threads / discuss / 27111

spurious fail of git merge after rebasing

Subject: spurious fail of git merge after rebasing

## tl;dr

3 messages between Apr 15, 2011 and Apr 18, 2011.

replies: 2people: 2as markdown or json

D. A. van Delft· Apr 15, 2011, 22:45 UTC · lore

Hi,

not sure if this is the right place, but I couldn't find a bugzilla or something for git.

Point is, I have found a scenario where sometimes git fails on a specific merge. Each time I start with the same identical git repository (archived once and restored each time before a run) and run the same fixed series of rebases and merges on it. Once in a while it fails with a merge conflict, sometimes at first try, sometimes after 10+ times. I have a canned set of testcases which reproduces this behaviour. I have also narrowed it down somewhat on how to work around, or prevent it from occurring.

However, given that it doesn't always fail or succeed, is unexpected.

regards, Danny A. van Delft

Jeff King· Apr 18, 2011, 06:10 UTC · re: D. A. van Delft · lore

Re: spurious fail of git merge after rebasing

On Sat, Apr 16, 2011 at 12:45:12AM +0200, D. A. van Delft wrote:

Show 12 quoted lines

> Point is, I have found a scenario where sometimes git fails on 
> a specific merge.
> Each time I start with the same identical git repository 
> (archived once and restored each time before a run) and run 
> the same fixed series of rebases and merges on it. Once in a 
> while it fails with a merge conflict, sometimes at first try, 
> sometimes after 10+ times. I have a canned set of testcases 
> which reproduces this behaviour. I have also narrowed it down 
> somewhat on how to work around, or prevent it from occurring. 
> 
> However, given that it doesn't always fail or succeed, is 
> unexpected.

Yeah, git should generally be deterministic. Can you show us your test case?

-Peff

Danny van Delft· Apr 18, 2011, 07:37 UTC · re: D. A. van Delft · lore

Re: spurious fail of git merge after rebasing

Added attachment contains testcases, in three separate dirs.

I came about this problem during development of a script that generates git commands to rebase a graph, with all its wanted sub graphs, starting at one commit onto another commit. The "runtest" script is the output of this script, hence the strange looking branchnames during its operation.

regards,

-- 
Danny
Op zaterdag 16 april 2011 om 00:45 schreef D. A. van Delft:
> Hi,
> 
> not sure if this is the right place, but I couldn't find a
> bugzilla or something for git.
> 
> Point is, I have found a scenario where sometimes git fails
> on a specific merge.
> Each time I start with the same identical git repository
> (archived once and restored each time before a run) and run
> the same fixed series of rebases and merges on it. Once in
> a while it fails with a merge conflict, sometimes at first
> try, sometimes after 10+ times. I have a canned set of
> testcases which reproduces this behaviour. I have also
> narrowed it down somewhat on how to work around, or
> prevent it from occurring.
> 
> However, given that it doesn't always fail or succeed, is
> unexpected.
> 
> regards,
> Danny A. van Delft