	)
-
 	process.SetSysProcAttribute(cmd)
+	cmd.Env = append(cmd.Env, CommonGitCmdEnvs()...)
 	cmd.Dir = opts.Dir
 	cmd.Stdout = opts.Stdout
 	cmd.Stderr = opts.Stderr
@@ -184,7 +196,9 @@ func (c *Command) Run(opts *RunOpts) error {
 
 type RunStdError interface {
 	error
+	Unwrap() error
 	Stderr() string
+	IsExitCode(code int) bool
 }
 
 type runStdError struct {
@@ -209,6 +223,14 @@ func (r *runStdError) Stderr() string {
 	return r.stderr
 }
 
+func (r *runStdError) IsExitCode(code int) bool {
+	var exitError *exec.ExitError
+	if errors.As(r.err, &exitError) {
+		return exitError.ExitCode() == code
+	}
+	return false
+}
+
 func bytesToString(b []byte) string {
 	return *(*string)(unsafe.Pointer(&b)) // that's what Golang's strings.Builder.String() does (go/src/strings/builder.go)
 }
diff --git a/modules/git/commit.go b/modules/git/commit.go
index 8c194ef502..99fbbd0cfc 100644
--- a/modules/git/commit.go
+++ b/modules/git/commit.go
@@ -398,11 +398,6 @@ func (c *Commit) GetSubModule(entryname string) (*SubModule, error) {
 
 // GetBranchName gets the closest branch name (as returned by 'git name-rev --name-only')
 func (c *Commit) GetBranchName() (string, error) {
-	err := LoadGitVersion()
-	if err != nil {
-		return "", fmt.Errorf("Git version missing: %v", err)
-	}
-
 	args := []string{
 		"name-rev",
 	}
diff --git a/modules/git/git.go b/modules/git/git.go
index 8fad070330..5817bd2c7f 100644
--- a/modules/git/git.go
+++ b/modules/git/git.go
@@ -10,11 +10,13 @@ import (
 	"fmt"
 	"os"
 	"os/exec"
+	"path/filepath"
 	"runtime"
 	"strings"
+	"sync"
 	"time"
 
-	"code.gitea.io/gitea/modules/process"
+	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
 
 	"github.com/hashicorp/go-version"
@@ -32,38 +34,33 @@ var (
 	GitExecutable = "git"
 
 	// DefaultContext is the default context to run git commands in
-	// will be overwritten by Init with HammerContext
+	// will be overwritten by InitWithConfigSync with HammerContext
 	DefaultContext = context.Background()
 
-	gitVersion *version.Version
-
 	// SupportProcReceive version >= 2.29.0
 	SupportProcReceive bool
-)
 
-// LocalVersion returns current Git version from shell.
-func LocalVersion() (*version.Version, error) {
-	if err := LoadGitVersion(); err != nil {
-		return nil, err
-	}
-	return gitVersion, nil
-}
+	// initMutex is used to avoid Golang's data race error. see the comments below.
+	initMutex sync.Mutex
+
+	gitVersion *version.Version
+)
 
-// LoadGitVersion returns current Git version from shell.
-func LoadGitVersion() error {
+// loadGitVersion returns current Git version from shell. Internal usage only.
+func loadGitVersion() (*version.Version, error) {
 	// doesn't need RWMutex because its exec by Init()
 	if gitVersion != nil {
-		return nil
+		return gitVersion, nil
 	}
 
-	stdout, _, runErr := NewCommand(context.Background(), "version").RunStdString(nil)
+	stdout, _, runErr := NewCommand(DefaultContext, "version").RunStdString(nil)
 	if runErr != nil {
-		return runErr
+		return nil, runErr
 	}
 
 	fields := strings.Fields(stdout)
 	if len(fields) < 3 {
-		return fmt.Errorf("not enough output: %s", stdout)
+		return nil, fmt.Errorf("invalid git version output: %s", stdout)
 	}
 
 	var versionString string
@@ -78,7 +75,7 @@ func LoadGitVersion() error {
 
 	var err error
 	gitVersion, err = version.NewVersion(versionString)
-	return err
+	return gitVersion, err
 }
 
 // SetExecutablePath changes the path of git executable and checks the file permission and version.
@@ -93,7 +90,7 @@ func SetExecutablePath(path string) error {
 	}
 	GitExecutable = absPath
 
