No coverage reports

[bitPogo]

💥 Regression Report

After updating from 26.4.0 -> 26.4.2, I get no more a valid coverage report in jest.

Last working version

Worked up to version: 26.4.0

Stopped working in version: 26.4.2

To Reproduce

Steps to reproduce the behavior:

1. write your app with tests
2. run the coverage report in jest (jest --coverage) with version 26.4.0
3. update to 26.4.2
4. run the coverage report again

Expected behavior

The coverage report should be shown as in version 26.4.0

envinfo

System:
    OS: MacOS 10.15.7

Npm packages:
    jest: 26.4.2
    typescript: 4.0.3
   @babel/core :  ^7.12.3 ,
   @babel/plugin-syntax-jsx :  ^7.12.1 ,
   @babel/preset-env :  ^7.12.1 ,
   @babel/preset-react :  ^7.12.1 ,
   @babel/preset-typescript :  ^7.12.1 ,
   babel-loader :  ^8.1.0 ,

[ahnpnl]

duplicate with #2080 , please check the solution there

[bitPogo]

Maybe there this is a duplicate but not of the issue you refer to.

[ahnpnl]

does it work if you clear jest cache ?

[bitPogo]

I cleared the cache, but it did not helped it...I tried several (to many to recall them all) things to bring it back, but only after the downgrade to 26.4.0 it worked again.

[ahnpnl]

clear cache works for me with 26.4.3. What I did is:

• Upgrade to 26.4.3
• Run yarn jest --clearCache
• Run test again and coverage shows.

I actually linked the wrong duplicated issue, already corrected the comment.

[bitPogo]

I will check it out by tomorrow and report back. Thanks so far!

[bitPogo]

Confirmed, it works! Thanks again!

[arty-name]

I have found that clearing the jest cache only fixes the coverage for a single run of jest. Following jest runs produce no coverage again. Clearing the cache before every jest run doesn't sound like a viable solution. Would you consider that an issue @ahnpnl?

[ahnpnl]

Ok that is more than an issue indeed.

[ahnpnl]

@arty-name for some reasons I cannot reproduce anymore this issue with jest 26.6.3 and ts-jest 26.4.3.

Updated: ok I managed to get one reproduce scenario. Some repos I don't see the issue, weird.

[kamilmielnik]

I'm also experiencing this issue. (26.4.0 & 26.4.3).
It's weird, it's not 100% deterministic.
Doing npx jest --clearCache (as per advice above) didn't have any effect for me.
Using --no-cache flag for all my scripts using jest CLI did the trick.