cabal sdist runs alex and happy on the maintainers machine

[cartazio]

cabal sdist runs alex and happy on the maintainers machine, and I think that any .y .x files should be processed in the client users side. Otherwise, when a breaking change happens to alex and happy and associated GHC versions, like 7.8, every lib maintainer which has a lib using alex and happy have to prepare a fresh sdist using a newer alex and happy, (they have to do this even if nothing in the code has otherwise changed!!!)

I've hit this with pandoc jgm/pandoc#1136
and others have it it with language-c haskell/c2hs#64#issuecomment-35059925 (which seems to be unmaintained)

[cartazio]

and it says something that both manuel and I find this behavior quite surprising!

[23Skidoo]

See #130. We want to associate metadata with each pre-generated file so that in the preprocess phase we could tell whether the file was produced by an older version of a preprocessor than the one installed.

[cartazio]

@23Skidoo why is it run on the maintainers side rather than the builder's side?

[cartazio]

is this for any module that has preprocessing (eg when I include a suitable pragma for some custom preprocessor), or just certain ones that are "portable" and have special status like Happy and Alex?! Not every preprocessor is system independent!

[23Skidoo]

Yes, it happens only for platform-independent preprocessors.

I think that the main rationale for this feature is bootstrapping (for example, happy's source tree includes .y files and you'd need to have happy installed to install happy without it).

[cartazio]

gotcha

[sethfowler]

greencard is hitting this too, unfortunately.

[ttuegel]

Duplicate of #130 (literally the oldest issue).