-	err = LoadGitVersion()
+	_, err = loadGitVersion()
 	if err != nil {
 		return fmt.Errorf("unable to load git version: %w", err)
 	}
@@ -120,7 +117,10 @@ func SetExecutablePath(path string) error {
 
 // VersionInfo returns git version information
 func VersionInfo() string {
-	format := "Git Version: %s"
+	if gitVersion == nil {
+		return "(git not found)"
+	}
+	format := "%s"
 	args := []interface{}{gitVersion.Original()}
 	// Since git wire protocol has been released from git v2.18
 	if setting.Git.EnableAutoGitWireProtocol && CheckGitVersionAtLeast("2.18") == nil {
@@ -131,8 +131,33 @@ func VersionInfo() string {
 	return fmt.Sprintf(format, args...)
 }
 
-// Init initializes git module
-func Init(ctx context.Context) error {
+// InitSimple initializes git module with a very simple step, no config changes, no global command arguments.
+// This method doesn't change anything to filesystem
+func InitSimple(ctx context.Context) error {
+	initMutex.Lock()
+	defer initMutex.Unlock()
+
+	return initSimpleInternal(ctx)
+}
+
+// HomeDir is the home dir for git to store the global config file used by Gitea internally
+func HomeDir() string {
+	if setting.RepoRootPath == "" {
+		// TODO: now, some unit test code call the git module directly without initialization, which is incorrect.
+		// at the moment, we just use a temp HomeDir to prevent from conflicting with user's git config
+		// in the future, the git module should be initialized first before use.
+		tmpHomeDir := filepath.Join(os.TempDir(), "gitea-temp-home")
+		log.Error("Git's HomeDir is empty (RepoRootPath is empty), the git module is not initialized correctly, using a temp HomeDir (%s) temporarily", tmpHomeDir)
+		return tmpHomeDir
+	}
+	return setting.RepoRootPath
+}
+
+func initSimpleInternal(ctx context.Context) error {
+	// at the moment, when running integration tests, the git.InitXxx would be called twice.
+	// one is called by the GlobalInitInstalled, one is called by TestMain.
+	// so the init functions should be protected by a mutex to avoid Golang's data race error.
+
 	DefaultContext = ctx
 
 	if setting.Git.Timeout.Default > 0 {
@@ -146,6 +171,23 @@ func Init(ctx context.Context) error {
 	// force cleanup args
 	globalCommandArgs = []string{}
 
+	return nil
+}
+
+// InitWithConfigSync initializes git module. This method may create directories or write files into filesystem
+func InitWithConfigSync(ctx context.Context) error {
+	initMutex.Lock()
+	defer initMutex.Unlock()
+
+	err := initSimpleInternal(ctx)
+	if err != nil {
+		return err
+	}
+
+	if err = os.MkdirAll(setting.RepoRootPath, os.ModePerm); err != nil {
+		return fmt.Errorf("unable to create directory %s, err: %w", setting.RepoRootPath, err)
+	}
+
 	if CheckGitVersionAtLeast("2.9") == nil {
 		// Explicitly disable credential helper, otherwise Git credentials might leak
 		globalCommandArgs = append(globalCommandArgs, "-c", "credential.helper=")
@@ -161,68 +203,71 @@ func Init(ctx context.Context) error {
 		globalCommandArgs = append(globalCommandArgs, "-c", "uploadpack.allowfilter=true", "-c", "uploadpack.allowAnySHA1InWant=true")
 	}
 
-	// Save current git version on init to gitVersion otherwise it would require an RWMutex
-	if err := LoadGitVersion(); err != nil {
-		return err
-	}
-
-	// Git requires setting user.name and user.email in order to commit changes - if they're not set just add some defaults
-	for configKey, defaultValue := range map[string]string{"user.name": "Gitea", "user.email": "gitea@fake.local"} {
-		if err := checkAndSetConfig(configKey, defaultValue, false); err != nil {
+	// Git requires setting user.name and user.email in order to commit changes - old comment: "if they're not set just add some defaults"
+	// TODO: need to confirm whether users really need to change these values manually. It seems that these values are dummy only and not really used.
+	// If these values are not really used, then they can be set (overwritten) directly without considering about existence.
+	for configKey, defaultValue := range map[string]string{
+		"user.name":  "Gitea",
+		"user.email": "gitea@fake.local",
+	} {
+		if err := configSetNonExist(configKey, defaultValue); err != nil {
 			return err
 		}
 	}
 
