build-depends in global section in new-style .cabal files are ignored

[bos]

(Imported from Trac #424, reported by @dcoutts on 2008-12-03)

http://hpaste.org/12669

In a .cabal file like:

name:          music
version:       0.0
cabal-version: >= 1.2
build-type:    Simple
build-depends: base == 4
library
  exposed-modules:
    Music

which uses new-style syntax but puts the build-depends in the global section, the build-depends get ignored.

It should either warn or reject this, or it should automatically propagate such global options into each buildable component.

[bos]

(Imported comment by @dcoutts on 2008-12-03)

Should be done as part of the rewrite of the parser and representation of package descriptions in Cabal-1.8.

[bgamari]

I take it there has been no progress on this? This would be very nice to cut down on the amount of repetition in Cabal files specifying multiple executables, even if this is a practice which is frowned upon.

[manzyuk]

Is this still an issue? I see a comment in Cabal/Distribution/PackageDescription/Parse.hs:

        -- "build-depends" is a local field now.  To be backwards
        -- compatible, we still allow it as a global field in old-style
        -- package description files and translate it to a local field by
        -- adding it to every non-empty section

which makes me think that what Duncan is suggesting:

or it should automatically propagate such global options into each buildable component.

has already been implemented.

[kosmikus]

@manzyuk I'm not sure. If you can test and confirm that it actually works, then I think we can close this.

[dcoutts]

For new-style files this should be a warning. The global thing is only there for old style files.

[jsl]

The original issue reported here (in 2008) is that Cabal didn't warn when build-depends appeared in the global section of a new cabal file. I just tested with a new cabal, and it does warn when I put this clause in the global section (output: "Warning: atomic-write.cabal: Unknown fields: build-depends (line 57)").

Can we close this ticket, and re-open or create a new ticket if there are other problems with build-depends?

/cc @tibbe