Description
Possible duplicate of #3113.
I'm using using eslint-plugin-import v2.31.0 and eslint v8.57.1.
I've got a large work project that I'm attempting to migrate from a legacy-style config to a flat config in preparation for an eventual eslint 9 update. Unfortunately it's private and ~6000 files so I can't easily publicly reproduce.
I've found that switching the legacy config to a flat config radically increases the amount of time no-cycle takes to complete. I am already setting disableScc: true.
In order to try to isolate this issue I've tried to create a minimal pair of configs - one in the legacy format, one in the flat format that only runs the no-cycle rule.
eslint-legacy-nocycle.cjs
// Run eslint with this config:
// time ESLINT_USE_FLAT_CONFIG=false TIMING=1 pnpm exec eslint --config 'eslint-legacy-nocycle.cjs' .
const typeScriptExtensions = ['.ts', '.cts', '.mts', '.tsx'];
const allExtensions = [...typeScriptExtensions, '.js', '.jsx', '.mjs', '.cjs'];
module.exports = {
plugins: [
'eslint-plugin-import',
// All of these are only needed for rule definitions, to stop eslint complaining
// if you mention an rule it doesn't know about in an eslint-disable-next-line comment.
'@babel/eslint-plugin',
'@shopify/eslint-plugin',
'@shopify/eslint-plugin-checkout-web',
'@typescript-eslint/eslint-plugin',
'eslint-plugin-compat',
'eslint-plugin-jest',
'eslint-plugin-jsx-a11y',
'eslint-plugin-node',
'eslint-plugin-promise',
'eslint-plugin-react',
'eslint-plugin-react-hooks',
'eslint-plugin-ssr-friendly',
],
parserOptions: {ecmaVersion: 'latest', sourceType: 'module'},
settings: {
'import/extensions': allExtensions,
'import/external-module-folders': ['node_modules', 'node_modules/@types'],
'import/parsers': {
'@typescript-eslint/parser': typeScriptExtensions,
},
'import/resolver': {
typescript: true,
// node: {extensions: allExtensions},
},
},
rules: {
'import/no-cycle': ['error', {disableScc: true}],
},
overrides: [
{files: ['*.ts', '*.tsx'], parser: '@typescript-eslint/parser'},
],
ignorePatterns: [
'node_modules',
'**/node_modules',
'**/__generated__',
'build',
'coverage',
'dev/extensions/extension.example.tsx',
'app/graphql/*types/*',
'!.storybook',
'packages/session-store/src/proto',
],
};eslint-flat-nocycle.js
// Run eslint with this config:
// time ESLINT_USE_FLAT_CONFIG=true TIMING=1 pnpm exec eslint --config 'eslint-flat-nocycle.js' .
import _import from 'eslint-plugin-import';
import babelEslintPlugin from '@babel/eslint-plugin';
import shopifyEslintPlugin from '@shopify/eslint-plugin';
import typescriptEslintEslintPlugin from '@typescript-eslint/eslint-plugin';
import compat from 'eslint-plugin-compat';
import jest from 'eslint-plugin-jest';
import jsxA11Y from 'eslint-plugin-jsx-a11y';
import node from 'eslint-plugin-node';
import promise from 'eslint-plugin-promise';
import react from 'eslint-plugin-react';
import reactHooks from 'eslint-plugin-react-hooks';
import ssrFriendly from 'eslint-plugin-ssr-friendly';
import tsParser from '@typescript-eslint/parser';
import shopifyEslintPluginCheckoutWeb from '@shopify/eslint-plugin-checkout-web';
const typeScriptExtensions = ['.ts', '.cts', '.mts', '.tsx'];
const allExtensions = [...typeScriptExtensions, '.js', '.jsx', '.mjs', '.cjs'];
export default [
{
ignores: [
'**/node_modules',
'**/node_modules',
'**/__generated__',
'**/build',
'**/coverage',
'dev/extensions/extension.example.tsx',
'app/graphql/*types/*',
'packages/session-store/src/proto',
],
},
{
plugins: {
import: _import,
// All of these are only needed for rule definitions, to stop eslint complaining
// if you mention an rule it doesn't know about in an eslint-disable-next-line comment.
