feat: prepare conflict-safe release rollback pulls (Closes #1370)

tests/e2e/test_mobile_release_failure_recovery.py

@@ -89,3 +89,47 @@ def test_failed_release_check_is_diagnosable_and_retryable_on_phone(viewport):
         assert result["state"] == "Checks running"
         assert [call["method"] for call in result["calls"]] == ["GET", "GET", "POST"]
         browser.close()
+
+
+@pytest.mark.parametrize("viewport", [
+    {"width": 320, "height": 568},
+    {"width": 390, "height": 844},
+])
+def test_failed_release_prepares_a_visible_draft_rollback_receipt_on_phone(viewport):
+    with sync_playwright() as playwright:
+        browser = playwright.chromium.launch(headless=True)
+        page = browser.new_page(viewport=viewport)
+        page.set_content((FRONTEND / "index.html").read_text())
+        page.add_style_tag(path=FRONTEND / "dashboard.css")
+        page.add_script_tag(path=FRONTEND / "release-receipt.js")
+        result = page.evaluate("""async () => {
+          const values=new Map(), calls=[], opened=[];
+          const receipt=createReleaseReceipt({
+            storage:{getItem:key=>values.get(key)||null,setItem:(key,value)=>values.set(key,value),removeItem:key=>values.delete(key)},
+            getLogin:()=> 'timmy', listNode:document.querySelector('#release-watchlist'),
+            confirmAction:()=>true, openPull:pull=>opened.push(pull),
+            fetchJson:async(path, options={})=>{
+              calls.push({path,method:options.method||'GET'});
+              if(path.endsWith('/failure')) return {commit_sha:'abc1234',run_id:91,job_index:3,name:'CI / browser',excerpt:'failed'};
+              if(path.endsWith('/rollback')) return {repository:'stackchain/api',number:9,draft:true,rollback_of:'abc1234',url:'https://forge.example/git/stackchain/api/pulls/9'};
+              return {commit_sha:'abc1234',ci_state:'failure',release:null,checks:[{name:'CI / browser',state:'failure',recovery:{run_id:91,job_index:3}}]};
+            },
+          });
+          receipt.capture({repository:'stackchain/api',number:7,key:'stackchain/api#7'},{merge_commit_sha:'abc1234'});
+          document.querySelector('#release-receipt-sheet').showModal();
+          await receipt.refresh();
+          document.querySelector('.release-failure-summary button').click();
+          await new Promise(resolve=>setTimeout(resolve,0));
+          const rollback=[...document.querySelectorAll('.release-failure-actions button')].find(button=>button.textContent==='Prepare rollback PR');
+          const actionHeight=rollback.getBoundingClientRect().height;
+          rollback.click();
+          await new Promise(resolve=>setTimeout(resolve,0));
+          const status=document.querySelector('.release-rollback-status');
+          return {calls,opened,actionHeight,status:status?.textContent||'',overflow:document.documentElement.scrollWidth>document.documentElement.clientWidth};
+        }""")
+        assert result["actionHeight"] >= 44
+        assert result["status"] == "Draft rollback #9 is ready for review."
+        assert result["opened"][0]["number"] == 9
+        assert result["calls"][-1]["path"].endswith("/release-receipt/abc1234/rollback")
+        assert result["overflow"] is False
+        browser.close()