 	// Set git some configurations - these must be set to these values for gitea to work correctly
-	if err := checkAndSetConfig("core.quotePath", "false", true); err != nil {
+	if err := configSet("core.quotePath", "false"); err != nil {
 		return err
 	}
 
 	if CheckGitVersionAtLeast("2.10") == nil {
-		if err := checkAndSetConfig("receive.advertisePushOptions", "true", true); err != nil {
+		if err := configSet("receive.advertisePushOptions", "true"); err != nil {
 			return err
 		}
 	}
 
 	if CheckGitVersionAtLeast("2.18") == nil {
-		if err := checkAndSetConfig("core.commitGraph", "true", true); err != nil {
+		if err := configSet("core.commitGraph", "true"); err != nil {
 			return err
 		}
-		if err := checkAndSetConfig("gc.writeCommitGraph", "true", true); err != nil {
+		if err := configSet("gc.writeCommitGraph", "true"); err != nil {
 			return err
 		}
 	}
 
 	if CheckGitVersionAtLeast("2.29") == nil {
 		// set support for AGit flow
-		if err := checkAndAddConfig("receive.procReceiveRefs", "refs/for"); err != nil {
+		if err := configAddNonExist("receive.procReceiveRefs", "refs/for"); err != nil {
 			return err
 		}
 		SupportProcReceive = true
 	} else {
-		if err := checkAndRemoveConfig("receive.procReceiveRefs", "refs/for"); err != nil {
+		if err := configUnsetAll("receive.procReceiveRefs", "refs/for"); err != nil {
 			return err
 		}
 		SupportProcReceive = false
 	}
 
 	if runtime.GOOS == "windows" {
-		if err := checkAndSetConfig("core.longpaths", "true", true); err != nil {
+		if err := configSet("core.longpaths", "true"); err != nil {
 			return err
 		}
-	}
-	if setting.Git.DisableCoreProtectNTFS {
-		if err := checkAndSetConfig("core.protectntfs", "false", true); err != nil {
+		if setting.Git.DisableCoreProtectNTFS {
+			err = configSet("core.protectNTFS", "false")
+		} else {
+			err = configUnsetAll("core.protectNTFS", "false")
+		}
+		if err != nil {
 			return err
 		}
-		globalCommandArgs = append(globalCommandArgs, "-c", "core.protectntfs=false")
 	}
+
 	return nil
 }
 
 // CheckGitVersionAtLeast check git version is at least the constraint version
 func CheckGitVersionAtLeast(atLeast string) error {
-	if err := LoadGitVersion(); err != nil {
+	if _, err := loadGitVersion(); err != nil {
 		return err
 	}
 	atLeastVersion, err := version.NewVersion(atLeast)
@@ -235,75 +280,75 @@ func CheckGitVersionAtLeast(atLeast string) error {
 	return nil
 }
 
-func checkAndSetConfig(key, defaultValue string, forceToDefault bool) error {
-	stdout, stderr, err := process.GetManager().Exec("git.Init(get setting)", GitExecutable, "config", "--get", key)
-	if err != nil {
-		perr, ok := err.(*process.Error)
-		if !ok {
-			return fmt.Errorf("Failed to get git %s(%v) errType %T: %s", key, err, err, stderr)
-		}
-		eerr, ok := perr.Err.(*exec.ExitError)
-		if !ok || eerr.ExitCode() != 1 {
-			return fmt.Errorf("Failed to get git %s(%v) errType %T: %s", key, err, err, stderr)
-		}
+func configSet(key, value string) error {
+	stdout, _, err := NewCommand(DefaultContext, "config", "--get", key).RunStdString(nil)
+	if err != nil && !err.IsExitCode(1) {
+		return fmt.Errorf("failed to get git config %s, err: %w", key, err)
 	}
 
 	currValue := strings.TrimSpace(stdout)
-
-	if currValue == defaultValue || (!forceToDefault && len(currValue) > 0) {
+	if currValue == value {
 		return nil
 	}
 
