3 files changed, 13 insertions, 7 deletions
diff --git a/services/pull/merge.go b/services/pull/merge.go
index 829d4b7ee1..2a2f47e880 100644
--- a/services/pull/merge.go
+++ b/services/pull/merge.go
@@ -432,10 +432,13 @@ func doMergeAndPush(ctx context.Context, pr *issues_model.PullRequest, doer *use
 
 func commitAndSignNoAuthor(ctx *mergeContext, message string) error {
 	cmdCommit := git.NewCommand("commit").AddOptionFormat("--message=%s", message)
-	if ctx.signKeyID == "" {
+	if ctx.signKey == nil {
 		cmdCommit.AddArguments("--no-gpg-sign")
 	} else {
-		cmdCommit.AddOptionFormat("-S%s", ctx.signKeyID)
+		if ctx.signKey.Format != "" {
+			cmdCommit.AddConfig("gpg.format", ctx.signKey.Format)
+		}
+		cmdCommit.AddOptionFormat("-S%s", ctx.signKey.KeyID)
 	}
 	if err := cmdCommit.Run(ctx, ctx.RunOpts()); err != nil {
 		log.Error("git commit %-v: %v\n%s\n%s", ctx.pr, err, ctx.outbuf.String(), ctx.errbuf.String())
diff --git a/services/pull/merge_prepare.go b/services/pull/merge_prepare.go
index 719cc6b965..31a1e13734 100644
--- a/services/pull/merge_prepare.go
+++ b/services/pull/merge_prepare.go
@@ -27,7 +27,7 @@ type mergeContext struct {
 	doer      *user_model.User
 	sig       *git.Signature
 	committer *git.Signature
-	signKeyID string // empty for no-sign, non-empty to sign
+	signKey   *git.SigningKey
 	env       []string
 }
 
@@ -99,9 +99,9 @@ func createTemporaryRepoForMerge(ctx context.Context, pr *issues_model.PullReque
 	mergeCtx.committer = mergeCtx.sig
 
 	// Determine if we should sign
-	sign, keyID, signer, _ := asymkey_service.SignMerge(ctx, mergeCtx.pr, mergeCtx.doer, mergeCtx.tmpBasePath, "HEAD", trackingBranch)
+	sign, key, signer, _ := asymkey_service.SignMerge(ctx, mergeCtx.pr, mergeCtx.doer, mergeCtx.tmpBasePath, "HEAD", trackingBranch)
 	if sign {
-		mergeCtx.signKeyID = keyID
+		mergeCtx.signKey = key
 		if pr.BaseRepo.GetTrustModel() == repo_model.CommitterTrustModel || pr.BaseRepo.GetTrustModel() == repo_model.CollaboratorCommitterTrustModel {
 			mergeCtx.committer = signer
 		}
diff --git a/services/pull/merge_squash.go b/services/pull/merge_squash.go
index 119b28736c..0049c0b117 100644
--- a/services/pull/merge_squash.go
+++ b/services/pull/merge_squash.go
@@ -71,10 +71,13 @@ func doMergeStyleSquash(ctx *mergeContext, message string) error {
 	cmdCommit := git.NewCommand("commit").
 		AddOptionFormat("--author='%s <%s>'", sig.Name, sig.Email).
 		AddOptionFormat("--message=%s", message)
-	if ctx.signKeyID == "" {
+	if ctx.signKey == nil {
 		cmdCommit.AddArguments("--no-gpg-sign")
 	} else {
-		cmdCommit.AddOptionFormat("-S%s", ctx.signKeyID)
+		if ctx.signKey.Format != "" {
+			cmdCommit.AddConfig("gpg.format", ctx.signKey.Format)
+		}
+		cmdCommit.AddOptionFormat("-S%s", ctx.signKey.KeyID)
 	}
 	if err := cmdCommit.Run(ctx, ctx.RunOpts()); err != nil {
 		log.Error("git commit %-v: %v\n%s\n%s", ctx.pr, err, ctx.outbuf.String(), ctx.errbuf.String())