Libraries in the repo

Duncan Coutts duncan.coutts at
Wed Aug 26 17:32:28 EDT 2009

On Wed, 2009-08-26 at 17:15 +0100, Simon Marlow wrote:

>   * Sometimes we want to make local modifications to INDEPENDENT
>     libraries:
>       - when GHC adds a new warning, we need to fix instances of the
>         warning in the library to keep the GHC build warning-free.

I have to say I think this one is rather dubious. What is wrong with
just allowing warnings in these independent libs until they get fixed
upstream? I know ghc's build system sets -Werror on them, but I don't
see that as essential, especially for new warnings added in ghc head.

> Experience with Cabal and bytestring has shown that (1) can work for
> INDPENDENT libraries, but only if we're careful not to get too
> out-of-sync (as we did with bytestring).  In the case of Cabal, we never 
> have local changes in our branch that aren't in Cabal HEAD, and that 
> works well.

It requires an attentive maintainer to notice when people forget to push
upstream (as they inevitably do on occasion). If it goes unnoticed for
too long then ghc ends up with a forked repo that cannot sanely be
synced from the upstream repo (like bytestring).

I suggest if we stick with the independent repo approach that we have
some automation to check that changes are indeed getting pushed


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