Libraries in the repo

Simon Marlow marlowsd at
Thu Aug 27 06:16:01 EDT 2009

On 26/08/2009 22:32, Duncan Coutts wrote:
> 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.

True, we don't have to do that.

>> 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
> upstream.

Agreed.  Can you think of an easy way to automate it?


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