Unreliability of the build system

[Geoffrey Mainland]

On 06/24/2013 01:16 PM, Ian Lynagh wrote:
> On Mon, Jun 24, 2013 at 12:37:17PM +0100, Geoffrey Mainland wrote:
>>
>> It looks like "/home/gmainlan/ghc/ghc-working-build/bindisttest/install
>> dir/lib/ghc-7.7.20130624/package.conf.d" gets *younger*, leading to the
>> recache error. Rather odd... Any ideas why this is happening?
>
> That's expected: When we install xhtml, we add it to the DB, and the
> cache gets updated.
>
> It looks like the problem is this:
>
> Timestamp 2013-06-24 11:02:14.669097 UTC for
[...]/package.conf.d/package.cache
> Timestamp 2013-06-24 11:02:14.669197 UTC for [...]/package.conf.d (NEWER
>
> I would guess that we assume that when we write package.cache, the
> directory gets updated with the same timestamp; but actually, both use
> the timestamp at which they really happen. This is of course much more
> likely to be a problem if your filesystem has sub-second precision.
>
> If that's it, then it should be possible to fix it by explicitly setting
> the modification time of the directory to match the cache when we write
> the cache in ghc-pkg.

I'm using ZFS, so I suspect that this is indeed the issue.

Thanks,
Geoff