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Any way to set the default subject line of commit message when you do a git revert?

23d 12h ago by programming.dev/u/duckduckduck in git@programming.dev

Whenever I do a git revert I go into an edit session with the following pre-filled.

Revert "wip: does this work?"

This reverts commit ad21a2ae23166b3f3cddoooooooom94821e3cdb4.

# Please enter the commit message for your changes. Lines starting
# with '#' will be ignored, and an empty message aborts the commit.
...

...and so on.

I like to use conventional commits, so I change this to revert: "wip: does this work?".

Is there a way to get the initial template for the revert commit message to appear this way by default? Lowercase, and with a colon.

UPDATE This is what I came up with

#!/bin/bash

COMMIT_MSG_FILE=$1

old_subject_line=$(head -1 $COMMIT_MSG_FILE)

# Not a revert
if [[ ! "$old_subject_line" =~ ^Revert\ \" ]]
then
    exit 0
fi

new_subject_line=$(echo $old_subject_line|sed 's/^Revert/revert:/')

sed -i "1s/.*/$new_subject_line/" $COMMIT_MSG_FILE

Curiously, the case where two "Reverts" in a row become a "Reapply" doesn't come up like I thought it would. Maybe it only happens if you use the default Revert "yada yada yada" subject line.

Thanks for the 2am nerd snipe :D

You can do this via git hooks and a script. Specifically the prepare-commit-msg hook (.git/hooks/prepare-commit-msg). In your script, check for the GIT_REFLOG_ACTION env variable, and check if its value is "revert". If so, you are in a revert, and you can echo/printf out whatever you would like in your template.

Might be a bit more work to get to where you want, but hopefully that points you in the right direction?

Thanks that is a great start, and even better gives me an excuse to faff about with scripting. I'll share what I come up with!

EDIT Oh interesting, in my debugging I found out that if you revert a revert now (git version 2.43.0) that the subject line reads "Reapply" instead of "Revert "Revert "..."""

Updated OP with what I came up with. I wasn't able to make use of $GIT_REFLOG_ACTION -- for some reason it was blank in every case, but reading the first line of the existing commit message, if it exists, does the trick.

I do foresee a potential problem if you're doing like an interactive rebase for example, and you go to edit a commit message that starts like the default "Revert " style--that could be surprising... Maybe some other cases I haven't thought of too, but yeah, works for me. Thanks for pointing me in the right direction!

And yeah I made an account just to ask this question. Hello! Nice looking server you've got here. 🖐