Coverage report not picking any tests with ghc-7.10 resolver

[jdnavarro]

The tests run properly, but none are shown in the coverage report. This only happens with the ghc-7.10 resolver. The coverage is coming fine when using lts-2.22 resolver or when using a cabal-install sandbox with ghc-7.10.1.

I can provide more detailed information to reproduce the bug, but wanted to confirm this doesn't sound like a known problem.

[mgsloan]

Hi! Sorry for not getting back to this sooner. That doesn't sound like a known problem to me. Do you still have the details about how to reproduce the bug?

[mgsloan]

Also, this might be relevant: #1009

[jdnavarro]

Yes, it's exactly the same error as in #1009. Here it's a way to reproduce it:

$ git clone https://github.com/plutonbrb/nero
$ cd nero
$ stack --stack-yaml=stack-7.8.yaml test --coverage nero:tasty

That works as expected.

But the following gives 100% coverage with 0 tests run:

$ stack --stack-yaml=stack-7.10.yaml test --coverage nero:tasty

My stack binary is coming from Arch Linux AUR, this is what stack --version prints:

Version 0.1.4.0, Git revision 165db5bd77cc88745e0ec8e143275575e5a75d93 (1723 commits) X86_64

I was about to try with HEAD but I'm getting some libtinfo missing dependency issue after the recent Arch Linux GHC upgrade. I'll let you know when I get around fixing it.

[jdnavarro]

I can confirm this also happens with stack-HEAD as of 4e58783.

[mgsloan]

Thanks for the repro, it works for me. Very strange!

[jdnavarro]

@mgsloan what OS are you on? 😕

[mgsloan]

Ubuntu. The repro does work. The very strange thing is the bug.

The verbose logs don't show the two builds doing anything very different, and both of the runs generate .tix files. Looking into it

[jdnavarro]

If I remember correctly with cabal-install the coverage was working with 7.10. Maybe looking into what changed in cabal-install regarding hpc may help.

[mgsloan]

Ah, looks like the problem has something to do with the hashed package identifier stuff, I'm ending up with folders like nero_9bTCpMF7G4UFWJJvtDrIdB in the hpc directory, whereas on 7.8 I'd get nero-0.3.1

[jdnavarro]

Is this related? ttuegel/cabal@1bda428 and haskell/cabal#2457

[mgsloan]

Yup, that's related! The fix was more involved than I'd hoped (parsing ghc-pkg describe results for the package key), but it works!

Please close the issue if it works for you. Thanks for reporting it!

[jdnavarro]

Works now for me. Thank you!

[mgsloan]

@jdnavarro Turns out my implementation approach was flawed. Asking ghc-pkg for the package key only works if the package version you're testing is the exact one that's installed.. I've just pushed a commit that instead parses the key out of package.conf.inplace.

[jdnavarro]

I didn't notice the flaw, but may have created some confusion in the future. Thanks for fixing it.

[mgsloan]

Welcome! I'm actually back on the case, as the fix caused issues: #1162