Relative paths in cabal.project files don't work as expected

[mpickering]

I want to pass some options to a dependency. So I added the flags to my cabal.project file as follows.

package groups                                                                  
    ghc-options: -fwrite-ide-info -hiedir=./test/hie-files

However, now groups is rebuilt but the hie files are not in the directory I specified and nor are they anywhere to be seen at all! I can't find them anywhere in my home directory.

If I write an absolute path it works fine.

Why I consider this a bug, if I cabal get groups, modify the cabal file to add the ghc-options and add it as a local dependency then the path is resolved relative to the cabal file.

[pranaysashank]

I came across the same problem today.

nor are they anywhere to be seen at all!

They are being written into the tmp directory in dist-newstyle, like in ./dist-newstyle/tmp/src-6743/groups/0.2.0/test/hie-files.

The situation seems to be the same with any dir option like hidir, stubdir, etc.,

[phadej]

Relative is ambiguous. Relative to what? And @pranaysashank comment highlights that.

Note that ghc-options are opaque field to cabal. It doesn't know there are some paths, so cannot (and if you ask me ,should never) mangle them, so they are relative to the CWD of GHC process, whatever that happens to be.

There are discussion somewhere that in config parsing cabal should recognise e.g. $xdgcache directory. Similarly there could an anchor for the project root directory. That would be more principal solution.