Add force_merge to merge request and fix checking mergable (#23010)

Fix #23000.

3 files changed, 30 insertions, 11 deletions

diff --git a/services/automerge/automerge.go b/services/automerge/automerge.go
index 74cfb8da8..994604764 100644
--- a/services/automerge/automerge.go
+++ b/services/automerge/automerge.go
@@ -230,7 +230,7 @@ func handlePull(pullID int64, sha string) {
 		return
 	}
 
-	if err := pull_service.CheckPullMergable(ctx, doer, &perm, pr, false, false); err != nil {
+	if err := pull_service.CheckPullMergable(ctx, doer, &perm, pr, pull_service.MergeCheckTypeGeneral, false); err != nil {
 		if errors.Is(pull_service.ErrUserNotAllowedToMerge, err) {
 			log.Info("%-v was scheduled to automerge by an unauthorized user", pr)
 			return
diff --git a/services/forms/repo_form.go b/services/forms/repo_form.go
index 374ae0ac5..e9645b5ab 100644
--- a/services/forms/repo_form.go
+++ b/services/forms/repo_form.go
@@ -604,7 +604,7 @@ type MergePullRequestForm struct {
 	MergeMessageField      string
 	MergeCommitID          string // only used for manually-merged
 	HeadCommitID           string `json:"head_commit_id,omitempty"`
-	ForceMerge             *bool  `json:"force_merge,omitempty"`
+	ForceMerge             bool   `json:"force_merge,omitempty"`
 	MergeWhenChecksSucceed bool   `json:"merge_when_checks_succeed,omitempty"`
 	DeleteBranchAfterMerge bool   `json:"delete_branch_after_merge,omitempty"`
 }
diff --git a/services/pull/check.go b/services/pull/check.go
index 310ea2e71..02d901541 100644
--- a/services/pull/check.go
+++ b/services/pull/check.go
@@ -59,8 +59,16 @@ func AddToTaskQueue(pr *issues_model.PullRequest) {
 	}
 }
 
+type MergeCheckType int
+
+const (
+	MergeCheckTypeGeneral  MergeCheckType = iota // general merge checks for "merge", "rebase", "squash", etc
+	MergeCheckTypeManually                       // Manually Merged button (mark a PR as merged manually)
+	MergeCheckTypeAuto                           // Auto Merge (Scheduled Merge) After Checks Succeed
+)
+
 // CheckPullMergable check if the pull mergable based on all conditions (branch protection, merge options, ...)
-func CheckPullMergable(stdCtx context.Context, doer *user_model.User, perm *access_model.Permission, pr *issues_model.PullRequest, manuallMerge, force bool) error {
+func CheckPullMergable(stdCtx context.Context, doer *user_model.User, perm *access_model.Permission, pr *issues_model.PullRequest, mergeCheckType MergeCheckType, adminSkipProtectionCheck bool) error {
 	return db.WithTx(stdCtx, func(ctx context.Context) error {
 		if pr.HasMerged {
 			return ErrHasMerged
@@ -80,8 +88,8 @@ func CheckPullMergable(stdCtx context.Context, doer *user_model.User, perm *acce
 			return ErrUserNotAllowedToMerge
 		}
 
-		if manuallMerge {
-			// don't check rules to "auto merge", doer is going to mark this pull as merged manually
+		if mergeCheckType == MergeCheckTypeManually {
+			// if doer is doing "manually merge" (mark as merged manually), do not check anything
 			return nil
 		}
 
@@ -103,14 +111,25 @@ func CheckPullMergable(stdCtx context.Context, doer *user_model.User, perm *acce
 				return err
 			}
 
-			if !force {
-				return err
+			// Now the branch protection check failed, check whether the failure could be skipped (skip by setting err = nil)
+
+			// * when doing Auto Merge (Scheduled Merge After Checks Succeed), skip the branch protection check
+			if mergeCheckType == MergeCheckTypeAuto {
+				err = nil
+			}
+
+			// * if the doer is admin, they could skip the branch protection check
+			if adminSkipProtectionCheck {
+				if isRepoAdmin, errCheckAdmin := access_model.IsUserRepoAdmin(ctx, pr.BaseRepo, doer); errCheckAdmin != nil {
+					log.Error("Unable to check if %-v is a repo admin in %-v: %v", doer, pr.BaseRepo, errCheckAdmin)
+					return errCheckAdmin
+				} else if isRepoAdmin {
+					err = nil // repo admin can skip the check, so clear the error
+				}
 			}
 
-			if isRepoAdmin, err2 := access_model.IsUserRepoAdmin(ctx, pr.BaseRepo, doer); err2 != nil {
-				log.Error("Unable to check if %-v is a repo admin in %-v: %v", doer, pr.BaseRepo, err2)
-				return err2
-			} else if !isRepoAdmin {
+			// If there is still a branch protection check error, return it
+			if err != nil {
 				return err
 			}
 		}