Tag initial commits so they skip CI

[lewispb]

I'd like it so that CircleCI is not triggered on the initial commit / empty PR, as per this guide:

https://circleci.com/docs/2.0/skip-build/

The format of the commit message (double -m args) is inspired by this post: https://stackoverflow.com/a/22909204

What do you think? 😄

[sogamoso]

I think that'd be nice.

[balvig]

Thanks for this @lewispb, initially sounds like a good idea!

Just had a couple of thoughts, one perhaps falls in the https://xkcd.com/1172/ camp so we can discuss 😅, but the other probably needs to be checked up on?

1. I start/work on stories in a couple of different ways:

A. Starting from scratch, fixup commits along the way

I have a shortcut for git commit -a --amend --no-edit && git push -f:

$ cp8_cli[master] » cp8 start "new story"
# write code
# write code
$ cp8_cli[jb/new_story] » gfup
# write code
$ cp8_cli[jb/new_story] » gfup
$ cp8_cli[jb/new_story] » cp8 open # done

B. Already wrote some code, hadn't yet created a branch

$ cp8_cli[master] » 
# write code
# write code
$ cp8_cli[master] » git add .
$ cp8_cli[master] » cp8 start "new story"
$ cp8_cli[jb/new_story] » cp8 open # done

For both of these scenarios, I guess this would mean an additional step of editing the commit message in order to kick the CI into gear?

2. In the past, CircleCI seeing a [skip ci] commit on a branch/PR, would never pick up the CI again

...even for subsequent commits! Not sure if that is still the case though. 🤔

[lewispb]

Thanks for looking at this @balvig !

That's a good point you raise, I also use initial commits in different ways.

Maybe what I'm really getting at is I don't want an empty commit to trigger a CI run.

I've actually come at this from a different angle now and whipped up a little prepare-commit-msggit hook instead:

if [ -z "$(git diff --cached --name-status -r)" ]
then
  echo "$(cat $1)\n\n[skip ci]" > $1
fi

So this will add [skip ci] to any empty commit, not just those from cp8_cli.

In regards to your second point reading this (Note: If you push multiple commits at once, a single [ci skip] or [skip ci] will skip the build for all commits.) I got the impression future commits would be OK, but I could be wrong and will need to test this further.

We could add something like the above logic (if commit is empty, add [skip ci]) to cp8_cli, if not then I'm happy to close this as I have a good solution just for me now with the git hook.

[balvig]

Maybe what I'm really getting at is I don't want an empty commit to trigger a CI run.

That was the conclusion I was arriving at as well...makes sense.

I think I will try out that prepare-commit-msg for a while, looks neat!

If it works well, might indeed be useful to include in cp8. Thanks again @lewispb!