Allow negotiated Docker readiness within the shared deadline

builder.mjs

@@ -205,11 +205,14 @@ export async function setup(env = process.env, run = command, wait = delay) {
   // the remote session. Retry this read only; never replay a build or push.
   // The control-plane wake is complete. Bound each native probe separately
   // so a stale connection cannot consume the entire readiness deadline.
+  // Docker negotiates its API with a ping before requesting the version. Each
+  // request establishes an authenticated tunnel; allow both to finish under
+  // load without restarting the shared 90-second readiness budget.
   const readinessDeadline = Date.now() + 90_000;
   for (let attempt = 0; attempt < 5; attempt++) {
     try {
       const version = await run('docker', ['--context', context, 'version', '--format', '{{.Server.Version}}'], dockerEnv,
-        Math.max(1, Math.min(15_000, readinessDeadline - Date.now())));
+        Math.max(1, Math.min(45_000, readinessDeadline - Date.now())));
       if (!/^\d+\.\d+\.\d+/.test(version.trim())) throw new Error('Remote Docker daemon is not ready');
       break;
     } catch (error) {

builder.test.mjs

@@ -371,7 +371,7 @@ test('a stalled native connection uses one readiness budget and cannot restart t
     return f.run(exe, args, env, timeout);
   };
   await assert.rejects(setup(f.env, run, async ms => waits.push(ms)), /connection reset/);
-  assert.deepEqual(timeouts, [15_000]);
+  assert.deepEqual(timeouts, [45_000]);
   assert.deepEqual(waits, []);
   await assert.rejects(readFile(f.env.GITHUB_OUTPUT), { code: 'ENOENT' });
 });
@@ -389,7 +389,7 @@ test('a long shared wake completes before opening short-lived Docker probes', as
     } });
     if (args.includes('version')) {
       assert.equal(now, 760_000);
-      assert.equal(timeout, 15_000);
+      assert.equal(timeout, 45_000);
     }
     return result;
   };
@@ -409,6 +409,28 @@ test('native probe timeouts are retried without repeating setup or a build', asy
   assert.equal(f.calls.filter(c => c.args[1] === 'setup').length, 1);
 });
 
+test('slow native negotiation can finish and retries share the remaining readiness budget', async t => {
+  const f = await fixture(t);
+  let now = 0;
+  t.mock.method(Date, 'now', () => now);
+  const timeouts = [];
+  const run = async (exe, args, env, timeout) => {
+    if (args.includes('version')) {
+      timeouts.push(timeout);
+      if (timeouts.length === 1) {
+        now += timeout;
+        throw new Error('timed out after 45s');
+      }
+      // A healthy negotiation may take longer than the former 15s limit.
+      now += 25_000;
+    }
+    return f.run(exe, args, env, timeout);
+  };
+  await setup(f.env, run, async ms => { now += ms; });
+  assert.deepEqual(timeouts, [45_000, 43_000]);
+  assert.ok((await readFile(f.env.GITHUB_OUTPUT, 'utf8')).includes('driver<<'));
+});
+
 test('command failures preserve timeout and signal details without stdout or environment', async () => {
   await assert.rejects(command(process.execPath, ['-e', "console.log('private-stdout'); setInterval(() => {}, 1000)"],
     { PRIVATE_TOKEN: 'private-env' }, 100), error => {