Retry Docker readiness probes that time out with SIGPIPE

builder.mjs

@@ -37,7 +37,8 @@ export async function command(executable, args, env, timeout = 120_000) {
     return stdout;
   } catch (error) {
     // Never include argv, environment, or stdout (which may contain credentials).
-    const timedOut = error.killed && error.signal === 'SIGTERM' && error.code == null;
+    // A deadline kill can finish with SIGPIPE while Docker shuts down.
+    const timedOut = error.killed && error.code == null;
     const details = [timedOut ? `timed out after ${timeout / 1000}s` : 'command failed',
       `exit=${error.code ?? 'none'}`, `signal=${error.signal ?? 'none'}`, `killed=${Boolean(error.killed)}`];
     const operation = args.includes('version') ? 'version' : args.slice(0, 2).filter(a => /^[a-z-]+$/.test(a)).join(' ');

builder.test.mjs

@@ -484,3 +484,21 @@ test('installation and CLI calls follow the selected hosted API', async t => {
     assert.equal(f.calls.find(c => c.args[1] === 'status').env.VEX_API_BASE_URL, api);
   }
 });
+
+test('deadline kills remain retryable when the child shuts down with SIGPIPE', { skip: process.platform === 'win32' }, async () => {
+  await assert.rejects(command('/bin/sh', ['-c',
+    "trap 'kill -PIPE $$' TERM; while :; do sleep 0.05; done"],
+  {}, 300), error => {
+    assert.match(error.message, /timed out after 0.3s/);
+    assert.match(error.message, /signal=SIGPIPE, killed=true/);
+    return true;
+  });
+});
+
+test('a child exiting on SIGPIPE without a deadline kill is not reported as a timeout', { skip: process.platform === 'win32' }, async () => {
+  await assert.rejects(command('/bin/sh', ['-c', 'kill -PIPE $$'], {}), error => {
+    assert.match(error.message, /command failed/);
+    assert.doesNotMatch(error.message, /timed out/);
+    return true;
+  });
+});