Does not cache ambiguous modules

[stenin-nikita]

Description

The linter runs for a very long time if the "import/no-cycle" rule is enabled on a large project with typescript. I think the problem is that eslint does not cache all modules. For example, these files will always be parsed again:

• https://github.com/aws/aws-sdk-js/blob/master/clients/all.d.ts
• https://unpkg.com/browse/date-fns@2.29.2/typings.d.ts

Minimal repository for reproduce: https://github.com/stenin-nikita/eslint-plugin-import-bug

Possible solution

This line

eslint-plugin-import/src/ExportMap.js

Line 349 in 68cea3e

if (exportMap == null) return null;

replace with:

if (exportMap == null) {
  exportCache.set(cacheKey, null);
  return null;
}

Locally, this change reduced the check time from 20 to 4 minutes for me

[stenin-nikita]

May be a similar problem here #2076

[ljharb]

That definitely seems like a worthy change. Care to make a PR?

[stenin-nikita]

ОК. I did a PR and wrote a test

[stenin-nikita]

@ljharb When will a version with this fix be released?

[ljharb]

Fixed by #2531.

Releases aren't done on a particular schedule, but hopefully soon.