Start automerge check again after the conflict check and the schedule (go-gitea#35002)

Fix go-gitea#34988
Backport go-gitea#34989 

Co-authored-by: posativ

Co-authored-by: wxiaoguang <[email protected]>

Author: lunny

models/pull/automerge.go

@@ -5,12 +5,14 @@ package pull
 
 import (
 	"context"
+	"errors"
 	"fmt"
 
 	"code.gitea.io/gitea/models/db"
 	repo_model "code.gitea.io/gitea/models/repo"
 	user_model "code.gitea.io/gitea/models/user"
 	"code.gitea.io/gitea/modules/timeutil"
+	"code.gitea.io/gitea/modules/util"
 )
 
 // AutoMerge represents a pull request scheduled for merging when checks succeed
@@ -76,7 +78,10 @@ func GetScheduledMergeByPullID(ctx context.Context, pullID int64) (bool, *AutoMe
 		return false, nil, err
 	}
 
-	doer, err := user_model.GetUserByID(ctx, scheduledPRM.DoerID)
+	doer, err := user_model.GetPossibleUserByID(ctx, scheduledPRM.DoerID)
+	if errors.Is(err, util.ErrNotExist) {
+		doer, err = user_model.NewGhostUser(), nil
+	}
 	if err != nil {
 		return false, nil, err
 	}

services/automerge/automerge.go

@@ -22,23 +22,21 @@ import (
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/process"
 	"code.gitea.io/gitea/modules/queue"
+	"code.gitea.io/gitea/services/automergequeue"
 	notify_service "code.gitea.io/gitea/services/notify"
 	pull_service "code.gitea.io/gitea/services/pull"
 	repo_service "code.gitea.io/gitea/services/repository"
 )
 
-// prAutoMergeQueue represents a queue to handle update pull request tests
-var prAutoMergeQueue *queue.WorkerPoolQueue[string]
-
 // Init runs the task queue to that handles auto merges
 func Init() error {
 	notify_service.RegisterNotifier(NewNotifier())
 
-	prAutoMergeQueue = queue.CreateUniqueQueue(graceful.GetManager().ShutdownContext(), "pr_auto_merge", handler)
-	if prAutoMergeQueue == nil {
+	automergequeue.AutoMergeQueue = queue.CreateUniqueQueue(graceful.GetManager().ShutdownContext(), "pr_auto_merge", handler)
+	if automergequeue.AutoMergeQueue == nil {
 		return errors.New("unable to create pr_auto_merge queue")
 	}
-	go graceful.GetManager().RunWithCancel(prAutoMergeQueue)
+	go graceful.GetManager().RunWithCancel(automergequeue.AutoMergeQueue)
 	return nil
 }
 
@@ -56,24 +54,23 @@ func handler(items ...string) []string {
 	return nil
 }
 
-func addToQueue(pr *issues_model.PullRequest, sha string) {
-	log.Trace("Adding pullID: %d to the pull requests patch checking queue with sha %s", pr.ID, sha)
-	if err := prAutoMergeQueue.Push(fmt.Sprintf("%d_%s", pr.ID, sha)); err != nil {
-		log.Error("Error adding pullID: %d to the pull requests patch checking queue %v", pr.ID, err)
-	}
-}
-
 // ScheduleAutoMerge if schedule is false and no error, pull can be merged directly
 func ScheduleAutoMerge(ctx context.Context, doer *user_model.User, pull *issues_model.PullRequest, style repo_model.MergeStyle, message string, deleteBranchAfterMerge bool) (scheduled bool, err error) {
 	err = db.WithTx(ctx, func(ctx context.Context) error {
 		if err := pull_model.ScheduleAutoMerge(ctx, doer, pull.ID, style, message, deleteBranchAfterMerge); err != nil {
 			return err
 		}
-		scheduled = true
-
 		_, err = issues_model.CreateAutoMergeComment(ctx, issues_model.CommentTypePRScheduledToAutoMerge, pull, doer)
 		return err
 	})
+	// Old code made "scheduled" to be true after "ScheduleAutoMerge", but it's not right:
+	// If the transaction rolls back, then the pull request is not scheduled to auto merge.
+	// So we should only set "scheduled" to true if there is no error.
+	scheduled = err == nil
+	if scheduled {
+		log.Trace("Pull request [%d] scheduled for auto merge with style [%s] and message [%s]", pull.ID, style, message)
+		automergequeue.StartPRCheckAndAutoMerge(ctx, pull)
+	}
 	return scheduled, err
 }
 
