fix incorrect role labels for migrated issues and comments (#22914)

Fix #22797.

## Reason
If a comment was migrated from other platforms, this comment may have an
original author and its poster is always not the original author. When
the `roleDescriptor` func get the poster's role descriptor for a
comment, it does not check if the comment has an original author. So the
migrated comments' original authors might be marked as incorrect roles.

---------

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

models/issues/comment.go

@@ -1244,3 +1244,8 @@ func FixCommentTypeLabelWithOutsideLabels(ctx context.Context) (int64, error) {
 
 	return res.RowsAffected()
 }
+
+// HasOriginalAuthor returns if a comment was migrated and has an original author.
+func (c *Comment) HasOriginalAuthor() bool {
+	return c.OriginalAuthor != "" && c.OriginalAuthorID != 0
+}

models/issues/issue.go

@@ -2403,3 +2403,8 @@ func DeleteOrphanedIssues(ctx context.Context) error {
 	}
 	return nil
 }
+
+// HasOriginalAuthor returns if an issue was migrated and has an original author.
+func (issue *Issue) HasOriginalAuthor() bool {
+	return issue.OriginalAuthor != "" && issue.OriginalAuthorID != 0
+}

routers/web/repo/issue.go

@@ -1142,7 +1142,11 @@ func NewIssuePost(ctx *context.Context) {
 }
 
 // roleDescriptor returns the Role Descriptor for a comment in/with the given repo, poster and issue
-func roleDescriptor(ctx stdCtx.Context, repo *repo_model.Repository, poster *user_model.User, issue *issues_model.Issue) (issues_model.RoleDescriptor, error) {
+func roleDescriptor(ctx stdCtx.Context, repo *repo_model.Repository, poster *user_model.User, issue *issues_model.Issue, hasOriginalAuthor bool) (issues_model.RoleDescriptor, error) {
+	if hasOriginalAuthor {
+		return issues_model.RoleDescriptorNone, nil
+	}
+
 	perm, err := access_model.GetUserRepoPermission(ctx, repo, poster)
 	if err != nil {
 		return issues_model.RoleDescriptorNone, err
@@ -1444,7 +1448,7 @@ func ViewIssue(ctx *context.Context) {
 	// check if dependencies can be created across repositories
 	ctx.Data["AllowCrossRepositoryDependencies"] = setting.Service.AllowCrossRepositoryDependencies
 
-	if issue.ShowRole, err = roleDescriptor(ctx, repo, issue.Poster, issue); err != nil {
+	if issue.ShowRole, err = roleDescriptor(ctx, repo, issue.Poster, issue, issue.HasOriginalAuthor()); err != nil {
 		ctx.ServerError("roleDescriptor", err)
 		return
 	}
@@ -1483,7 +1487,7 @@ func ViewIssue(ctx *context.Context) {
 				continue
 			}
 
-			comment.ShowRole, err = roleDescriptor(ctx, repo, comment.Poster, issue)
+			comment.ShowRole, err = roleDescriptor(ctx, repo, comment.Poster, issue, comment.HasOriginalAuthor())
 			if err != nil {
 				ctx.ServerError("roleDescriptor", err)
 				return
@@ -1582,7 +1586,7 @@ func ViewIssue(ctx *context.Context) {
 							continue
 						}
 
-						c.ShowRole, err = roleDescriptor(ctx, repo, c.Poster, issue)
+						c.ShowRole, err = roleDescriptor(ctx, repo, c.Poster, issue, c.HasOriginalAuthor())
 						if err != nil {
 							ctx.ServerError("roleDescriptor", err)
 							return