Joshua Phillips [off-list ref] writes:
I've found a case where git pull --rebase discards commits in my branch
if the remote-tracking branch was rewound (and the remote tracking
branch's reflog contains my branch's latest commit). This is due to
git-pull's usage of git merge-base --fork-point.
On one hand, this behaviour might be correct since the remote repository
essentially removed that commit from master by 'reset --hard'. On the
other hand, I was surprised that git pull --rebase discarded a commit in
my branch.
Yup, that sounds like a bad way to handle the situation. After all,
the upstream may have first accepted your first attempt, and then
decided that it was premature and rewound it, expecting you to give
an improved reroll. But I also agree with you that it may be
correct to drop it because the upstream already rejected it.
Since Git cannot tell between these two cases, we should play safer
than what the current code does, I would think.
Hi Junio,
On 23/08/2016 21:28, Junio C Hamano wrote:
Joshua Phillips [off-list ref] writes:
quoted
I've found a case where git pull --rebase discards commits in my branch
if the remote-tracking branch was rewound (and the remote tracking
branch's reflog contains my branch's latest commit). This is due to
git-pull's usage of git merge-base --fork-point.
On one hand, this behaviour might be correct since the remote repository
essentially removed that commit from master by 'reset --hard'. On the
other hand, I was surprised that git pull --rebase discarded a commit in
my branch.
Yup, that sounds like a bad way to handle the situation. After all,
the upstream may have first accepted your first attempt, and then
decided that it was premature and rewound it, expecting you to give
an improved reroll. But I also agree with you that it may be
correct to drop it because the upstream already rejected it.
Since Git cannot tell between these two cases, we should play safer
than what the current code does, I would think.
Were there any news in this regards so far? Would it be (more)
sensible/safe to report the dropped commits, too? Something like:
Dropping: Commit B
Applying: Commit X
Applying: Commit Y
... where "Applying: *" are standard "git rebase" output lines, and
"Dropping: *" a newly proposed one (example graphs (1.1) to (1.3)
shown below[1]).
That said, applied commits might even be considered pretty
uninteresting here (as they`re kept/transferred over anyway), a noise
drowning what otherwise might be really important - the dropped/lost
ones...?
It does feel a bit scary learning that you may _silently_ lose
commits, especially as --fork-point is used by default for both
vanilla `git rebase` and `git pull --rebase`.
P.S. As a relatively new user, I actually just got aware of this
behavior from another, recently posted e-mail[2], having me
investigate further, yet thought replying here might be better as it
got some attention already (adding author of that other e-mail,
Laszlo Kiss, to Cc).
Regards,
Buga
[1] Example graphs:
(1.1) ---A---B (master)
\
X---Y (topic)
(1.2) C---D (master)
/
---A---B
\
X---Y (topic)
(1.3) X'---Y' (topic)
/
C---D (master)
/
---A
Note that I didn`t use "origin/master" but just "master" on purpose,
as the branch being tracked doesn`t have to be a remote one, making
the lost local commits confusion even greater.
[2] https://public-inbox.org/git/CAO0LFki4PN8zz2xpoSpjTHJGS=NG_suQYR27EcmzEMiaCw9kuA@mail.gmail.com/