-	if _, stderr, err = process.GetManager().Exec(fmt.Sprintf("git.Init(set %s)", key), "git", "config", "--global", key, defaultValue); err != nil {
-		return fmt.Errorf("Failed to set git %s(%s): %s", key, err, stderr)
+	_, _, err = NewCommand(DefaultContext, "config", "--global", key, value).RunStdString(nil)
+	if err != nil {
+		return fmt.Errorf("failed to set git global config %s, err: %w", key, err)
 	}
 
 	return nil
 }
 
-func checkAndAddConfig(key, value string) error {
-	_, stderr, err := process.GetManager().Exec("git.Init(get setting)", GitExecutable, "config", "--get", key, value)
-	if err != nil {
-		perr, ok := err.(*process.Error)
-		if !ok {
-			return fmt.Errorf("Failed to get git %s(%v) errType %T: %s", key, err, err, stderr)
-		}
-		eerr, ok := perr.Err.(*exec.ExitError)
-		if !ok || eerr.ExitCode() != 1 {
-			return fmt.Errorf("Failed to get git %s(%v) errType %T: %s", key, err, err, stderr)
-		}
-		if eerr.ExitCode() == 1 {
-			if _, stderr, err = process.GetManager().Exec(fmt.Sprintf("git.Init(set %s)", key), "git", "config", "--global", "--add", key, value); err != nil {
-				return fmt.Errorf("Failed to set git %s(%s): %s", key, err, stderr)
-			}
-			return nil
+func configSetNonExist(key, value string) error {
+	_, _, err := NewCommand(DefaultContext, "config", "--get", key).RunStdString(nil)
+	if err == nil {
+		// already exist
+		return nil
+	}
+	if err.IsExitCode(1) {
+		// not exist, set new config
+		_, _, err = NewCommand(DefaultContext, "config", "--global", key, value).RunStdString(nil)
+		if err != nil {
+			return fmt.Errorf("failed to set git global config %s, err: %w", key, err)
 		}
+		return nil
 	}
 
-	return nil
+	return fmt.Errorf("failed to get git config %s, err: %w", key, err)
 }
 
-func checkAndRemoveConfig(key, value string) error {
-	_, stderr, err := process.GetManager().Exec("git.Init(get setting)", GitExecutable, "config", "--get", key, value)
-	if err != nil {
-		perr, ok := err.(*process.Error)
-		if !ok {
-			return fmt.Errorf("Failed to get git %s(%v) errType %T: %s", key, err, err, stderr)
-		}
-		eerr, ok := perr.Err.(*exec.ExitError)
-		if !ok || eerr.ExitCode() != 1 {
-			return fmt.Errorf("Failed to get git %s(%v) errType %T: %s", key, err, err, stderr)
-		}
-		if eerr.ExitCode() == 1 {
-			return nil
+func configAddNonExist(key, value string) error {
+	_, _, err := NewCommand(DefaultContext, "config", "--fixed-value", "--get", key, value).RunStdString(nil)
+	if err == nil {
+		// already exist
+		return nil
+	}
+	if err.IsExitCode(1) {
+		// not exist, add new config
+		_, _, err = NewCommand(DefaultContext, "config", "--global", "--add", key, value).RunStdString(nil)
+		if err != nil {
+			return fmt.Errorf("failed to add git global config %s, err: %w", key, err)
 		}
+		return nil
 	}
+	return fmt.Errorf("failed to get git config %s, err: %w", key, err)
+}
 
-	if _, stderr, err = process.GetManager().Exec(fmt.Sprintf("git.Init(set %s)", key), "git", "config", "--global", "--unset-all", key, value); err != nil {
-		return fmt.Errorf("Failed to set git %s(%s): %s", key, err, stderr)
+func configUnsetAll(key, value string) error {
+	_, _, err := NewCommand(DefaultContext, "config", "--get", key).RunStdString(nil)
+	if err == nil {
+		// exist, need to remove
+		_, _, err = NewCommand(DefaultContext, "config", "--global", "--fixed-value", "--unset-all", key, value).RunStdString(nil)
+		if err != nil {
+			return fmt.Errorf("failed to unset git global config %s, err: %w", key, err)
+		}
+		return nil
 	}
-
-	return nil
+	if err.IsExitCode(1) {
+		// not exist
+		return nil
+	}
+	return fmt.Errorf("failed to get git config %s, err: %w", key, err)
 }
 
 // Fsck verifies the connectivity and validity of the objects in the database
diff --git a/modules/git/git_test.go b/modules/git/git_test.go
index c62a55badc..5b1cd820e8 100644
--- a/modules/git/git_test.go
+++ b/modules/git/git_test.go
@@ -8,23 +8,74 @@ import (
 	"context"
 	"fmt"
 	"os"
+	"strings"
 	"testing"
 
