fix: avoid storage probe redirect timeouts

scripts/migration-integrity-check-helpers.mjs

@@ -18,14 +18,33 @@ export function getMigrationStorageUrlConcurrency(env = process.env) {
 export async function checkStorageUrl(baseUrl, storageUrl, options = {}) {
   const timeoutMs = Number(options.timeoutMs || 10_000);
   const fetchImpl = options.fetchImpl || fetch;
+  const targetUrl = `${baseUrl}${storageUrl}`;
+
   try {
-    const response = await fetchImpl(`${baseUrl}${storageUrl}`, {
+    const response = await fetchImpl(targetUrl, {
+      method: 'HEAD',
+      redirect: 'manual',
       signal: AbortSignal.timeout(timeoutMs),
     });
     await response.body?.cancel?.();
-    if (!response.ok) {
+
+    if (isReachableStorageResponse(response)) {
+      return { ok: true };
+    }
+
+    if (response.status !== 405) {
       return { ok: false, error: `HTTP ${response.status}` };
     }
+
+    const fallback = await fetchImpl(targetUrl, {
+      redirect: 'manual',
+      signal: AbortSignal.timeout(timeoutMs),
+    });
+    await fallback.body?.cancel?.();
+    if (!isReachableStorageResponse(fallback)) {
+      return { ok: false, error: `HTTP ${fallback.status}` };
+    }
+
     return { ok: true };
   } catch (error) {
     return {
@@ -34,3 +53,10 @@ export async function checkStorageUrl(baseUrl, storageUrl, options = {}) {
     };
   }
 }
+
+function isReachableStorageResponse(response) {
+  if (response.ok) return true;
+  return response.status >= 300
+    && response.status < 400
+    && Boolean(response.headers?.get?.('location'));
+}

scripts/test-ops-hardening.mjs

@@ -71,6 +71,24 @@ await runTest('migration storage URL check records fetch failures instead of thr
   });
 });
 
+await runTest('migration storage URL check treats local-storage redirects as reachable', async () => {
+  const calls = [];
+  const result = await checkStorageUrl('http://127.0.0.1:8000', '/api/local-storage/gallery/images/work.png', {
+    timeoutMs: 10,
+    fetchImpl: async (_url, init) => {
+      calls.push(init);
+      return new Response(null, {
+        status: 302,
+        headers: { Location: 'https://object-storage.example/work.png' },
+      });
+    },
+  });
+
+  assert.deepEqual(result, { ok: true });
+  assert.equal(calls[0].method, 'HEAD');
+  assert.equal(calls[0].redirect, 'manual');
+});
+
 await runTest('migration integrity script uses resilient storage URL helpers', () => {
   const source = read('scripts/migration-integrity-check.mjs');