src: check mtime seconds for file-backed blobs

src/dataqueue/queue.cc

@@ -936,6 +936,7 @@ class FdEntry final : public EntryImpl {
 
   bool is_modified(const uv_stat_t& other) {
     return other.st_size != stat_.st_size ||
+           other.st_mtim.tv_sec != stat_.st_mtim.tv_sec ||
            other.st_mtim.tv_nsec != stat_.st_mtim.tv_nsec;
   }
 

test/parallel/test-blob-file-backed-mtime.js

@@ -0,0 +1,36 @@
+'use strict';
+
+require('../common');
+const assert = require('node:assert');
+const { test } = require('node:test');
+const {
+  openAsBlob,
+  openAsBlobSync,
+  statSync,
+  utimesSync,
+  writeFileSync,
+} = require('node:fs');
+const tmpdir = require('../common/tmpdir');
+
+tmpdir.refresh();
+
+for (const openBlob of [openAsBlob, openAsBlobSync]) {
+  test(`${openBlob.name} detects whole-second mtime changes`, async () => {
+    const file = tmpdir.resolve(openBlob.name);
+    const time = 1_700_000_000;
+    writeFileSync(file, 'before');
+    utimesSync(file, time, time);
+    const before = statSync(file, { bigint: true });
+
+    const blob = await openBlob(file);
+    assert.strictEqual(await blob.text(), 'before');
+
+    writeFileSync(file, 'after!');
+    utimesSync(file, time, time + 2);
+    const after = statSync(file, { bigint: true });
+    assert.strictEqual(after.size, before.size);
+    assert.strictEqual(after.mtimeNs - before.mtimeNs, 2_000_000_000n);
+
+    await assert.rejects(blob.text(), { name: 'NotReadableError' });
+  });
+}