[Nix-dev] [Breaking change] : reducing null usage in nixpkgs.

[Michael Raskin]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

		Hello.
	I have just committed a change to NixPkgs that can break a
configuration that worked before. So I post comments on making it build
again.
	I have nearly finished migration from sumArgs style (only merges
attrSets, terminating null needed) to composedArgsAndFun (also supports
arbitrary functions to act on prepared argument set, requires explicit
.meta.function for every added modification). As composedArgsAndFun does
not allow direct chaining anymore, and *Fun functions were removed,
configuration that relied on them will not work.
	If you used any *Fun calls, use *.meta.function instead and remove
terminating null. If anything like 'aFun {} {} null' was used (direct
passing more than one argument) you will have to specify .meta.function
on the result of each function call. You may also find useful the
sumTwoArgs function that supports both overriding styles (merge and
apply) and accepts function and exactly two arguments.
	The repository state after my latest commit allows to instantiate
all-packages.nix, so conversion should be OK. If you encounter "cannot
coerce function to string" anyway, it can be builderDefsPackage that
gets only the argument resukting from import. Just an empty attrSet
should be added as the second argument in this case.

PS. diff-cutting systems seems to work fine now. Am I the first one to
get commit logs correctly cut in the mailing list?

Raskin
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.9 (GNU/Linux)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org

iQEcBAEBAgAGBQJIpLMPAAoJEE6tnN0aWvw34KAIAJ36dHoiszlrCLT9OnHG2SOG
UMtkVlUV4pg4Nu0Ob8Jj4lyaWYN8hmBdxQewVJMhbCxJKL/lV2XZB86zbKaBVQoQ
gHaDuYUWyeA9+gboXGRivB7E1Nb7wnGkYqX8jzOlSTJqz+fSplEDKmsa3eyKQqpp
G4urjtgdCP5VsmPzVzKfpkOvicpHT8Ho+xhROHcbqRbtpT5gUtd7QeQ+NIHAbVHD
+6une8OdbuV9L6ltG2UqLg594WkvEsQEBd1jdHZ5HHpbKCgnnvzftK4H/iaKfKN1
z10WD1s3z2n61NlzJfQQxAjRw23NqdShxAZwhK4MsMjqBMzcPGxyWlC1hZ8uN0M=
=8/mi
-----END PGP SIGNATURE-----