Is there an alternative to a “push” hook?

Question

Bitbucket, Github and other services tend to have a \"push\" hook, so that when you push code to the repository, the service can hit a url (possible on a production server),

Answer 1

Bitbucket, Github and other services tend to have a "push" hook

Actually, a Git repo hosting server will have another option with Git 2.10 (Q3 2016): push options.

See commit 3ac8703, commit f6a4e61, commit c714e45, commit 77a9745 (14 Jul 2016) by Stefan Beller (stefanbeller).
^{(Merged by Junio C Hamano -- gitster -- in commit cf27c79, 03 Aug 2016)}

That feature was proposed in this thread:

Allow a user to pass information along a push to the pre/post-receive hook on the remote.

When using a remote that is more than just a plain Git host (e.g. Gerrit, Git{hub/lab}, etc) this may become more obvious: The (server backend specific) push options can instruct the server to:

• open a pull request
• send out emails asking for review
• (un)trigger continuous integration
• set priority for continuous integration (i.e. bots pushing may ask to be treated with lower priority compared to humans)
• ...

Most of these actions can be done on the client side as well, but in these remote-centric workflows it is easier to do that on the remote, which is why we need to transport the information there.

More concrete examples:

• When you want a change in Gerrit to be submitted to refs/heads/master, you push instead to a magic branch refs/for/master and Gerrit will create a change for you (similar to a pull request).
  Instead we could imagine that you push to a magical refs/heads/master with a push option "create-change".
• When pushing to Gerrit you can already attach some of this information by adding a '%' followed by the parameter to the ref, i.e. when interacting with Gerrit it is possible to do things like1:

git push origin HEAD:refs/for/master%draft%topic=example%cc=jon.doe@xxxxxxxxxxx

This is not appealing to our users as it looks like hacks upon hacks to make it work.

It would read better if it was spelled as:

git push origin HEAD:refs/for/master \
  --push-option draft \
  --push-option topic=example \
  --push-option cc=jon.doe@xxxxxxxxxxx

(with a short form that is even easier to type, but this is is more intuitive already)