Re: 2.29.0.rc0.windows.1: Duplicate commit id error message when fetching

[Derrick Stolee <stolee@gmail.com>]

On 10/9/2020 1:12 PM, Thomas Braun wrote:
> Sure! Please find them attached. I retried with no jobs parameter as
> well, same issues.
> 
> I did some more bisecting of my git settings. And now it's getting
> embarrassing...
> 
> Can you reproduce it if you do
> 
> git config core.commitGraph false
> git config fetch.writeCommitGraph true
> ?

I _can_ repro it in this case! I think there must be something
very interesting going on where the commit-graph is parsed in
_some_ places, but not in others. This is something that I can
really start to dig into.

It's important to note that the final "git fetch" adds a layer
to the commit-graph chain even though we shouldn't be reading
from the commit-graph file! This is an unusual situation that
is unexpected, but should be handled correctly.

My gut reaction is to end early in any commit-graph write
method when core.commitGraph is false. But that only papers
over the real issue here. I'll keep digging.

Thanks for the logs, they may come in handy!
-Stolee