 	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/util"
+
+	"github.com/stretchr/testify/assert"
 )
 
-func fatalTestError(fmtStr string, args ...interface{}) {
-	fmt.Fprintf(os.Stderr, fmtStr, args...)
-	os.Exit(1)
+func testRun(m *testing.M) error {
+	_ = log.NewLogger(1000, "console", "console", `{"level":"trace","stacktracelevel":"NONE","stderr":true}`)
+
+	repoRootPath, err := os.MkdirTemp(os.TempDir(), "repos")
+	if err != nil {
+		return fmt.Errorf("unable to create temp dir: %w", err)
+	}
+	defer util.RemoveAll(repoRootPath)
+	setting.RepoRootPath = repoRootPath
+
+	if err = InitWithConfigSync(context.Background()); err != nil {
+		return fmt.Errorf("failed to call Init: %w", err)
+	}
+
+	exitCode := m.Run()
+	if exitCode != 0 {
+		return fmt.Errorf("run test failed, ExitCode=%d", exitCode)
+	}
+	return nil
 }
 
 func TestMain(m *testing.M) {
-	_ = log.NewLogger(1000, "console", "console", `{"level":"trace","stacktracelevel":"NONE","stderr":true}`)
+	if err := testRun(m); err != nil {
+		_, _ = fmt.Fprintf(os.Stderr, "Test failed: %v", err)
+		os.Exit(1)
+	}
+}
 
-	if err := Init(context.Background()); err != nil {
-		fatalTestError("Init failed: %v", err)
+func TestGitConfig(t *testing.T) {
+	gitConfigContains := func(sub string) bool {
+		if b, err := os.ReadFile(HomeDir() + "/.gitconfig"); err == nil {
+			return strings.Contains(string(b), sub)
+		}
+		return false
 	}
 
-	exitStatus := m.Run()
-	os.Exit(exitStatus)
+	assert.False(t, gitConfigContains("key-a"))
+
+	assert.NoError(t, configSetNonExist("test.key-a", "val-a"))
+	assert.True(t, gitConfigContains("key-a = val-a"))
+
+	assert.NoError(t, configSetNonExist("test.key-a", "val-a-changed"))
+	assert.False(t, gitConfigContains("key-a = val-a-changed"))
+
+	assert.NoError(t, configSet("test.key-a", "val-a-changed"))
+	assert.True(t, gitConfigContains("key-a = val-a-changed"))
+
+	assert.NoError(t, configAddNonExist("test.key-b", "val-b"))
+	assert.True(t, gitConfigContains("key-b = val-b"))
+
+	assert.NoError(t, configAddNonExist("test.key-b", "val-2b"))
+	assert.True(t, gitConfigContains("key-b = val-b"))
+	assert.True(t, gitConfigContains("key-b = val-2b"))
+
+	assert.NoError(t, configUnsetAll("test.key-b", "val-b"))
+	assert.False(t, gitConfigContains("key-b = val-b"))
+	assert.True(t, gitConfigContains("key-b = val-2b"))
+
+	assert.NoError(t, configUnsetAll("test.key-b", "val-2b"))
+	assert.False(t, gitConfigContains("key-b = val-2b"))
 }
diff --git a/modules/git/lfs.go b/modules/git/lfs.go
index cdd9d15b2e..c5d8354b6d 100644
--- a/modules/git/lfs.go
+++ b/modules/git/lfs.go
@@ -18,12 +18,6 @@ func CheckLFSVersion() {
 	if setting.LFS.StartServer {
 		// Disable LFS client hooks if installed for the current OS user
 		// Needs at least git v2.1.2
-
-		err := LoadGitVersion()
-		if err != nil {
-			logger.Fatal("Error retrieving git version: %v", err)
-		}
-
 		if CheckGitVersionAtLeast("2.1.2") != nil {
 			setting.LFS.StartServer = false
 			logger.Error("LFS server support needs at least Git v2.1.2")
diff --git a/modules/git/remote.go b/modules/git/remote.go
index 536b1681ce..b2a2e6d7ab 100644
--- a/modules/git/remote.go
+++ b/modules/git/remote.go
@@ -11,10 +11,6 @@ import (
 
