I want to use git bisect to fix some bugs.
git clone [email protected]:pingcap/tidb-engine-ext.git
git checkout raftstore-proxy
git bisect start
git bisect good 45ce5b9584d618bc777877be8a77cb94f61b8410
git bisect bad 8acb2b2ed0eb1576e7961149bde27cb1568ec39e
And it suggests me to check commit e868450a9f982b25790262c9e86ff1e27ab8dc2e, and I will call it mid.
It is quite strage when I start to check commit date of those commits
git show --no-patch --no-notes --pretty='%ci %ai' 45ce5b9584d618bc777877be8a77cb94f61b8410
# 2021-06-24 16:15:24 +0800 2021-06-24 16:15:24 +0800
git show --no-patch --no-notes --pretty='%ci %ai' e868450a9f982b25790262c9e86ff1e27ab8dc2e
# 2020-11-27 14:59:01 +0800 2020-11-27 14:59:01 +0800
git show --no-patch --no-notes --pretty='%ci %ai' 8acb2b2ed0eb1576e7961149bde27cb1568ec39e
# 2021-09-28 12:57:47 +0800 2021-09-27 13:50:37 +0800
I think commit date of e868450a9f982b25790262c9e86ff1e27ab8dc2e should be between [good,bad], even if we take potential cherry-pick/rebase into account, since every opertion will change commit date. So it is strage here.
Meanwhile, I also check if good and bad have common merge-base, and the result is yes. I think it means there is a chain that good -> ... -> bad, so I can bisect on this chain
git merge-base 45ce5b9584d618bc777877be8a77cb94f61b8410 8acb2b2ed0eb1576e7961149bde27cb1568ec39e
45ce5b9584d618bc777877be8a77cb94f61b8410
However, we I check merge base of bad/mid and mid/good, thing get stranger. It shows merge base of good and mid is neither good nor mid, but why does this happen?
git merge-base 45ce5b9584d618bc777877be8a77cb94f61b8410 e868450a9f982b25790262c9e86ff1e27ab8dc2e
# eb82614fc19345f363458e66b53aaff5c57563d5
git merge-base e868450a9f982b25790262c9e86ff1e27ab8dc2e 8acb2b2ed0eb1576e7961149bde27cb1568ec39e
# e868450a9f982b25790262c9e86ff1e27ab8dc2e