Support reflogs (#22451)

This PR adds support for reflogs on all repositories. It does this by
adding a global configuration entry.

Implements #14865

---------

Signed-off-by: Philip Peterson <philip.c.peterson@gmail.com>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

6 files changed, 71 insertions, 3 deletions

diff --git a/custom/conf/app.example.ini b/custom/conf/app.example.ini
index c3c20a216c..b2b5af0af8 100644
--- a/custom/conf/app.example.ini
+++ b/custom/conf/app.example.ini
@@ -2272,6 +2272,17 @@ ROUTER = console
 ;PULL = 300
 ;GC = 60
 
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; Git Reflog timeout in days
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;[git.reflog]
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;ENABLED = true
+;EXPIRATION = 90
+
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;[mirror]
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 a5ef977f15..b67d6cdf5f 100644
--- a/docs/content/doc/advanced/config-cheat-sheet.en-us.md
+++ b/docs/content/doc/advanced/config-cheat-sheet.en-us.md
@@ -1093,6 +1093,11 @@ Default templates for project boards:
 - `DISABLE_CORE_PROTECT_NTFS`: **false** Set to true to forcibly set `core.protectNTFS` to false.
 - `DISABLE_PARTIAL_CLONE`: **false** Disable the usage of using partial clones for git.
 
+## Git - Reflog settings (`git.reflog`)
+
+- `ENABLED`: **true** Set to true to enable Git to write changes to reflogs in each repo.
+- `EXPIRATION`: **90** Reflog entry lifetime, in days. Entries are removed opportunistically by Git.
+
 ## Git - Timeout settings (`git.timeout`)
 
 - `DEFAULT`: **360**: Git operations default timeout seconds.
diff --git a/modules/git/git.go b/modules/git/git.go
index 24cfea8c7f..a31afc077a 100644
--- a/modules/git/git.go
+++ b/modules/git/git.go
@@ -201,6 +201,23 @@ func InitFull(ctx context.Context) (err error) {
 	return syncGitConfig()
 }
 
+func enableReflogs() error {
+	if err := configSet("core.logAllRefUpdates", "true"); err != nil {
+		return err
+	}
+	err := configSet("gc.reflogExpire", fmt.Sprintf("%d", setting.Git.Reflog.Expiration))
+	return err
+}
+
+func disableReflogs() error {
+	if err := configUnsetAll("core.logAllRefUpdates", "true"); err != nil {
+		return err
+	} else if err := configUnsetAll("gc.reflogExpire", ""); err != nil {
+		return err
+	}
+	return nil
+}
+
 // 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 {
@@ -224,6 +241,16 @@ func syncGitConfig() (err error) {
 		return err
 	}
 
+	if setting.Git.Reflog.Enabled {
+		if err := enableReflogs(); err != nil {
+			return err
+		}
+	} else {
+		if err := disableReflogs(); err != nil {
+			return err
+		}
+	}
+
 	if CheckGitVersionAtLeast("2.10") == nil {
 		if err := configSet("receive.advertisePushOptions", "true"); err != nil {
 			return err
diff --git a/modules/setting/git.go b/modules/setting/git.go
index 457b35936e..b8e7bb9cf8 100644
--- a/modules/setting/git.go
+++ b/modules/setting/git.go
@@ -12,9 +12,13 @@ import (
 
 // Git settings
 var Git = struct {
-	Path                      string
-	HomePath                  string
-	DisableDiffHighlight      bool
+	Path                 string
+	HomePath             string
+	DisableDiffHighlight bool
+	Reflog               struct {
+		Enabled    bool
+		Expiration int
+	} `ini:"git.reflog"`
 	MaxGitDiffLines           int
 	MaxGitDiffLineCharacters  int
 	MaxGitDiffFiles           int
@@ -37,6 +41,13 @@ var Git = struct {
 		GC      int `ini:"GC"`
 	} `ini:"git.timeout"`
 }{
+	Reflog: struct {
+		Enabled    bool
+		Expiration int
+	}{
+		Enabled:    true,
+		Expiration: 90,
+	},
 	DisableDiffHighlight:      false,
 	MaxGitDiffLines:           1000,
 	MaxGitDiffLineCharacters:  5000,
diff --git a/options/locale/locale_en-US.ini b/options/locale/locale_en-US.ini
index dccf184335..677af1397d 100644
--- a/options/locale/locale_en-US.ini
+++ b/options/locale/locale_en-US.ini
@@ -2934,6 +2934,8 @@ config.git_disable_diff_highlight = Disable Diff Syntax Highlight
 config.git_max_diff_lines = Max Diff Lines (for a single file)
 config.git_max_diff_line_characters = Max Diff Characters (for a single line)
 config.git_max_diff_files = Max Diff Files (to be shown)
+config.git_enable_reflogs = Enable Reflogs
+config.git_reflog_expiry_time = Expiry Time
 config.git_gc_args = GC Arguments
 config.git_migrate_timeout = Migration Timeout
 config.git_mirror_timeout = Mirror Update Timeout
diff --git a/templates/admin/config.tmpl b/templates/admin/config.tmpl
index 8f572c8396..cc0580cc19 100644
--- a/templates/admin/config.tmpl
+++ b/templates/admin/config.tmpl
@@ -331,7 +331,19 @@
 				<dd>{{.Git.MaxGitDiffFiles}}</dd>
 				<dt>{{.locale.Tr "admin.config.git_gc_args"}}</dt>
 				<dd><code>{{.Git.GCArgs}}</code></dd>
+
 				<div class="ui divider"></div>
+
+				<dt>{{.locale.Tr "admin.config.git_enable_reflogs"}}</dt>
+				<dd>{{if .Git.Reflog.Enabled}}{{svg "octicon-check"}}{{else}}{{svg "octicon-x"}}{{end}}</dd>
+
+				{{if .Git.Reflog.Enabled}}
+					<dt>{{.locale.Tr "admin.config.git_reflog_expiry_time"}}</dt>
+					<dd>{{.locale.Tr "tool.days" .Git.Reflog.Expiration}}</dd>
+				{{end}}
+
+				<div class="ui divider"></div>
+
 				<dt>{{.locale.Tr "admin.config.git_migrate_timeout"}}</dt>
 				<dd>{{.Git.Timeout.Migrate}} {{.locale.Tr "tool.raw_seconds"}}</dd>
 				<dt>{{.locale.Tr "admin.config.git_mirror_timeout"}}</dt>