Subject: Re: [PATCH v3] commit-graph: ignore duplicates when merging layers

From: Taylor Blau <[email-masked]>
Date: Thu, 8 Oct 2020 12:42:43 -0400

On Thu, Oct 08, 2020 at 12:26:29PM -0400, Derrick Stolee wrote:
> At this point, any disagreement between rows would be corrupt data
> in one or the other, and it should be caught by the 'verify'
> subcommand. It definitely would be caught by 'verify' in the merged
> layer after the 'write' completes.

Yeah, I'm fine with assuming that this data is correct here, since we
would have already "checked" it after we wrote it.

Of course, that means that if we find another commit-graph bug that
writes bad data and fix it in a future version, old commit-graphs with
duplicate objects have a chance to persist their data.

But, we again have 'git commit-graph verify' as a last resort there, so
I think it's OK.

> At this point, we don't have any evidence that whatever causes the
> duplicate rows could possibly write the wrong data to the duplicate
> rows. I'll keep it in mind as we look for that root cause.

Thanks.

Taylor