Re: [PATCH] rebase: mark the C reimplementation as an experimental opt-in feature (was Re: [ANNOUNCE] Git v2.20.0-rc1)

From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Nov 29, 2018, 14:30 UTC
Message-ID: <23551.63504.876084.449440@chiark.greenend.org.uk>
In-Reply-To: <nycvar.QRO.7.76.6.1811291516540.41@tvgsbejvaqbjf.bet>

Johannes Schindelin writes ("Re: [PATCH] rebase: mark the C reimplementation as an experimental opt-in feature (was Re: [ANNOUNCE] Git v2.20.0-rc1)"):

> if you could pry more information (or better information) out of that bug
> reporter, that would be nice. Apparently my email address is blacklisted
> by his mail provider, so he is unlikely to have received my previous mail
> (nor will he receive this one, I am sure).

(I did receive this mail. Sorry for the inconvenience, which sadly is inevitable occasionally in the modern email world. FTR in future feel free to send the bounce to postmaster@chiark and I will make a you-shaped hole in my spamfilter. Also with Debian bugs you can launder your messages by, eg, emailing 914695-submitter@bugs.)

> > > At https://bugs.debian.org/914695 is a report of a test regression in
> > > an outside project that is very likely to have been triggered by the
> > > new faster rebase code.

As I wrote in the bug report last night:

 https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=914695#15

 I have investigated and the bug seems to be that git-rebase --onto now
 fails to honour GIT_REFLOG_ACTION for the initial checkout.

 In a successful run with older git I get a reflog like this:

   4833d74 HEAD@{0}: rebase finished: returning to refs/heads/with-preexisting
   4833d74 HEAD@{1}: debrebase new-upstream 2.1-1: rebase: Add another new upstream file
   cabd5ec HEAD@{2}: debrebase new-upstream 2.1-1: rebase: Edit the .c file
   0b362ce HEAD@{3}: debrebase new-upstream 2.1-1: rebase: Add a new upstream file
   29653e5 HEAD@{4}: debrebase new-upstream 2.1-1: rebase: checkout 29653e5a17bee4ac23a68bba3e12bc1f52858ac3
   85e0c46 HEAD@{5}: debrebase: launder for new upstream

 With a newer git I get this:

   6d3fb91 HEAD@{0}: rebase finished: returning to refs/heads/master
   6d3fb91 HEAD@{1}: debrebase new-upstream 2.1-1: rebase: Add another new upstream file
   86c0721 HEAD@{2}: debrebase new-upstream 2.1-1: rebase: Edit the .c file
   50ba56c HEAD@{3}: debrebase new-upstream 2.1-1: rebase: Add a new upstream file
   8272825 HEAD@{4}: rebase: checkout 8272825bb4ff6eba89afa936e32b6460f963a36a
   c78db55 HEAD@{5}: debrebase: launder for new upstream

 This breaks the test because my test suite is checking that I set
 GIT_REFLOG_ACTION appropriately.

 If you want I can provide a minimal test case but this should suffice
 to see the bug I hope...

Regards Ian.

-- 
Ian Jackson <ijackson@chiark.greenend.org.uk>   These opinions are my own.

If I emailed you from an address @fyvzl.net or @evade.org.uk, that is
a private address which bypasses my fierce spamfilter.