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https://github.com/Microsoft/vscode
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a0b548807a
This adds an `assertHeap` function that can be used in tests. It takes a heap snapshot, and asserts the state of classes in memory. This works in Node and the Electron sandbox, but is a no-op in the browser. Snapshots are process asynchronously and will report failures at the end of the suite. This method should be used sparingly (e.g. once at the end of a suite to ensure nothing leaked before), as gathering a heap snapshot is fairly slow, at least until V8 11.5.130 (https://v8.dev/blog/speeding-up-v8-heap-snapshots). When used, the function will ensure the test has a minimum timeout duration of 20s to avoid immediate failures. It takes options containing a mapping of class names, and assertion functions to run on the number of retained instances of that class. For example: ```ts assertSnapshot({ classes: { ShouldNeverLeak: count => assert.strictEqual(count, 0), SomeSingleton: count => assert(count <= 1), } }); ``` Closes https://github.com/microsoft/vscode/issues/191920
86 lines
2.4 KiB
JavaScript
86 lines
2.4 KiB
JavaScript
/*---------------------------------------------------------------------------------------------
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* Copyright (c) Microsoft Corporation. All rights reserved.
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* Licensed under the MIT License. See License.txt in the project root for license information.
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*--------------------------------------------------------------------------------------------*/
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//@ts-check
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// note: we use a fork here since we can't make a worker from the renderer process
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const { fork } = require('child_process');
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const workerData = process.env.SNAPSHOT_WORKER_DATA;
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const fs = require('fs');
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const { pathToFileURL } = require('url');
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if (!workerData) {
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const { join } = require('path');
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const { tmpdir } = require('os');
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exports.takeSnapshotAndCountClasses = async (/** @type string */currentTest, /** @type string[] */ classes) => {
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const cleanTitle = currentTest.replace(/[^\w]+/g, '-');
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const file = join(tmpdir(), `vscode-test-snap-${cleanTitle}.heapsnapshot`);
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if (typeof process.takeHeapSnapshot !== 'function') {
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// node.js:
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const inspector = require('inspector');
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const session = new inspector.Session();
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session.connect();
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const fd = fs.openSync(file, 'w');
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await new Promise((resolve, reject) => {
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session.on('HeapProfiler.addHeapSnapshotChunk', (m) => {
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fs.writeSync(fd, m.params.chunk);
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});
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session.post('HeapProfiler.takeHeapSnapshot', null, (err) => {
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session.disconnect();
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fs.closeSync(fd);
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if (err) {
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reject(err);
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} else {
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resolve();
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}
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});
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});
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} else {
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// electron exposes this nice method for us:
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process.takeHeapSnapshot(file);
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}
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const worker = fork(__filename, {
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env: {
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...process.env,
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SNAPSHOT_WORKER_DATA: JSON.stringify({
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path: file,
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classes,
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})
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}
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});
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const promise = new Promise((resolve, reject) => {
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worker.on('message', (/** @type any */msg) => {
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if ('err' in msg) {
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reject(new Error(msg.err));
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} else {
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resolve(msg.counts);
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}
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worker.kill();
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});
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});
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return { done: promise, file: pathToFileURL(file) };
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};
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} else {
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const { path, classes } = JSON.parse(workerData);
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const { decode_bytes } = require('@vscode/v8-heap-parser');
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fs.promises.readFile(path)
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.then(buf => decode_bytes(buf))
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.then(graph => graph.get_class_counts(classes))
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.then(
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counts => process.send({ counts: Array.from(counts) }),
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err => process.send({ err: String(err.stack || err) })
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);
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}
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