Jest cache incorrectly resolving modules

[imjared]

Before creating an issue please check the following:

• you are using the latest version of Jest
  ✅ "jest": "^20.0.4",
• try re-installing your node_modules folder
  ✅ so.many.times.
• run Jest once with --no-cache to see if that fixes the problem you are experiencing.
  ✅ tried it.

Please provide your exact Jest configuration and mention your Jest, node, yarn/npm version and operating system.

"jest": {
  "verbose": true,
  "resetModules": true
}

• jest version: 20.0.4 21.0.1
• node version: 7.4.0 8.1.3
• yarn version: 0.27.5 1.3.2
• npm version: 4.0.5 5.6.0
• OS = MacOS Sierra 10.12.5 (16F73) MacOS High Sierra 10.13.2

---

Repo with reproduction steps here:

https://github.com/imjared/jest-resolver-failure-repro

Description

We've been having issues with (what seems to be) Jest's module resolver and how it interacts with Jest's cache.

Our .babelrc uses the module-resolver plugin so we can use paths relative to our src directory (effectively the root of our project) rather than from each file. For example, import Bar from '../../components/foo/bar' might end up being import Bar from 'components/foo/bar'.

This test case is reduced to show our i18n helper that lives in src/utils/i18n.js. We use this in our translation JSON files to provide fallbacks for translations when a locale may be missing or a locale like Germany might provide translations for Austria and Switzerland.

When we run tests, our i18n helper runs as expected as long as it exists at what would be the same relative path. For example, in this repo, the path from Component1/translations/index.js to the i18n module would be:

import { i18n } from '../../../utils/i18n.js';

When we test a component that has a different relative path, the i18n module can not be found. For example, the path from Component2/NestedComponent/translations/index.js to the i18n module would be one level deeper:

import { i18n } from '../../../../utils/i18n.js';

This causes tests to fail.

Reproduction

1. Clone this repo
2. run yarn to install dependencies. Ensure you have jest-cli installed
3. after running yarn, kick off the tests by running jest or yarn test. The first test run primes the Jest cache so tests should pass fine. Run tests again.

Expected Behavior:
Tests still pass. Paths resolve as they should.

Actual Behavior:
Tests fail. The error is as follows:

Cannot find module '../../../../utils/i18n' from 'index.js'
      
      at Resolver.resolveModule (node_modules/jest-resolve/build/index.js:179:17)
      at Object.<anonymous> (src/components/Component1/translations/index.js:1:229)

It seems that the module can't be found because the path that's four directories up is actually the path used from the NestedComponent's translation index file.

Running the tests again with either jest --no-cache or yarn test:nocache should pass.

[stewartyu]

I'm having the same problem too!

[imjared]

I've been tinkering with this a bit more and found some additional behavior that might be helpful. If translations/index.js is the same file (has the same content) at various depths, we'll have the issue. If the file differs, Jest seems to cache it separately. For example:

In my demo repo, in Component2/NestedComponent/translations, add a file called en-CA.json with the following contents:

{
  "content": "Here is a nested component's Canadian content"
}

Component2/NestedComponent/translations/index.js, add the line 'en-CA': require('./en-CA.json'), to the default export.

Clear the jest cache. I did this by deleting a directory at /private/var/folders/__/_bx_5btj1p33ywck5vj1w5hw0000gn/T/jest_dx/jest-transform-cache-26ea998c02504a11f13e60853d300d2f-1a35dc2915d13d52ffe0e46ba61699d5/. If you're debugging along with me, I bet you know how to find your cache dir 😉 [1]

Run Jest once to prime the cache. Run Jest again and see that the tests still pass. If you investigate the cache directory that's been recreated, you'll see there are two instances of files called index_.... One should have the en-US and en-CA imports, one with only the en-US import.

---

[1] If anyone is reading along, you can find your cache directory by running jest --showConfig. It's the config.cacheDirectory value.

[mmahalwy]

same problem. any ideas?

[wschurman]

@mmahalwy - may want to check that your NODE_PATH environment variable doesn't contain any non-existent directories (see #4453 (comment))

[imjared]

this seems to finally be resolved with "jest": "^22.3.0",

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