fix(platform): check for a saved upload when a replay's 4xx body drops

After an unclear failure, the replay is rejected with a 4xx. If that
response body dropped, the deploy failed before the saved-upload check
ran. It now runs the same check first.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

Author: Brooooooklyn

platform/packages/api/src/deploy/upload-worker.ts

@@ -516,11 +516,6 @@ export async function uploadDeploymentWorker(input: {
         if (failure instanceof WorkerModuleIntegrityError) {
           throw failure;
         }
-        // A 4xx stays final even when its body drops. Any other failure is
-        // retried.
-        if (cfResponse && !cfResponse.ok && cfResponse.status < 500) {
-          throw new Error(`worker upload failed (HTTP ${cfResponse.status})`, { cause: error });
-        }
         const timedOut = (error as { name?: unknown } | null)?.name === 'TimeoutError';
         const cause = failure ?? error;
         const fields = {
@@ -531,6 +526,14 @@ export async function uploadDeploymentWorker(input: {
           status: cfResponse?.status,
           err: cause instanceof Error ? cause.message : String(cause),
         };
+        // A 4xx stays final even when its body drops, unless it replays an
+        // upload that was saved. Any other failure is retried.
+        if (cfResponse && !cfResponse.ok && cfResponse.status < 500) {
+          if (maybeSaved && (await savedDespiteFailure(fields))) {
+            return true;
+          }
+          throw new Error(`worker upload failed (HTTP ${cfResponse.status})`, { cause: error });
+        }
         if (lastAttempt) {
           // This attempt or an earlier one may have been saved.
           if (await savedDespiteFailure(fields)) {

platform/packages/api/test/integration/api-deploy.test.ts

@@ -2866,6 +2866,41 @@ describe('POST /projects/:id/deploy', () => {
       expect(dispatchScriptReads(cf)).toBe(1);
     });
 
+    it('treats an upload saved before a replay whose 4xx body drops as done', async () => {
+      const user = await createTestUser(env.db);
+      const project = await createTestProject(env.db, user.id, 'worker-upload-saved-4xx-body');
+      const savedLogs = captureSavedUploadLogs();
+      let uploadCalls = 0;
+      const cf: MockCfApiHandle = mockCfApi({
+        uploadWorker: async (url, init) => {
+          uploadCalls++;
+          if (uploadCalls === 1) {
+            await saveScript(cf, url, init);
+            throw new TypeError('fetch failed');
+          }
+          return brokenBodyResponse(400);
+        },
+      });
+
+      const res = await app.fetch(await buildDeployRequest(env, project.id, user.jwt), env);
+
+      expect(res.status).toBe(200);
+      const events = parseDeployStream(await res.text());
+      expect(events.at(-1)).toMatchObject({ event: 'done' });
+      expect(uploadCalls).toBe(2);
+      expect(dispatchScriptReads(cf)).toBe(1);
+      expect(savedLogs()).toEqual([
+        expect.objectContaining({
+          attempt: 1,
+          maxAttempts: 4,
+          latencyMs: expect.any(Number),
+          code: 'transport',
+          status: 400,
+          err: 'terminated',
+        }),
+      ]);
+    });
+
     it('treats an upload saved before the last attempt times out as done', async () => {
       const user = await createTestUser(env.db);
       const project = await createTestProject(env.db, user.id, 'worker-upload-saved-timeout');