Re: Bug with rebase and commit hashes

From: Junio C Hamano <gitster@pobox.com>
Date: Mar 10, 2022, 22:55 UTC
Message-ID: <xmqqsfrpbepd.fsf@gitster.g>
In-Reply-To: <C92B297B-0634-40CC-B1C6-B2A7325BF7DA@gmail.com>

John Cai <johncai86@gmail.com> writes:

Show 7 quoted lines

>> I hit this in production on git 2.30.2 (debian bullseye), but reproduced
>> locally using the latest git main, which is git version 2.35.1.415.gc2162907.
>> In both cases I wiped my user gitconfig, so I'm using only the defaults. (If
>> it helps: with my rebase.autosquash = true, the bad case above does not behave
>> badly and leaves me in detached head as I'd expect.) It's totally possible
>> this isn't _meant_ to work, in which case I think the docs could use an
>> update.

A quick bisect session leads us to 176f5d96 (built-in rebase --autostash: leave the current branch alone if possible, 2018-11-07), but I do not know how much commonality exists in the current code (read: we may well have inherited the bug from there, or we rewrote it completely away but reinvented the same bug in the current code).

with this test script dropped as t/x9999-c.sh --- >8 --- #!/bin/sh

test_description='rebase???'

. ./test-lib.sh

test_expect_success setup '
	git init &&
	>file &&
	git add file &&
	git commit -m initial &&
	git checkout -b side &&
	echo >>file &&
	git commit -a -m side &&
	git checkout master &&
	git tag hold
'

test_expect_success rebase '
	git checkout -B master hold &&
	git rev-parse master >pre &&
	git rebase $(git rev-parse master) $(git rev-parse side) &&
	git rev-parse master >post &&
	test_cmp pre post
'

test_done --- 8< ---

and this as "git bisect run ./runme.sh" script:

--- >8 --- #!/bin/sh

make -j16 NO_OPENSSL=Yes CFLAGS="-g -O" || exit 125 cd t && sh -v ./x9999-c.sh -i -v --- 8< ---

The NO_OPENSSL thing is there only because I started bisecting from an ancient version that no longer compiles out of the box in my environment.