Prevent a segfault in createProcess on Mac

[neilmayhew]

The new test segfaults without the corresponding change in find_in_search_path

Using . is slightly less efficient than not using a working directory at all, but it avoids adding a third code branch and the consequent additional duplication of sprintf code.

Closes #295

[neilmayhew]

I tested this on Mac and Linux as follows:

nix-shell --pure -p haskell.compiler.ghc945 autoconf
autoreconf -i
ghc Setup.hs
./Setup configure --enable-tests
./Setup build
./Setup test

[bgamari]

Thank you, @neilmayhew ! This looks good.

[neilmayhew]

Thanks for approving and merging.

Since this is a boot package, I assume it will be a while before the fix gets into a version that we can use in an application.

Is there any chance this would be backported into a version of ghc 9.4? Or is there now a way to use a non-default version of a boot package?

[Bodigrim]

Or is there now a way to use a non-default version of a boot package?

It depends on your other dependencies, but with process you can likely say cabal build --constraint 'process >= X.Y.Z' and Cabal will rebuild everything in the world.

GHC 9.4.6 is in works right now, you might want to chime in https://gitlab.haskell.org/ghc/ghc/-/issues/23760 and https://gitlab.haskell.org/ghc/ghc/-/issues/23710

[andreasabel]

I chimed in on https://gitlab.haskell.org/ghc/ghc/-/issues/23760 because not even GHCs 9.4.7 and 9.6.3 contain this important bugfix.