 // GetRemoteAddress returns the url of a specific remote of the repository.
 func GetRemoteAddress(ctx context.Context, repoPath, remoteName string) (*url.URL, error) {
-	err := LoadGitVersion()
-	if err != nil {
-		return nil, err
-	}
 	var cmd *Command
 	if CheckGitVersionAtLeast("2.7") == nil {
 		cmd = NewCommand(ctx, "remote", "get-url", remoteName)
diff --git a/modules/git/repo_attribute.go b/modules/git/repo_attribute.go
index a18c80c3f1..38818788f3 100644
--- a/modules/git/repo_attribute.go
+++ b/modules/git/repo_attribute.go
@@ -28,11 +28,6 @@ type CheckAttributeOpts struct {
 
 // CheckAttribute return the Blame object of file
 func (repo *Repository) CheckAttribute(opts CheckAttributeOpts) (map[string]map[string]string, error) {
-	err := LoadGitVersion()
-	if err != nil {
-		return nil, fmt.Errorf("git version missing: %v", err)
-	}
-
 	env := []string{}
 
 	if len(opts.IndexFile) > 0 && CheckGitVersionAtLeast("1.7.8") == nil {
@@ -126,7 +121,7 @@ type CheckAttributeReader struct {
 	cancel      context.CancelFunc
 }
 
-// Init initializes the cmd
+// Init initializes the CheckAttributeReader
 func (c *CheckAttributeReader) Init(ctx context.Context) error {
 	cmdArgs := []string{"check-attr", "--stdin", "-z"}
 
diff --git a/modules/git/repo_tree.go b/modules/git/repo_tree.go
index 3e7a9c2cfb..2e139daddf 100644
--- a/modules/git/repo_tree.go
+++ b/modules/git/repo_tree.go
@@ -24,11 +24,6 @@ type CommitTreeOpts struct {
 
 // CommitTree creates a commit from a given tree id for the user with provided message
 func (repo *Repository) CommitTree(author, committer *Signature, tree *Tree, opts CommitTreeOpts) (SHA1, error) {
-	err := LoadGitVersion()
-	if err != nil {
-		return SHA1{}, err
-	}
-
 	commitTimeStr := time.Now().Format(time.RFC3339)
 
 	// Because this may call hooks we should pass in the environment
@@ -60,14 +55,13 @@ func (repo *Repository) CommitTree(author, committer *Signature, tree *Tree, opt
 
 	stdout := new(bytes.Buffer)
 	stderr := new(bytes.Buffer)
-	err = cmd.Run(&RunOpts{
+	err := cmd.Run(&RunOpts{
 		Env:    env,
 		Dir:    repo.Path,
 		Stdin:  messageBytes,
 		Stdout: stdout,
 		Stderr: stderr,
 	})
-
 	if err != nil {
 		return SHA1{}, ConcatenateError(err, stderr.String())
 	}
diff --git a/modules/indexer/stats/indexer_test.go b/modules/indexer/stats/indexer_test.go
index 9d9de5413c..a335972c21 100644
--- a/modules/indexer/stats/indexer_test.go
+++ b/modules/indexer/stats/indexer_test.go
@@ -30,7 +30,7 @@ func TestMain(m *testing.M) {
 }
 
 func TestRepoStatsIndex(t *testing.T) {
-	if err := git.Init(context.Background()); !assert.NoError(t, err) {
+	if err := git.InitWithConfigSync(context.Background()); !assert.NoError(t, err) {
 		return
 	}
 
diff --git a/modules/repository/init.go b/modules/repository/init.go
index f8c7a89552..285fe81dbe 100644
--- a/modules/repository/init.go
+++ b/modules/repository/init.go
@@ -317,11 +317,6 @@ func initRepoCommit(ctx context.Context, tmpPath string, repo *repo_model.Reposi
 		return fmt.Errorf("git add --all: %v", err)
 	}
 
-	err = git.LoadGitVersion()
-	if err != nil {
-		return fmt.Errorf("Unable to get git version: %v", err)
-	}
-
 	args := []string{
 		"commit", fmt.Sprintf("--author='%s <%s>'", sig.Name, sig.Email),
 		"-m", "Initial commit",
diff --git a/modules/util/path.go b/modules/util/path.go
index ed7cc62699..0ccc7a1dc2 100644
--- a/modules/util/path.go
+++ b/modules/util/path.go
@@ -182,6 +182,7 @@ func FileURLToPath(u *url.URL) (string, error) {
 // it returns error when the variable does not exist.
 func HomeDir() (home string, err error) {
 	// TODO: some users run Gitea with mismatched uid  and "HOME=xxx" (they set HOME=xxx by environment manually)
+	// TODO: when running gitea as a sub command inside git, the HOME directory is not the user's home directory
 	// so at the moment we can not use `user.Current().HomeDir`
 	if isOSWindows() {
 		home = os.Getenv("USERPROFILE")
diff --git a/routers/init.go b/routers/init.go
index 6036499362..9b6a770f27 100644
--- a/routers/init.go
+++ b/routers/init.go
@@ -102,8 +102,8 @@ func GlobalInitInstalled(ctx context.Context) {
 		log.Fatal("Gitea is not installed")
 	}
 
