fix#5252, double click to submit pull request will make 2 same pr.

models/error.go

@@ -414,6 +414,20 @@ func (err ErrPullRequestNotExist) Error() string {
 		err.ID, err.IssueID, err.HeadRepoID, err.BaseRepoID, err.HeadBarcnh, err.BaseBranch)
 }
 
+type ErrPullRequestExist struct {
+	ID         int64
+	IssueID    int64
+	HeadRepoID int64
+	BaseRepoID int64
+	HeadBarcnh string
+	BaseBranch string
+}
+
+func (err ErrPullRequestExist) Error() string {
+	return fmt.Sprintf("pull request already exist [id: %d, issue_id: %d, head_repo_id: %d, base_repo_id: %d, head_branch: %s, base_branch: %s]",
+		err.ID, err.IssueID, err.HeadRepoID, err.BaseRepoID, err.HeadBarcnh, err.BaseBranch)
+}
+
 // _________                                       __
 // \_   ___ \  ____   _____   _____   ____   _____/  |_
 // /    \  \/ /  _ \ /     \ /     \_/ __ \ /    \   __\

models/pull.go

@@ -525,6 +525,20 @@ func GetUnmergedPullRequest(headRepoID, baseRepoID int64, headBranch, baseBranch
 	return pr, nil
 }
 
+// CheckPullRequestExist returns if the pull request has been create before create a new pull request
+func CheckPullRequestExist(headRepoID, baseRepoID int64, headBranch, baseBranch string) (bool, error) {
+	pr := new(PullRequest)
+	has, err := x.Where("head_repo_id=? AND head_branch=? AND base_repo_id=? AND base_branch=? AND has_merged=? AND issue.is_closed=?",
+		headRepoID, headBranch, baseRepoID, baseBranch, false, false).
+		Join("INNER", "issue", "issue.id=pull_request.issue_id").Get(pr)
+	if err != nil {
+		return false, err
+	} else if has {
+		return true, ErrPullRequestExist{pr.ID, pr.IssueID, headRepoID, baseRepoID, headBranch, baseBranch}
+	}
+	return false, nil
+}
+
 // GetUnmergedPullRequestsByHeadInfo returnss all pull requests that are open and has not been merged
 // by given head information (repo and branch).
 func GetUnmergedPullRequestsByHeadInfo(repoID int64, branch string) ([]*PullRequest, error) {

routes/repo/pull.go

@@ -655,6 +655,14 @@ func CompareAndPullRequestPost(c *context.Context, f form.NewIssue) {
 		return
 	}
 
+	// check one people send the pr at the same time
+	has , err := models.CheckPullRequestExist(headRepo.ID, c.Repo.Repository.ID, headBranch, baseBranch)
+
+	if has || err != nil {
+		c.ServerError("CheckPullRequestExist",err)
+		return
+	}
+
 	labelIDs, milestoneID, assigneeID := ValidateRepoMetas(c, f)
 	if c.Written() {
 		return