@@ -99,38 +96,12 @@ func StartPRCheckAndAutoMergeBySHA(ctx context.Context, sha string, repo *repo_m
 	}
 
 	for _, pr := range pulls {
-		addToQueue(pr, sha)
+		automergequeue.AddToQueue(pr, sha)
 	}
 
 	return nil
 }
 
-// StartPRCheckAndAutoMerge start an automerge check and auto merge task for a pull request
-func StartPRCheckAndAutoMerge(ctx context.Context, pull *issues_model.PullRequest) {
-	if pull == nil || pull.HasMerged || !pull.CanAutoMerge() {
-		return
-	}
-
-	if err := pull.LoadBaseRepo(ctx); err != nil {
-		log.Error("LoadBaseRepo: %v", err)
-		return
-	}
-
-	gitRepo, err := gitrepo.OpenRepository(ctx, pull.BaseRepo)
-	if err != nil {
-		log.Error("OpenRepository: %v", err)
-		return
-	}
-	defer gitRepo.Close()
-	commitID, err := gitRepo.GetRefCommitID(pull.GetGitRefName())
-	if err != nil {
-		log.Error("GetRefCommitID: %v", err)
-		return
-	}
-
-	addToQueue(pull, commitID)
-}
-
 func getPullRequestsByHeadSHA(ctx context.Context, sha string, repo *repo_model.Repository, filter func(*issues_model.PullRequest) bool) (map[int64]*issues_model.PullRequest, error) {
 	gitRepo, err := gitrepo.OpenRepository(ctx, repo)
 	if err != nil {

services/automerge/notify.go

@@ -12,6 +12,7 @@ import (
 	user_model "code.gitea.io/gitea/models/user"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/repository"
+	"code.gitea.io/gitea/services/automergequeue"
 	notify_service "code.gitea.io/gitea/services/notify"
 )
 
@@ -45,7 +46,7 @@ func (n *automergeNotifier) PullReviewDismiss(ctx context.Context, doer *user_mo
 		return
 	}
 	// as reviews could have blocked a pending automerge let's recheck
-	StartPRCheckAndAutoMerge(ctx, review.Issue.PullRequest)
+	automergequeue.StartPRCheckAndAutoMerge(ctx, review.Issue.PullRequest)
 }
 
 func (n *automergeNotifier) CreateCommitStatus(ctx context.Context, repo *repo_model.Repository, commit *repository.PushCommit, sender *user_model.User, status *git_model.CommitStatus) {

services/automergequeue/automergequeue.go

@@ -0,0 +1,49 @@
+// Copyright 2025 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package automergequeue
+
+import (
+	"context"
+	"fmt"
+
+	issues_model "code.gitea.io/gitea/models/issues"
+	"code.gitea.io/gitea/modules/gitrepo"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/queue"
+)
+
+var AutoMergeQueue *queue.WorkerPoolQueue[string]
+
+var AddToQueue = func(pr *issues_model.PullRequest, sha string) {
+	log.Trace("Adding pullID: %d to the pull requests patch checking queue with sha %s", pr.ID, sha)
+	if err := AutoMergeQueue.Push(fmt.Sprintf("%d_%s", pr.ID, sha)); err != nil {
+		log.Error("Error adding pullID: %d to the pull requests patch checking queue %v", pr.ID, err)
+	}
+}
+
+// StartPRCheckAndAutoMerge start an automerge check and auto merge task for a pull request
+func StartPRCheckAndAutoMerge(ctx context.Context, pull *issues_model.PullRequest) {
+	if pull == nil || pull.HasMerged || !pull.CanAutoMerge() {
+		return
+	}
+
+	if err := pull.LoadBaseRepo(ctx); err != nil {
+		log.Error("LoadBaseRepo: %v", err)
+		return
+	}
+
+	gitRepo, err := gitrepo.OpenRepository(ctx, pull.BaseRepo)
+	if err != nil {
+		log.Error("OpenRepository: %v", err)
+		return
+	}
+	defer gitRepo.Close()
+	commitID, err := gitRepo.GetRefCommitID(pull.GetGitRefName())
+	if err != nil {
+		log.Error("GetRefCommitID: %v", err)
+		return
+	}
+
+	AddToQueue(pull, commitID)
+}

services/pull/check.go

@@ -1,5 +1,4 @@
-// Copyright 2019 The Gitea Authors.
-// All rights reserved.
+// Copyright 2019 The Gitea Authors. All rights reserved.
 // SPDX-License-Identifier: MIT
 
 package pull
@@ -16,6 +15,7 @@ import (
 	git_model "code.gitea.io/gitea/models/git"
 	issues_model "code.gitea.io/gitea/models/issues"
 	access_model "code.gitea.io/gitea/models/perm/access"
+	"code.gitea.io/gitea/models/pull"
 	repo_model "code.gitea.io/gitea/models/repo"
 	"code.gitea.io/gitea/models/unit"
 	user_model "code.gitea.io/gitea/models/user"
@@ -29,6 +29,7 @@ import (
 	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/modules/timeutil"
 	asymkey_service "code.gitea.io/gitea/services/asymkey"
+	"code.gitea.io/gitea/services/automergequeue"
 	notify_service "code.gitea.io/gitea/services/notify"
 )
 