-	mustInitCtx(ctx, git.Init)
-	log.Info(git.VersionInfo())
+	mustInitCtx(ctx, git.InitWithConfigSync)
+	log.Info("Git Version: %s (home: %s)", git.VersionInfo(), git.HomeDir())
 
 	git.CheckLFSVersion()
 	log.Info("AppPath: %s", setting.AppPath)
diff --git a/routers/web/admin/admin.go b/routers/web/admin/admin.go
index 78347e67c4..24c07b5c1c 100644
--- a/routers/web/admin/admin.go
+++ b/routers/web/admin/admin.go
@@ -247,9 +247,8 @@ func Config(ctx *context.Context) {
 	ctx.Data["DisableRouterLog"] = setting.DisableRouterLog
 	ctx.Data["RunUser"] = setting.RunUser
 	ctx.Data["RunMode"] = util.ToTitleCase(setting.RunMode)
-	if version, err := git.LocalVersion(); err == nil {
-		ctx.Data["GitVersion"] = version.Original()
-	}
+	ctx.Data["GitVersion"] = git.VersionInfo()
+
 	ctx.Data["RepoRootPath"] = setting.RepoRootPath
 	ctx.Data["CustomRootPath"] = setting.CustomPath
 	ctx.Data["StaticRootPath"] = setting.StaticRootPath
diff --git a/routers/web/repo/lfs.go b/routers/web/repo/lfs.go
index 7c2ff1cfae..e2421f1389 100644
--- a/routers/web/repo/lfs.go
+++ b/routers/web/repo/lfs.go
@@ -421,12 +421,9 @@ func LFSPointerFiles(ctx *context.Context) {
 		return
 	}
 	ctx.Data["PageIsSettingsLFS"] = true
-	err := git.LoadGitVersion()
-	if err != nil {
-		log.Fatal("Error retrieving git version: %v", err)
-	}
 	ctx.Data["LFSFilesLink"] = ctx.Repo.RepoLink + "/settings/lfs"
 
+	var err error
 	err = func() error {
 		pointerChan := make(chan lfs.PointerBlob)
 		errChan := make(chan error, 1)
diff --git a/services/pull/merge.go b/services/pull/merge.go
index fcced65cdf..76798d73ed 100644
--- a/services/pull/merge.go
+++ b/services/pull/merge.go
@@ -223,12 +223,6 @@ func Merge(ctx context.Context, pr *models.PullRequest, doer *user_model.User, b
 
 // rawMerge perform the merge operation without changing any pull information in database
 func rawMerge(ctx context.Context, pr *models.PullRequest, doer *user_model.User, mergeStyle repo_model.MergeStyle, expectedHeadCommitID, message string) (string, error) {
-	err := git.LoadGitVersion()
-	if err != nil {
-		log.Error("git.LoadGitVersion: %v", err)
-		return "", fmt.Errorf("Unable to get git version: %v", err)
-	}
-
 	// Clone base repo.
 	tmpBasePath, err := createTemporaryRepo(ctx, pr)
 	if err != nil {
diff --git a/services/repository/files/temp_repo.go b/services/repository/files/temp_repo.go
index 9c7d9aafec..97a80a96bd 100644
--- a/services/repository/files/temp_repo.go
+++ b/services/repository/files/temp_repo.go
@@ -229,11 +229,6 @@ func (t *TemporaryUploadRepository) CommitTreeWithDate(parent string, author, co
 	authorSig := author.NewGitSig()
 	committerSig := committer.NewGitSig()
 
-	err := git.LoadGitVersion()
-	if err != nil {
-		return "", fmt.Errorf("Unable to get git version: %v", err)
-	}
-
 	// Because this may call hooks we should pass in the environment
 	env := append(os.Environ(),
 		"GIT_AUTHOR_NAME="+authorSig.Name,