fix: render update download progress incrementally

Use the verified manifest size for percentage calculations, suppress duplicate percentage events, and yield between buffered download updates so Electron can paint intermediate progress before completion. Add a regression test that proves renderer-observable progress during an immediately buffered download.
2026-08-20 14:01:07 +02:00
parent 7074e6662d
commit 990d4c4ffa
2 changed files with 72 additions and 3 deletions
@@ -87,6 +87,71 @@ test('update preparation writes a verified installer without launching it', asyn
  }
 });

+test('buffered installer downloads yield between progress updates so the renderer can paint', async () => {
+  const tempDir = fs.mkdtempSync(path.join(os.tmpdir(), 'mhu-updater-progress-test-'));
+  const installer = Buffer.alloc(128 * 1024, 0);
+  installer[0] = 0x4d;
+  installer[1] = 0x5a;
+  const chunks = [
+    installer.subarray(0, 32 * 1024),
+    installer.subarray(32 * 1024, 64 * 1024),
+    installer.subarray(64 * 1024, 96 * 1024),
+    installer.subarray(96 * 1024)
+  ];
+  const progress = [];
+  let readerIndex = 0;
+  let preparationFinished = false;
+  let rendererObservedProgressBeforeFinish = false;
+  let rendererObservationScheduled = false;
+
+  try {
+    await prepareUpdate(value => {
+      progress.push(value);
+      if (value.stage !== 'downloading' || rendererObservationScheduled) return;
+      rendererObservationScheduled = true;
+      setImmediate(() => {
+        rendererObservedProgressBeforeFinish = !preparationFinished;
+      });
+    }, {
+      checkResult: {
+        available: true,
+        assetUrl: 'https://update.invalid/setup.exe',
+        assetName: 'setup.exe',
+        remoteVersion: '2.2.0',
+        latestYmlUrl: 'https://update.invalid/latest.yml'
+      },
+      tempDir,
+      fetchImpl: async url => url.endsWith('latest.yml')
+        ? {
+            ok: true,
+            status: 200,
+            text: async () => `version: 2.2.0\npath: setup.exe\nsha512: ${crypto.createHash('sha512').update(installer).digest('base64')}\nsize: ${installer.length}\n`
+          }
+        : {
+            ok: true,
+            status: 200,
+            body: {
+              getReader: () => ({
+                read: async () => readerIndex < chunks.length
+                  ? { done: false, value: chunks[readerIndex++] }
+                  : { done: true }
+              })
+            }
+          }
+    });
+    preparationFinished = true;
+    await new Promise(resolve => setImmediate(resolve));
+
+    assert.equal(rendererObservedProgressBeforeFinish, true);
+    assert.deepEqual(
+      progress.filter(value => value.stage === 'downloading').map(value => value.percent),
+      [25, 50, 75, 100]
+    );
+  } finally {
+    fs.rmSync(tempDir, { recursive: true, force: true });
+  }
+});
+
 test('update preparation refreshes a cached release before downloading the installer', async () => {
  const updaterPath = require.resolve('../lib/updater');
  const originalLoad = Module._load;