Re: why does "git revert" commit even if i try to bail with ":q!"?

[Kevin Daudt <me@ikke.info>]

On Tue, Mar 12, 2019 at 01:22:51PM -0400, Robert P. J. Day wrote:
> 
>   never noticed this before ... when i do a regular "git commit" and
> enter my "vi" edit session and change my mind, i can bail with ":q!",
> regardless of what i've set up as a commit message, and i'll see:
> 
>   Aborting commit due to empty commit message.
> 
> however, i was just playing with "git revert" and, after i ran:
> 
>   $ git revert <commit SHA>
> 
> i was dumped into another vi edit session:
> 
> Revert "HTTP->HTTPS"
> 
> This reverts commit 2965b41fd84a1a76f56984ecdf6c123d1992730f.
> 
> # Please enter the commit message for your changes. Lines starting
> # with '#' will be ignored, and an empty message aborts the commit.
> #
> # On branch master
> # Your branch is up to date with 'rpjday/master'.
> #
> # Changes to be committed:
> #       modified:   book/01-introduction/sections/installing.asc
> #
> 
>   again, simulating that i changed my mind, i just typed ":q!", but
> the revert went ahead, anyway. i tried again, this time completely
> deleting all the lines from the commit msg (as the template
> suggested), but the revert *still* completed after typing ":q!".
> 
>   it was only after deleting all the lines and using ":wq" that the
> revert was cancelled:
> 
>   Aborting commit due to empty commit message.
> 
> that seems ... inconsistent. am i misunderstanding something?
> 
> rday

The only reason why `:q!` works just for comitting is because there is
no default message, so the final message ends up empty.

When you do things like git revert or git ocmmit --amend, there is
already a commit message, which you are then editing. When you quit
without saving, the existing message remains and git uses that.

vim has a command to let it exit with an error return code: `:cq`. This
makes git something went wrong with editing the message, causing git to
abort the commit.