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bisect: do not allow when a rebase/merge/am/revert is in progress - #2421

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thunder-coding wants to merge 4 commits into
git:masterfrom
thunder-coding:safer-bisect
Open

thunder-coding wants to merge 4 commits into
git:masterfrom
thunder-coding:safer-bisect

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@thunder-coding

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This got to my attention in
https://chaos.social/@karolherbst/117322259078547068. Just going
through the source code, I found that bisect is allowed to run even when
a rebase/merge/am/revert is in progress. When a rebase is in progress,
bisect simply overwrites the rebase state and starts the bisect without
any warning. This can lead to loss of work and confusion. Also since we
are it, I think we should also check for existing bisect/merge/am before
starting a new bisect. During merge, bisect seems to glitch out with Git
v2.55.0 (as packaged by Arch) when there are unmerged files, which kind
of leaves the tree in an uncertain state

Bisecting: revisions left to test after this (roughly steps)
: needs merge
error: you need to resolve your current index first

Now although you actually can't bisect as tree needs to resolve the current
index first, git bisect log shows that the good and bad states are being
logged.

The check for existing bisect/merge/am/revert is inspired from
die_if_some_operation_in_progress() in builtin/checkout.c.

The patches are split into 4 commits as I originally created them. You
might be interested in doing a rebase and merge instead of pulling this
directly

bisecting when any of the mentioned is going on results in the bisect
overwriting any changes made during ongoing rebase/merge/am/revert
without any warnings, or prompt messages. So it's ideal to refuse to do
that, and ask the user to manually do it before starting a bisect

Signed-off-by: Yaksh Bariya <yakshbari4@gmail.com>
Or else a started bisect can never end as bisect command needs to run to
end the bisect. Classic textbook deadlock problem :)

Signed-off-by: Yaksh Bariya <yakshbari4@gmail.com>
…d-term>

Earlier missed, as seems like git is special case handling it by
manually going through it when it doesn't match any of the subcommand.
Makes sense since the good/bad term can not be known beforehand

This is the cleanest way I saw it could be done without hurting code
readiblity

Signed-off-by: Yaksh Bariya <yakshbari4@gmail.com>
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@gitgitgadget-git

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There is an issue in commit 586bdc8:
bisect: re order switches for checking bisect when already bisect is

  • The first line must be separated from the rest by an empty line

makes sense to check it last

Signed-off-by: Yaksh Bariya <yakshbari4@gmail.com>

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