Re: [PATCH 3/3] commit-graph: respect 'core.useBloomFilters'

From: Jeff King <peff@peff.net>
Date: Jun 30, 2020, 19:33 UTC
Message-ID: <20200630193340.GA1889576@coredump.intra.peff.net>
In-Reply-To: <20200630192718.GA31522@syl.lan>

On Tue, Jun 30, 2020 at 03:27:18PM -0400, Taylor Blau wrote:

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> So, I'm certainly open to changing it, although I'm not sure that I'm as
> worried about exposing the implementation detail as I am about squatting
> on Bloom filters within Git in general. I don't think that this
> configuration will end up getting used by folks other than server
> administrators and for debugging purposes, so those populations are
> already likely to be aware of changed-path Bloom filters beforehand.

Yeah, the squatting thing is definitely my bigger concern (having been through the "bitmaps" version of the same thing).

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> > It might even be worth considering whether "changed paths" needs more
> > context (or would if we add new features in the future). On a "git
> > commit-graph write" command-line it is perfectly clear, but would
> > core.commitGraphChangedPaths be worth it? It's definitely more specific,
> > but it's also way more ugly. ;)
> 
> Here's a third option what about 'graph.readChangedPaths'. I think that
> Stolee and I discussed a new top-level 'graph' section, since we now
> have a few commit-graph-related configuration variables in 'core'.

Yes, I like that even better. Probably "graph" is sufficiently specific within Git's context, though I guess it _could_ bring to mind "git log --graph". So many overloaded terms. :)

> That's a little shorter, and it adds the verb 'read', which is more
> descriptive than 'use' (I touch on this in the third patch, where I say
> that this configuration variable _doesn't_ affect the '--changed-path'
> option when writing).

Yeah, saying "read" specifically is much nicer.

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> > > +	prepare_repo_settings(the_repository);
> > > +
> > >  	graph = read_commit_graph_one(the_repository, odb);
> >
> > I wondered why we would need this prepare_repo_settings() now, when it
> > should have been needed already to cover core.commitGraph already. I
> > strongly suspect the answer is: "test-tool read-graph" never properly
> > respected core.commitGraph in the first place.
> 
> Yep. Could probably be broken out into a separate patch (or mentioned as
> an aside in this one), but you're right: this helper did not respect
> any configuration that 'prepare_repo_settings' picks up.

I'd probably just note it in the commit message, but I'd be fine with that or with a separate patch.

-Peff