From: Elijah Newren <newren@gmail.com>
To: Git Mailing List <git@vger.kernel.org>
Subject: Fun puzzle: successful merge's contents depends on...commit timestamps?
Date: Fri, 18 May 2018 20:07:45 -0700 [thread overview]
Message-ID: <CABPp-BFc1OLYKzS5rauOehvEugPc0oGMJp-NMEAmVMW7QR=4Eg@mail.gmail.com> (raw)
Check this out; I merge another branch successfully:
$ git merge -m F $othersha; echo $?
0
This is just a simple test repo:
$ git log --oneline
18f5e65 (HEAD -> master) F
7472b46 E
ea0d801 D
4486f96 C
7727e3b B
ee47c13 A
Below it is important to note that one commit was made at 1526194997,
and this value doesn't appear anywhere else in fast-export output:
$ git fast-export --no-data master | grep 1526194997
author Elijah Newren <newren@gmail.com> 1526194997 -0700
committer Elijah Newren <newren@gmail.com> 1526194997 -0700
Let's create a new branch and rewrite history ONLY changing that one timestamp:
$ git checkout -b redo
$ git fast-export --no-data redo | \
sed -e s/1526194997/1500000000/ | \
git fast-import --quiet --force
At this point, the trees for 'master' and 'redo' match, as you'd expect:
$ git diff --quiet master HEAD; echo $?
0
Let's redo that merge, shall we?:
$ git checkout --quiet 'redo^1'
$ git merge -m newF 'redo^2'; echo $?
$ 0
Did we get the same merge result? Nope:
$ git diff --quiet master HEAD; echo $?
1
I believe there are about half a dozen solutions to this puzzle. Can you find
at least one?
reply other threads:[~2018-05-19 3:07 UTC|newest]
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