Fix possible pull request broken when leave the page immediately after clicking the update button (#34509) (#34607)

Backport #34509 by @lunny

If user leaves the page, the context will become cancelled, so that the
update process maybe terminal in an unexpected status. This PR haven't
resolve the problem totally. It uses a background context to not cancel
the update process even if the user leaved the pull request view page.

Fix #31779

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

routers/api/v1/repo/pull.go

@@ -23,6 +23,7 @@ import (
 	"code.gitea.io/gitea/modules/base"
 	"code.gitea.io/gitea/modules/git"
 	"code.gitea.io/gitea/modules/gitrepo"
+	"code.gitea.io/gitea/modules/graceful"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
 	api "code.gitea.io/gitea/modules/structs"
@@ -1301,7 +1302,7 @@ func UpdatePullRequest(ctx *context.APIContext) {
 	// default merge commit message
 	message := fmt.Sprintf("Merge branch '%s' into %s", pr.BaseBranch, pr.HeadBranch)
 
-	if err = pull_service.Update(ctx, pr, ctx.Doer, message, rebase); err != nil {
+	if err = pull_service.Update(graceful.GetManager().ShutdownContext(), pr, ctx.Doer, message, rebase); err != nil {
 		if pull_service.IsErrMergeConflicts(err) {
 			ctx.APIError(http.StatusConflict, "merge failed because of conflict")
 			return

routers/web/repo/pull.go

@@ -26,6 +26,7 @@ import (
 	"code.gitea.io/gitea/modules/emoji"
 	"code.gitea.io/gitea/modules/git"
 	"code.gitea.io/gitea/modules/gitrepo"
+	"code.gitea.io/gitea/modules/graceful"
 	issue_template "code.gitea.io/gitea/modules/issue/template"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
@@ -980,7 +981,9 @@ func UpdatePullRequest(ctx *context.Context) {
 	// default merge commit message
 	message := fmt.Sprintf("Merge branch '%s' into %s", issue.PullRequest.BaseBranch, issue.PullRequest.HeadBranch)
 
-	if err = pull_service.Update(ctx, issue.PullRequest, ctx.Doer, message, rebase); err != nil {
+	// The update process should not be cancelled by the user
+	// so we set the context to be a background context
+	if err = pull_service.Update(graceful.GetManager().ShutdownContext(), issue.PullRequest, ctx.Doer, message, rebase); err != nil {
 		if pull_service.IsErrMergeConflicts(err) {
 			conflictError := err.(pull_service.ErrMergeConflicts)
 			flashError, err := ctx.RenderToHTML(tplAlertDetails, map[string]any{

services/pull/update.go

@@ -41,22 +41,6 @@ func Update(ctx context.Context, pr *issues_model.PullRequest, doer *user_model.
 		return fmt.Errorf("HeadBranch of PR %d is up to date", pr.Index)
 	}
 
-	if rebase {
-		defer func() {
-			go AddTestPullRequestTask(TestPullRequestOptions{
-				RepoID:      pr.BaseRepo.ID,
-				Doer:        doer,
-				Branch:      pr.BaseBranch,
-				IsSync:      false,
-				IsForcePush: false,
-				OldCommitID: "",
-				NewCommitID: "",
-			})
-		}()
-
-		return updateHeadByRebaseOnToBase(ctx, pr, doer)
-	}
-
 	if err := pr.LoadBaseRepo(ctx); err != nil {
 		log.Error("unable to load BaseRepo for %-v during update-by-merge: %v", pr, err)
 		return fmt.Errorf("unable to load BaseRepo for PR[%d] during update-by-merge: %w", pr.ID, err)
@@ -74,6 +58,22 @@ func Update(ctx context.Context, pr *issues_model.PullRequest, doer *user_model.
 		return fmt.Errorf("unable to load HeadRepo for PR[%d] during update-by-merge: %w", pr.ID, err)
 	}
 
+	defer func() {
+		go AddTestPullRequestTask(TestPullRequestOptions{
+			RepoID:      pr.BaseRepo.ID,
+			Doer:        doer,
+			Branch:      pr.BaseBranch,
+			IsSync:      false,
+			IsForcePush: false,
+			OldCommitID: "",
+			NewCommitID: "",
+		})
+	}()
+
+	if rebase {
+		return updateHeadByRebaseOnToBase(ctx, pr, doer)
+	}
+
 	// TODO: FakePR: it is somewhat hacky, but it is the only way to "merge" at the moment
 	// ideally in the future the "merge" functions should be refactored to decouple from the PullRequest
 	// now use a fake reverse PR to switch head&base repos/branches
@@ -90,19 +90,6 @@ func Update(ctx context.Context, pr *issues_model.PullRequest, doer *user_model.
 	}
 
 	_, err = doMergeAndPush(ctx, reversePR, doer, repo_model.MergeStyleMerge, "", message, repository.PushTriggerPRUpdateWithBase)
-
-	defer func() {
-		go AddTestPullRequestTask(TestPullRequestOptions{
-			RepoID:      reversePR.HeadRepo.ID,
-			Doer:        doer,
-			Branch:      reversePR.HeadBranch,
-			IsSync:      false,
-			IsForcePush: false,
-			OldCommitID: "",
-			NewCommitID: "",
-		})
-	}()
-
 	return err
 }