haddock segfaults

[jchia]

Summary: Haddock segfaults when I do 'stack haddock' on a new nightly-2018-05-22 project that has haskell-src-exts as a dependency.

Originally, I made an issue here: commercialhaskell/stack#4036

Unfortunately, being unfamiliar with the intricacies of stack and cabal, I don't have a smaller test case than the following:

1. Start with a fresh installation (official stack 1.7.1 binary installed, no ~/.stack/ directory)
2. stack new --resolver=nightly-2018-05-22 test
3. cd test
4. Edit package.yaml, adding haskell-src-exts to dependencies.
5. stack haddock and witness the crash.

It's clear that haddock segfaulted, not merely exited with a regular failure code.

[RobertFischer]

I am seeing this, too.

[harpocrates]

The segfault (or hanging) behaviour is triggered in the Happy-generated InternalParser.hs file when generating hyperlinked sources. The actual bug is small, but the frustrating segfault/hanging behaviour is courtesy of GHC's lexTokenStream.

Besides disabling hyperlinked sources completely, I'm not sure what you can do to work around this (here is yet another reason to want a module level way of hiding modules from the Hyperlinker backend).

[RobertFischer]

Thank you very much.

…

On Tue, Jun 5, 2018, 13:47 Alexander Biehl ***@***.***> wrote: Closed #837 <#837> via #846 <#846>. — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#837 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AABO1ww5fSzsSbv8pTT4AxqjBecFRW5_ks5t5sQngaJpZM4UKvEj> .

[noxecane]

This still segfaults with haskell-src-exts. Except the fix is not part of GHC 8.4.3. This time I am using lts-12.6 unlike the original complaint.

Relevent versions

stack: 1.7.1
ghc: 8.4.3
haddock: 2.20.0

It crashes exactly the same way @jchia described.