Modernize merge button (#28140)

- Make use of the `form-fetch-action` for the merge button, which will
automatically prevent the action from happening multiple times and show
a nice loading indicator as user feedback while the merge request is
being processed by the server.
- Adjust the merge PR code to JSON response as this is required for the
`form-fetch-action` functionality.
- Resolves https://codeberg.org/forgejo/forgejo/issues/774
- Likely resolves the cause of
https://codeberg.org/forgejo/forgejo/issues/1688#issuecomment-1313044

(cherry picked from commit 4ec64c19507caefff7ddaad722b1b5792b97cc5a)

Co-authored-by: Gusted <postmaster@gusted.xyz>

1 files changed, 21 insertions, 24 deletions

diff --git a/routers/web/repo/pull.go b/routers/web/repo/pull.go
index a7e703d01c..32d82b2a64 100644
--- a/routers/web/repo/pull.go
+++ b/routers/web/repo/pull.go
@@ -1149,30 +1149,28 @@ func MergePullRequest(ctx *context.Context) {
 		switch {
 		case errors.Is(err, pull_service.ErrIsClosed):
 			if issue.IsPull {
-				ctx.Flash.Error(ctx.Tr("repo.pulls.is_closed"))
+				ctx.JSONError(ctx.Tr("repo.pulls.is_closed"))
 			} else {
-				ctx.Flash.Error(ctx.Tr("repo.issues.closed_title"))
+				ctx.JSONError(ctx.Tr("repo.issues.closed_title"))
 			}
 		case errors.Is(err, pull_service.ErrUserNotAllowedToMerge):
-			ctx.Flash.Error(ctx.Tr("repo.pulls.update_not_allowed"))
+			ctx.JSONError(ctx.Tr("repo.pulls.update_not_allowed"))
 		case errors.Is(err, pull_service.ErrHasMerged):
-			ctx.Flash.Error(ctx.Tr("repo.pulls.has_merged"))
+			ctx.JSONError(ctx.Tr("repo.pulls.has_merged"))
 		case errors.Is(err, pull_service.ErrIsWorkInProgress):
-			ctx.Flash.Error(ctx.Tr("repo.pulls.no_merge_wip"))
+			ctx.JSONError(ctx.Tr("repo.pulls.no_merge_wip"))
 		case errors.Is(err, pull_service.ErrNotMergableState):
-			ctx.Flash.Error(ctx.Tr("repo.pulls.no_merge_not_ready"))
+			ctx.JSONError(ctx.Tr("repo.pulls.no_merge_not_ready"))
 		case models.IsErrDisallowedToMerge(err):
-			ctx.Flash.Error(ctx.Tr("repo.pulls.no_merge_not_ready"))
+			ctx.JSONError(ctx.Tr("repo.pulls.no_merge_not_ready"))
 		case asymkey_service.IsErrWontSign(err):
-			ctx.Flash.Error(err.Error()) // has no translation ...
+			ctx.JSONError(err.Error()) // has no translation ...
 		case errors.Is(err, pull_service.ErrDependenciesLeft):
-			ctx.Flash.Error(ctx.Tr("repo.issues.dependency.pr_close_blocked"))
+			ctx.JSONError(ctx.Tr("repo.issues.dependency.pr_close_blocked"))
 		default:
 			ctx.ServerError("WebCheck", err)
-			return
 		}
 
-		ctx.Redirect(issue.Link())
 		return
 	}
 
@@ -1180,18 +1178,18 @@ func MergePullRequest(ctx *context.Context) {
 	if manuallyMerged {
 		if err := pull_service.MergedManually(ctx, pr, ctx.Doer, ctx.Repo.GitRepo, form.MergeCommitID); err != nil {
 			switch {
-
 			case models.IsErrInvalidMergeStyle(err):
-				ctx.Flash.Error(ctx.Tr("repo.pulls.invalid_merge_option"))
+				ctx.JSONError(ctx.Tr("repo.pulls.invalid_merge_option"))
 			case strings.Contains(err.Error(), "Wrong commit ID"):
-				ctx.Flash.Error(ctx.Tr("repo.pulls.wrong_commit_id"))
+				ctx.JSONError(ctx.Tr("repo.pulls.wrong_commit_id"))
 			default:
 				ctx.ServerError("MergedManually", err)
-				return
 			}
+
+			return
 		}
 
-		ctx.Redirect(issue.Link())
+		ctx.JSONRedirect(issue.Link())
 		return
 	}
 
@@ -1221,15 +1219,14 @@ func MergePullRequest(ctx *context.Context) {
 		} else if scheduled {
 			// nothing more to do ...
 			ctx.Flash.Success(ctx.Tr("repo.pulls.auto_merge_newly_scheduled"))
-			ctx.Redirect(fmt.Sprintf("%s/pulls/%d", ctx.Repo.RepoLink, pr.Index))
+			ctx.JSONRedirect(fmt.Sprintf("%s/pulls/%d", ctx.Repo.RepoLink, pr.Index))
 			return
 		}
 	}
 
 	if err := pull_service.Merge(ctx, pr, ctx.Doer, ctx.Repo.GitRepo, repo_model.MergeStyle(form.Do), form.HeadCommitID, message, false); err != nil {
 		if models.IsErrInvalidMergeStyle(err) {
-			ctx.Flash.Error(ctx.Tr("repo.pulls.invalid_merge_option"))
-			ctx.Redirect(issue.Link())
+			ctx.JSONError(ctx.Tr("repo.pulls.invalid_merge_option"))
 		} else if models.IsErrMergeConflicts(err) {
 			conflictError := err.(models.ErrMergeConflicts)
 			flashError, err := ctx.RenderToString(tplAlertDetails, map[string]any{
@@ -1242,7 +1239,7 @@ func MergePullRequest(ctx *context.Context) {
 				return
 			}
 			ctx.Flash.Error(flashError)
-			ctx.Redirect(issue.Link())
+			ctx.JSONRedirect(issue.Link())
 		} else if models.IsErrRebaseConflicts(err) {
 			conflictError := err.(models.ErrRebaseConflicts)
 			flashError, err := ctx.RenderToString(tplAlertDetails, map[string]any{
@@ -1286,7 +1283,7 @@ func MergePullRequest(ctx *context.Context) {
 				}
 				ctx.Flash.Error(flashError)
 			}
-			ctx.Redirect(issue.Link())
+			ctx.JSONRedirect(issue.Link())
 		} else {
 			ctx.ServerError("Merge", err)
 		}
@@ -1295,7 +1292,7 @@ func MergePullRequest(ctx *context.Context) {
 	log.Trace("Pull request merged: %d", pr.ID)
 
 	if err := stopTimerIfAvailable(ctx, ctx.Doer, issue); err != nil {
-		ctx.ServerError("CreateOrStopIssueStopwatch", err)
+		ctx.ServerError("stopTimerIfAvailable", err)
 		return
 	}
 
@@ -1309,7 +1306,7 @@ func MergePullRequest(ctx *context.Context) {
 			return
 		}
 		if exist {
-			ctx.Redirect(issue.Link())
+			ctx.JSONRedirect(issue.Link())
 			return
 		}
 
@@ -1327,7 +1324,7 @@ func MergePullRequest(ctx *context.Context) {
 		deleteBranch(ctx, pr, headRepo)
 	}
 
-	ctx.Redirect(issue.Link())
+	ctx.JSONRedirect(issue.Link())
 }
 
 // CancelAutoMergePullRequest cancels a scheduled pr