fix reopen logic for agit flow pull request (#26399)

the head branch is meaningless for a agit flow pull request, so should
not check it when reopen it.

related: #24231
fix #26334

Signed-off-by: a1012112796 <1012112796@qq.com>

routers/web/repo/issue.go

@@ -2935,52 +2935,54 @@ func NewComment(ctx *context.Context) {
 
 				// check whether the ref of PR <refs/pulls/pr_index/head> in base repo is consistent with the head commit of head branch in the head repo
 				// get head commit of PR
-				prHeadRef := pull.GetGitRefName()
-				if err := pull.LoadBaseRepo(ctx); err != nil {
-					ctx.ServerError("Unable to load base repo", err)
-					return
-				}
-				prHeadCommitID, err := git.GetFullCommitID(ctx, pull.BaseRepo.RepoPath(), prHeadRef)
-				if err != nil {
-					ctx.ServerError("Get head commit Id of pr fail", err)
-					return
-				}
-
-				// get head commit of branch in the head repo
-				if err := pull.LoadHeadRepo(ctx); err != nil {
-					ctx.ServerError("Unable to load head repo", err)
-					return
-				}
-				if ok := git.IsBranchExist(ctx, pull.HeadRepo.RepoPath(), pull.BaseBranch); !ok {
-					// todo localize
-					ctx.JSONError("The origin branch is delete, cannot reopen.")
-					return
-				}
-				headBranchRef := pull.GetGitHeadBranchRefName()
-				headBranchCommitID, err := git.GetFullCommitID(ctx, pull.HeadRepo.RepoPath(), headBranchRef)
-				if err != nil {
-					ctx.ServerError("Get head commit Id of head branch fail", err)
-					return
-				}
+				if pull.Flow == issues_model.PullRequestFlowGithub {
+					prHeadRef := pull.GetGitRefName()
+					if err := pull.LoadBaseRepo(ctx); err != nil {
+						ctx.ServerError("Unable to load base repo", err)
+						return
+					}
+					prHeadCommitID, err := git.GetFullCommitID(ctx, pull.BaseRepo.RepoPath(), prHeadRef)
+					if err != nil {
+						ctx.ServerError("Get head commit Id of pr fail", err)
+						return
+					}
 
-				err = pull.LoadIssue(ctx)
-				if err != nil {
-					ctx.ServerError("load the issue of pull request error", err)
-					return
-				}
+					// get head commit of branch in the head repo
+					if err := pull.LoadHeadRepo(ctx); err != nil {
+						ctx.ServerError("Unable to load head repo", err)
+						return
+					}
+					if ok := git.IsBranchExist(ctx, pull.HeadRepo.RepoPath(), pull.BaseBranch); !ok {
+						// todo localize
+						ctx.JSONError("The origin branch is delete, cannot reopen.")
+						return
+					}
+					headBranchRef := pull.GetGitHeadBranchRefName()
+					headBranchCommitID, err := git.GetFullCommitID(ctx, pull.HeadRepo.RepoPath(), headBranchRef)
+					if err != nil {
+						ctx.ServerError("Get head commit Id of head branch fail", err)
+						return
+					}
 
-				if prHeadCommitID != headBranchCommitID {
-					// force push to base repo
-					err := git.Push(ctx, pull.HeadRepo.RepoPath(), git.PushOptions{
-						Remote: pull.BaseRepo.RepoPath(),
-						Branch: pull.HeadBranch + ":" + prHeadRef,
-						Force:  true,
-						Env:    repo_module.InternalPushingEnvironment(pull.Issue.Poster, pull.BaseRepo),
-					})
+					err = pull.LoadIssue(ctx)
 					if err != nil {
-						ctx.ServerError("force push error", err)
+						ctx.ServerError("load the issue of pull request error", err)
 						return
 					}
+
+					if prHeadCommitID != headBranchCommitID {
+						// force push to base repo
+						err := git.Push(ctx, pull.HeadRepo.RepoPath(), git.PushOptions{
+							Remote: pull.BaseRepo.RepoPath(),
+							Branch: pull.HeadBranch + ":" + prHeadRef,
+							Force:  true,
+							Env:    repo_module.InternalPushingEnvironment(pull.Issue.Poster, pull.BaseRepo),
+						})
+						if err != nil {
+							ctx.ServerError("force push error", err)
+							return
+						}
+					}
 				}
 			}