Merging pull request causes 500 error.

[PershingSquare]

• Gitea version (or commit ref): 1.10.0+dev-67-ge0d6d2f97
• Git version: 2.7.4, Git LFS 2.7.2
• Operating system: Alpine Linux v3.10
• Database (use [x]):
  • PostgreSQL
  • MySQL
  • MSSQL
  • SQLite
• Can you reproduce the bug at https://try.gitea.io:
  • Yes (provide example URL)
  • No, our repo use git-lfs and I wasn't able to reproduce it on there.
  • Not relevant
• Log gist:
  https://gist.github.com/PershingSquare/68118d48e13a082a749870cfa3a5e7cc

Description

Every time I try to merge a pull request, I get a 500 server error. I have branch protection on master, with 1 approval required before merging.

Screenshots

[zeripath]

OK so looking at the gitea.log you've sent it appears that the panic is being caused at line 104 here:

gitea/models/branches.go

Lines 102 to 108 in 734aa96

	// GetGrantedApprovalsCount returns the number of granted approvals for pr. A granted approval must be authored by a user in an approval whitelist.
	func (protectBranch *ProtectedBranch) GetGrantedApprovalsCount(pr *PullRequest) int64 {
	reviews, err := GetReviewersByPullID(pr.Issue.ID)
	if err != nil {
	log.Error("GetReviewersByPullID: %v", err)
	return 0
	}

This is in turn called from:

gitea/models/branches.go

Lines 94 to 100 in 734aa96

	// HasEnoughApprovals returns true if pr has enough granted approvals.
	func (protectBranch *ProtectedBranch) HasEnoughApprovals(pr *PullRequest) bool {
	if protectBranch.RequiredApprovals == 0 {
	return true
	}
	return protectBranch.GetGrantedApprovalsCount(pr) >= protectBranch.RequiredApprovals
	}

Which is from line 99 here:

gitea/routers/private/hook.go

Lines 89 to 105 in 734aa96

	canPush := protectBranch.CanUserPush(userID)
	if !canPush && prID > 0 {
	pr, err := models.GetPullRequestByID(prID)
	if err != nil {
	log.Error("Unable to get PullRequest %d Error: %v", prID, err)
	ctx.JSON(http.StatusInternalServerError, map[string]interface{}{
	"err": fmt.Sprintf("Unable to get PullRequest %d Error: %v", prID, err),
	})
	return
	}
	if !protectBranch.HasEnoughApprovals(pr) {
	log.Warn("Forbidden: User %d cannot push to protected branch: %s in %-v and pr #%d does not have enough approvals", userID, branchName, repo, pr.Index)
	ctx.JSON(http.StatusForbidden, map[string]interface{}{
	"err": fmt.Sprintf("protected branch %s can not be pushed to and pr #%d does not have enough approvals", branchName, prID),
	})
	return
	}

[zeripath]

Now that means that either pr is nil here, or pr.Issue is nil.

[zeripath]

OK, simple fix is to change pr.Issue.ID to pr.IssueID. However, when merging it shouldn't be pushing all of the branches so I'll look at that too.