Re: [PATCH] builtin/history: unuse the commit buffer after use

[Jeff King <peff@peff.net>]

On Tue, Jun 30, 2026 at 09:13:28AM +0530, Kaartic Sivaraam wrote:

> On 15/06/26 15:18, Patrick Steinhardt wrote:
> > Huh, curious. That seems to hint that we're missing test coverage for
> > this specific scenario, as our test suite doesn't detect this leak.
> > 
> 
> Indeed. The tricky thing is (as mentioned in another thread), this is
> happening only when we get a commit not cached in the commit slab. Once we
> get an idea on how certain commits get cached in the commit slab while
> others don't, we can write a test case that would catch this leak.

Try:

  make SANITIZE=leak
  cd t
  GIT_TEST_COMMIT_GRAPH=1 ./t3451-history-reword.sh -v -i

That shows off the leak. It's possible we should be running the LSan
tests in CI with more feature flags enabled, but I suspect it's just as
likely to miss a case as to add one (i.e., there might be a leak when we
_don't_ use the commit graph). We could do both, but the combinatorics
get expensive.

You could add a specific test that builds a commit graph and runs a
history-reword. That would show off the fix, but it's so specific that I
find it a bit unlikely that it would catch a useful regression in the
future.

So I dunno. I would be content with showing the commands above in the
commit message.

-Peff