fix(git): match git config values exactly when syncing (#39728) (#39729)

Backport #39728 by @silverwind

Since https://github.com/go-gitea/gitea/pull/39703, Gitea fails to start
when its gitconfig holds a `gc.reflogExpire` other than `90` (e.g.
`30.days`), because `git config --unset-all` exits 5 when no value
matches. Value patterns were also unanchored regexps, so `90` also
removed `90.days`.

- Match values exactly in `configUnsetAll` and `configAddNonExist`
- Treat "nothing to unset" as success
- Use `--replace-all` in `configSet` so a key with multiple values no
longer fails startup

Co-authored-by: silverwind <me@silverwind.io>

modules/git/config.go

@@ -167,7 +167,7 @@ func configSet(ctx context.Context, key, value string) error {
 		return nil
 	}
 
-	if _, _, err = gitcmd.NewCommand("config", "--global").
+	if _, _, err = gitcmd.NewCommand("config", "--global", "--replace-all").
 		AddDynamicArguments(key, value).
 		RunStdString(ctx); err != nil {
 		return fmt.Errorf("failed to set git global config %s, err: %w", key, err)
@@ -195,7 +195,7 @@ func configSetNonExist(ctx context.Context, key, value string) error {
 }
 
 func configAddNonExist(ctx context.Context, key, value string) error {
-	_, _, err := gitcmd.NewCommand("config", "--global", "--get").AddDynamicArguments(key, regexp.QuoteMeta(value)).RunStdString(ctx)
+	_, _, err := gitcmd.NewCommand("config", "--global", "--get").AddDynamicArguments(key, "^"+regexp.QuoteMeta(value)+"$").RunStdString(ctx)
 	if err == nil {
 		// already exist
 		return nil
@@ -212,18 +212,9 @@ func configAddNonExist(ctx context.Context, key, value string) error {
 }
 
 func configUnsetAll(ctx context.Context, key, value string) error {
-	_, _, err := gitcmd.NewCommand("config", "--global", "--get").AddDynamicArguments(key).RunStdString(ctx)
-	if err == nil {
-		// exist, need to remove
-		_, _, err = gitcmd.NewCommand("config", "--global", "--unset-all").AddDynamicArguments(key, regexp.QuoteMeta(value)).RunStdString(ctx)
-		if err != nil {
-			return fmt.Errorf("failed to unset git global config %s, err: %w", key, err)
-		}
-		return nil
+	_, _, err := gitcmd.NewCommand("config", "--global", "--unset-all").AddDynamicArguments(key, "^"+regexp.QuoteMeta(value)+"$").RunStdString(ctx)
+	if err != nil && !gitcmd.IsErrorExitCode(err, 5) { // 5: no such key or no matching value
+		return fmt.Errorf("failed to unset git global config %s, err: %w", key, err)
 	}
-	if gitcmd.IsErrorExitCode(err, 1) {
-		// not exist
-		return nil
-	}
-	return fmt.Errorf("failed to get git config %s, err: %w", key, err)
+	return nil
 }

modules/git/config_test.go

@@ -32,7 +32,9 @@ func TestGitConfig(t *testing.T) {
 	assert.NoError(t, configSetNonExist(ctx, "test.key-a", "val-a-changed"))
 	assert.False(t, gitConfigContains("key-a = val-a-changed"))
 
+	assert.NoError(t, configAddNonExist(ctx, "test.key-a", "val-a2"))
 	assert.NoError(t, configSet(ctx, "test.key-a", "val-a-changed"))
+	assert.NoError(t, configUnsetAll(ctx, "test.key-a", "val-a"))
 	assert.True(t, gitConfigContains("key-a = val-a-changed"))
 
 	assert.NoError(t, configAddNonExist(ctx, "test.key-b", "val-b"))
@@ -41,6 +43,8 @@ func TestGitConfig(t *testing.T) {
 	assert.NoError(t, configAddNonExist(ctx, "test.key-b", "val-2b"))
 	assert.True(t, gitConfigContains("key-b = val-b"))
 	assert.True(t, gitConfigContains("key-b = val-2b"))
+	assert.NoError(t, configAddNonExist(ctx, "test.key-b", "val"))
+	assert.True(t, gitConfigContains("key-b = val\n"))
 
 	assert.NoError(t, configUnsetAll(ctx, "test.key-b", "val-b"))
 	assert.False(t, gitConfigContains("key-b = val-b"))