fix: make "edit pr title & target branch" get correct branch (#39612)

* Fix #39610
* Regression of #39262

Also, the old code is very fragile: `#branch_target` is from translation
string, so refactored it together

---------

Co-authored-by: silverwind <me@silverwind.io>

templates/repo/issue/view_title.tmpl

@@ -103,7 +103,7 @@
 						{{svg "octicon-arrow-right"}}
 						<div class="ui floating dropdown" data-no-results="{{ctx.Locale.Tr "no_results_found"}}">
 							<div class="ui basic small button">
-								<span id="pull-target-branch" class="gt-ellipsis" data-base-user-name="{{$baseUserName}}" data-text-compare-base="{{ctx.Locale.Tr "repo.pulls.compare_base"}}">
+								<span id="pull-target-branch" class="gt-ellipsis" data-base-user-name="{{$baseUserName}}" data-old-target-branch="{{$baseBranch}}" data-branch="{{$baseBranch}}" data-text-compare-base="{{ctx.Locale.Tr "repo.pulls.compare_base"}}">
 									{{ctx.Locale.Tr "repo.pulls.compare_base"}}: {{$baseUserName}}:{{$baseBranch}}
 								</span>
 								{{svg "octicon-triangle-down" 14 "dropdown icon"}}

tests/e2e/pr-create.test.ts

@@ -1,8 +1,8 @@
 import {env} from 'node:process';
 import {test, expect} from '@playwright/test';
-import {login, apiCreateRepo, apiCreateFiles, randomString} from './utils.ts';
+import {login, apiCreateRepo, apiCreateFiles, apiCreatePR, randomString} from './utils.ts';
 
-test('create a pull request from the compare page', async ({page, request}) => {
+test('create a pull request from the compare page and edit its title', async ({page, request}) => {
   const repoName = `e2e-pr-create-${randomString(8)}`;
   const owner = env.GITEA_TEST_E2E_USER;
   await apiCreateRepo(request, {name: repoName});
@@ -17,7 +17,33 @@ test('create a pull request from the compare page', async ({page, request}) => {
   await page.getByPlaceholder('Title').fill(title);
   await page.getByRole('button', {name: 'Create Pull Request'}).click();
 
-  // commit, not full load: the PR title heading is server-rendered, so the assertion can resolve before the heavy diff/timeline finishes
+  await page.waitForURL(new RegExp(`/${owner}/${repoName}/pulls/\\d+$`), {waitUntil: 'domcontentloaded'});
-  await page.waitForURL(new RegExp(`/${owner}/${repoName}/pulls/\\d+$`), {waitUntil: 'commit'});
   await expect(page.getByRole('heading', {name: title})).toBeVisible();
+
+  const titleEditor = page.locator('#issue-title-editor');
+  await page.locator('#issue-title-display').getByRole('button', {name: 'Edit'}).click();
+  await titleEditor.getByRole('textbox').fill('edited title');
+  await titleEditor.getByRole('button', {name: 'Save'}).click();
+  await expect(page.getByRole('heading', {name: 'edited title'})).toBeVisible();
+});
+
+test('change the target branch of a pull request', async ({page, request}) => {
+  const repoName = `e2e-pr-target-${randomString(8)}`;
+  const owner = env.GITEA_TEST_E2E_USER;
+  const createPR = (async () => {
+    await apiCreateRepo(request, {name: repoName});
+    await Promise.all([
+      apiCreateFiles(request, owner, repoName, [{path: 'feat.txt', content: 'feature content\n'}], {branch: 'main', newBranch: 'feat'}),
+      apiCreateFiles(request, owner, repoName, [{path: 'release.txt', content: 'release content\n'}], {branch: 'main', newBranch: 'release'}),
+    ]);
+    return apiCreatePR(request, owner, repoName, 'feat', 'main', 'title');
+  })();
+  const [index] = await Promise.all([createPR, login(page)]);
+  await page.goto(`/${owner}/${repoName}/pulls/${index}`, {waitUntil: 'domcontentloaded'});
+
+  await page.locator('#issue-title-display').getByRole('button', {name: 'Edit'}).click();
+  await page.locator('#pull-target-branch').click();
+  await page.locator('#branch-select').getByText(`${owner}:release`).click();
+  await page.locator('#issue-title-editor').getByRole('button', {name: 'Save'}).click();
+  await expect(page.locator('#pull-desc-display')).toContainText('into release');
 });

web_src/js/features/repo-issue.ts

@@ -397,12 +397,13 @@ export function initRepoIssueTitleEdit() {
   });
 
   const pullDescEditor = document.querySelector('#pull-desc-editor'); // it may not exist for a merged PR
+  const pullTargetBranch = document.querySelector('#pull-target-branch');
   const prTargetUpdateUrl = pullDescEditor?.getAttribute('data-target-update-url');
 
   pullDescEditor?.querySelector('#branch-select')?.addEventListener('click', (e: Event) => {
     const el = (e.target as HTMLElement).closest('.item[data-branch]');
     if (!el) return;
-    const pullTargetBranch = pullDescEditor.querySelector('#pull-target-branch')!;
+    if (!pullTargetBranch) throw new Error('pullTargetBranch not found');
     const textCompareBase = pullTargetBranch.getAttribute('data-text-compare-base')!;
     const baseUserName = pullTargetBranch.getAttribute('data-base-user-name')!;
     const branchNameNew = el.getAttribute('data-branch')!;
@@ -422,8 +423,9 @@ export function initRepoIssueTitleEdit() {
         }
       }
       if (prTargetUpdateUrl) {
-        const newTargetBranch = document.querySelector('#pull-target-branch')!.getAttribute('data-branch');
+        if (!pullTargetBranch) throw new Error('pullTargetBranch not found');
-        const oldTargetBranch = document.querySelector('#branch_target')!.textContent;
+        const newTargetBranch = pullTargetBranch.getAttribute('data-branch');
+        const oldTargetBranch = pullTargetBranch.getAttribute('data-old-target-branch');
         if (newTargetBranch !== oldTargetBranch) {
           const resp = await POST(prTargetUpdateUrl, {data: new URLSearchParams({target_branch: String(newTargetBranch)})});
           if (!resp.ok) {