Fix commit retrieval by tag (#21804)

It is not correct to return tag data when commit data is requested, so
remove the hacky code that overwrote parts of a commit with parts of a
tag.

This fixes commit retrieval by tag for both the latest commit in the UI
and the commit info on tag webhook events.

Fixes: https://github.com/go-gitea/gitea/issues/21687
Replaces: https://github.com/go-gitea/gitea/pull/21693

<img width="324" alt="Screenshot 2022-11-13 at 15 26 37"
src="https://user-images.githubusercontent.com/115237/201526975-736c6ea7-ad6a-467a-a823-9a63d6ecb718.png">

<img width="789" alt="image"
src="https://user-images.githubusercontent.com/115237/201526876-90a13ffc-1e5c-4d76-911b-f1ae51e8eaab.png">

---------

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

1 files changed, 0 insertions, 39 deletions

diff --git a/modules/git/repo_commit_gogit.go b/modules/git/repo_commit_gogit.go
index 72de158e6e..ce0af93614 100644
--- a/modules/git/repo_commit_gogit.go
+++ b/modules/git/repo_commit_gogit.go
@@ -7,7 +7,6 @@
 package git
 
 import (
-	"fmt"
 	"strings"
 
 	"github.com/go-git/go-git/v5/plumbing"
@@ -67,38 +66,6 @@ func (repo *Repository) IsCommitExist(name string) bool {
 	return err == nil
 }
 
-func convertPGPSignatureForTag(t *object.Tag) *CommitGPGSignature {
-	if t.PGPSignature == "" {
-		return nil
-	}
-
-	var w strings.Builder
-	var err error
-
-	if _, err = fmt.Fprintf(&w,
-		"object %s\ntype %s\ntag %s\ntagger ",
-		t.Target.String(), t.TargetType.Bytes(), t.Name); err != nil {
-		return nil
-	}
-
-	if err = t.Tagger.Encode(&w); err != nil {
-		return nil
-	}
-
-	if _, err = fmt.Fprintf(&w, "\n\n"); err != nil {
-		return nil
-	}
-
-	if _, err = fmt.Fprintf(&w, t.Message); err != nil {
-		return nil
-	}
-
-	return &CommitGPGSignature{
-		Signature: t.PGPSignature,
-		Payload:   strings.TrimSpace(w.String()) + "\n",
-	}
-}
-
 func (repo *Repository) getCommit(id SHA1) (*Commit, error) {
 	var tagObject *object.Tag
 
@@ -122,12 +89,6 @@ func (repo *Repository) getCommit(id SHA1) (*Commit, error) {
 	commit := convertCommit(gogitCommit)
 	commit.repo = repo
 
-	if tagObject != nil {
-		commit.CommitMessage = strings.TrimSpace(tagObject.Message)
-		commit.Author = &tagObject.Tagger
-		commit.Signature = convertPGPSignatureForTag(tagObject)
-	}
-
 	tree, err := gogitCommit.Tree()
 	if err != nil {
 		return nil, err