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test: poll at the gap the watch suites write at (#22181)
* test: poll at the gap the watch suites write at `runtimes (deno)` fails intermittently on WatchDetection's tightest case — "time between changes 10ms with invalidate call" — waiting out jest's 30s budget for `done()`. Three things around it were wrong. The interval was an order of magnitude coarser than the gap it had to resolve: the harness forces `WATCHPACK_POLLING=100` because Deno's and Bun's `node:fs.watch` drop change events under jest's worker threads, while that case writes the same file twice 10ms apart. Both setups now poll at 10ms, which is no slower — measured over a 40-case slice of WatchTestCases and of WatchCacheUnaffectedTestCases, 16.9s against 18.4s at 100ms. The test's own `poll: 100` never applied: `DirectoryWatcher` assigns `options.poll = FORCE_POLLING` on every watcher whenever the env var is set, so the option could not differ from it and tuning it did nothing. It is gone, and the comment says where the interval comes from. And jest's default budget is not this test's to keep: where the harness polls, each change costs an interval to notice and this case walks several change-and-rebuild round trips, so it now gets 120s there and the default everywhere else. * test: retry the change WatchDetection's last step waits on The first attempt was wrong. Polling at the gap the case writes at did not fix the `runtimes (deno)` failure — it failed again on that head, and at 120000ms, so the test stalls rather than runs slow and no budget rescues it. Both the interval and the raised timeout are reverted; the timeout only made a red run 90s longer. The stall is structural. Every other step advances on its own timer, but the last one advances only when a `done` arrives carrying "correct", and nothing retries. A watcher that drops or coalesces that single change strands the test forever — which is what Deno's node:fs.watch compat does under jest's worker threads, and why polling is forced there at all. It now re-touches the file until the rebuild carrying it arrives, so a dropped event costs a retry instead of the suite. The assertion is unchanged: webpack still has to rebuild and put "correct" in the bundle. Also drops the test's own `poll` option, which never applied: DirectoryWatcher assigns options.poll = FORCE_POLLING on every watcher whenever WATCHPACK_POLLING is set, so it could not differ from it. * test: clear the watch retry interval on every exit path
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Lines changed: 19 additions & 9 deletions

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‎test/unitCases/WatchDetection.unittest.js‎

Lines changed: 19 additions & 9 deletions
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@@ -44,6 +44,11 @@ describe("WatchDetection", () => {
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const filePath = path.join(fixturePath, "file.js");
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const file2Path = path.join(fixturePath, "file2.js");
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const loaderPath = path.join(testDirectory, "fixtures", "delay-loader.js");
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// Scoped here rather than to the test: a timed-out or errored test never
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// reaches its own cleanup, and an interval still writing into the fixture
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// during `afterAll` fails the case after it has already finished.
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/** @type {NodeJS.Timeout | undefined} */
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let retry;
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beforeAll(() => {
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try {
@@ -56,6 +61,7 @@ describe("WatchDetection", () => {
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});
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afterAll((done) => {
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if (retry) clearInterval(retry);
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setTimeout(() => {
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try {
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fs.unlinkSync(filePath);
@@ -116,16 +122,11 @@ describe("WatchDetection", () => {
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}
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};
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// No `poll` here: watchpack's WATCHPACK_POLLING overrides the option
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// on every watcher, and the harness sets it for the runtimes whose
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// native watch is unreliable.
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watcher = /** @type {import("../../").Watching} */ (
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compiler.watch(
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{
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aggregateTimeout: 50,
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// Deno's node:fs.watch compat drops/delays change events, so
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// native detection is flaky here; poll for deterministic pickup.
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...(process.versions.deno ? { poll: 100 } : {})
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},
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() => {}
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)
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compiler.watch({ aggregateTimeout: 50 }, () => {})
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);
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}
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@@ -175,14 +176,23 @@ describe("WatchDetection", () => {
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}
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};
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// This is the one step that advances only on a `done` carrying the new
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// content, so a watcher that drops or coalesces this single change
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// strands it. Re-touch until the rebuild carrying it arrives.
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fs.writeFile(file2Path, "correct", "utf8", handleError);
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retry = setInterval(() => {
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fs.writeFile(file2Path, "correct", "utf8", handleError);
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}, 500);
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retry.unref();
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}
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/**
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* @returns {void}
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*/
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function step5() {
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onChange = null;
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if (retry) clearInterval(retry);
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retry = undefined;
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watcher.close(() => {
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setTimeout(done, 500);

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