@@ -238,7 +239,7 @@ func isSignedIfRequired(ctx context.Context, pr *issues_model.PullRequest, doer
 // markPullRequestAsMergeable checks if pull request is possible to leaving checking status,
 // and set to be either conflict or mergeable.
 func markPullRequestAsMergeable(ctx context.Context, pr *issues_model.PullRequest) {
-	// If status has not been changed to conflict by testPullRequestTmpRepoBranchMergeable then we are mergeable
+	// If the status has not been changed to conflict by testPullRequestTmpRepoBranchMergeable then we are mergeable
 	if pr.Status == issues_model.PullRequestStatusChecking {
 		pr.Status = issues_model.PullRequestStatusMergeable
 	}
@@ -257,6 +258,16 @@ func markPullRequestAsMergeable(ctx context.Context, pr *issues_model.PullReques
 	if err := pr.UpdateColsIfNotMerged(ctx, "merge_base", "status", "conflicted_files", "changed_protected_files"); err != nil {
 		log.Error("Update[%-v]: %v", pr, err)
 	}
+
+	// if there is a scheduled merge for this pull request, start the auto merge check (again)
+	exist, _, err := pull.GetScheduledMergeByPullID(ctx, pr.ID)
+	if err != nil {
+		log.Error("GetScheduledMergeByPullID[%-v]: %v", pr, err)
+		return
+	} else if !exist {
+		return
+	}
+	automergequeue.StartPRCheckAndAutoMerge(ctx, pr)
 }
 
 // getMergeCommit checks if a pull request has been merged

services/pull/check_test.go

@@ -1,5 +1,4 @@
-// Copyright 2019 The Gitea Authors.
-// All rights reserved.
+// Copyright 2019 The Gitea Authors. All rights reserved.
 // SPDX-License-Identifier: MIT
 
 package pull
@@ -11,11 +10,18 @@ import (
 
 	"code.gitea.io/gitea/models/db"
 	issues_model "code.gitea.io/gitea/models/issues"
+	"code.gitea.io/gitea/models/pull"
+	repo_model "code.gitea.io/gitea/models/repo"
 	"code.gitea.io/gitea/models/unittest"
+	user_model "code.gitea.io/gitea/models/user"
+	"code.gitea.io/gitea/modules/graceful"
 	"code.gitea.io/gitea/modules/queue"
 	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/test"
+	"code.gitea.io/gitea/services/automergequeue"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestPullRequest_AddToTaskQueue(t *testing.T) {
@@ -63,6 +69,46 @@ func TestPullRequest_AddToTaskQueue(t *testing.T) {
 	pr = unittest.AssertExistsAndLoadBean(t, &issues_model.PullRequest{ID: 2})
 	assert.Equal(t, issues_model.PullRequestStatusChecking, pr.Status)
 
-	prPatchCheckerQueue.ShutdownWait(5 * time.Second)
+	prPatchCheckerQueue.ShutdownWait(time.Second)
 	prPatchCheckerQueue = nil
 }
+
+func TestMarkPullRequestAsMergeable(t *testing.T) {
+	assert.NoError(t, unittest.PrepareTestDatabase())
+
+	prPatchCheckerQueue = queue.CreateUniqueQueue(graceful.GetManager().ShutdownContext(), "pr_patch_checker", func(items ...string) []string { return nil })
+	go prPatchCheckerQueue.Run()
+	defer func() {
+		prPatchCheckerQueue.ShutdownWait(time.Second)
+		prPatchCheckerQueue = nil
+	}()
+
+	addToQueueShaChan := make(chan string, 1)
+	defer test.MockVariableValue(&automergequeue.AddToQueue, func(pr *issues_model.PullRequest, sha string) {
+		addToQueueShaChan <- sha
+	})()
+	ctx := t.Context()
+	_, _ = db.GetEngine(ctx).ID(2).Update(&issues_model.PullRequest{Status: issues_model.PullRequestStatusChecking})
+	pr := unittest.AssertExistsAndLoadBean(t, &issues_model.PullRequest{ID: 2})
+	require.False(t, pr.HasMerged)
+	require.Equal(t, issues_model.PullRequestStatusChecking, pr.Status)
+
+	err := pull.ScheduleAutoMerge(ctx, &user_model.User{ID: 99999}, pr.ID, repo_model.MergeStyleMerge, "test msg", true)
+	require.NoError(t, err)
+
+	exist, scheduleMerge, err := pull.GetScheduledMergeByPullID(ctx, pr.ID)
+	require.NoError(t, err)
+	assert.True(t, exist)
+	assert.True(t, scheduleMerge.Doer.IsGhost())
+
+	markPullRequestAsMergeable(ctx, pr)
+	pr = unittest.AssertExistsAndLoadBean(t, &issues_model.PullRequest{ID: 2})
+	require.Equal(t, issues_model.PullRequestStatusMergeable, pr.Status)
+
+	select {
+	case sha := <-addToQueueShaChan:
+		assert.Equal(t, "985f0301dba5e7b34be866819cd15ad3d8f508ee", sha) // ref: refs/pull/3/head
+	case <-time.After(1 * time.Second):
+		assert.FailNow(t, "Timeout: nothing was added to automergequeue")
+	}
+}