'@babel': babelEslintPlugin,
'@shopify': shopifyEslintPlugin,
'@shopify/checkout-web': shopifyEslintPluginCheckoutWeb,
'@typescript-eslint': typescriptEslintEslintPlugin,
compat,
jest,
'jsx-a11y': jsxA11Y,
node,
promise,
react,
'react-hooks': reactHooks,
'ssr-friendly': ssrFriendly,
},
languageOptions: {ecmaVersion: 'latest', sourceType: 'module'},
settings: {
'import/extensions': allExtensions,
'import/external-module-folders': ['node_modules', 'node_modules/@types'],
'import/parsers': {
'@typescript-eslint/parser': typeScriptExtensions,
},
'import/resolver': {
typescript: true,
// node: {extensions: allExtensions},
},
},
rules: {
'import/no-cycle': ['error', {disableScc: true}],
},
},
{
files: ['**/*.ts', '**/*.tsx'],
languageOptions: {parser: tsParser},
},
];Running these two configs over the full repository sees the flat config take about triple the time of the legacy config:
- Using the legacy config takes 1m37s
- Using the flat config takes 4m47s
This 3x increase is somewhat suprising to me. When I try i use my legacy config with no-cycle enabled it completes in ~2m30s, while when trying to run the flat config version I give up waiting for eslint to complete after 20 minutes - with a fuller config no-cycle seems to take 10x as long.
(ignore the jest/expect-expect some random file in the repo turns that rule on in an in-file directive)
>> time ESLINT_USE_FLAT_CONFIG=false TIMING=1 pnpm exec eslint --config 'eslint-legacy-nocycle.cjs' .
Rule | Time (ms) | Relative
:------------------|----------:|--------:
import/no-cycle | 84829.827 | 100.0%
jest/expect-expect | 4.581 | 0.0%
ESLINT_USE_FLAT_CONFIG=false TIMING=1 pnpm exec eslint --config . 93.28s user 22.82s system 118% cpu 1:37.88 total
>> time ESLINT_USE_FLAT_CONFIG=true TIMING=1 pnpm exec eslint --config 'eslint-flat-nocycle.js' .
Rule | Time (ms) | Relative
:------------------|-----------:|--------:
import/no-cycle | 274185.888 | 100.0%
jest/expect-expect | 4.411 | 0.0%
ESLINT_USE_FLAT_CONFIG=true TIMING=1 pnpm exec eslint --config . 278.24s user 27.20s system 106% cpu 4:47.76 total
When testing using my full config (with no-cycle disabled) I also saw import/namespace and import/no-deprecated regress also.
import/no-deprecatedwith a legacy config took 0.8s, with a flat config it took 10.2simport/namespacewith a legacy config took 11.2s, with a flat config it took 18.3s
// Running my full legacy config, with no-cycle disabled
>> time TIMING=1 pnpm exec eslint .
Rule | Time (ms) | Relative
:---------------------------------|----------:|--------:
import/namespace | 11214.022 | 28.7%
...
import/no-deprecated | 824.473 | 2.1%
...
TIMING=1 pnpm exec eslint . 86.09s user 4.66s system 135% cpu 1:07.00 total
// Running my full flat config, with no-cycle disabled
>> time TIMING=1 pnpm exec eslint .
Rule | Time (ms) | Relative
:---------------------------------|----------:|--------:
import/namespace | 18325.475 | 32.3%
import/no-deprecated | 10224.395 | 18.0%
...
TIMING=1 pnpm exec eslint . 104.67s user 5.00s system 127% cpu 1:26.22 total
As this time regression hurts no-cycle, namespace and no-deprecated, I suspect that this might be something to do with the ExportMapBuilder. I saw that ab0941e makes the cache key used in the ExportMap be constructed differently depending on if a legacy or flat config is used.
I'm not sure how to further debug this to try to isolate the change further. Any thoughts on how I might do so would be appreciated.