Re: Revert a single commit in a single file

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

On Fri, Feb 25, 2011 at 19:53, Junio C Hamano <gitster@pobox.com> wrote:
> Thomas Ferris Nicolaisen <tfnico@gmail.com> writes:
>
>> I tried asking the same question on the "newbie" list some time ago:
>>
>> http://groups.google.com/group/git-users/browse_thread/thread/d562b4eeac016711
>>
>> Basically, when I go
>>> git revert <commit> <path>
>>
>> .. my expectation was that a new commit would be made reverting the
>> changes from the old commit, but only for specified path/file.
>>
>> Maybe it's a bit of a corner-case, but still would be nice to have
>> once in a while. What do you think?
>
> I am afraid that it would lead to encouraging people to record a horribly
> broken history, unless you think carefully about what the resulting commit
> log message should describe.  It would look _as if_ you negated the effect
> of the original commit as a whole, but in reality you are only reverting
> just a part of what you chose to revert with <path>.
>
> We do encourage people to record the _reason_ why the particular commit
> was removed by not supporting "-m <message>" option to "git revert"
> command, but the commit template in the editor given to the user should
> make it absolutely clear that the particular partial revert is reverting
> only a part of the original commit, and need additional words to strongly
> encourage to record why only that part and not other parts are reverted.

Agreed, but FWIW where I work I've seen people record "horribly broken
history" already because git-revert doesn't support this, and they
don't know the trick I described.

I also don't agree that the history would be horribly broken. The
message is just an advisory template, it's always the content that
changed that we care about, and we can analyze the history and see
that this chunk is the reverse of a chunk in a previous commit.

But just like we now have:

    Revert "some commit"

    This partially reverts commit <sha1>.

We could have with <path>:

    Revert "some commit"

    This partially reverts commit <sha1>. Only the path <path> has
    been reverted, which is X out of Y files changed in the original
    commit.

Or something like that.