[jibcage]

I personally prefer including issues as git trailers:

    fix thing in foo

    Issue: ABC-123

Git has plenty of builtins for parsing and formatting these trailers, so you can easily create custom git log aliases that let you see them inline and parse them for use with CI.

[epmatsw]

I think you’re the first person in this comment section to mention this. Git has a structure for machine-readable structured data. Put it there, not in free text fields for humans.

[codethief]

That's all good and well but the UX sucks. I usually have dozens of commands like

  git commit -m "PROJECT-XXXX Foo the bar to baz the qux"

in my shell history, which means 1) I can easily create follow-up commits under the same ticket number (no having to type the ticket number again), 2) I don't have to keep remembering the ticket number once I created the first commit on the given ticket. I'm sure I could set up an elaborate set of shell scripts and git aliases to auto-insert a ticket number as structured data at the bottom of each of my commits. But good luck convincing the rest of your team to do that.

Also, having the ticket number in the subject line means every git-related tool I use will always display it (even if the rest of the message gets cut off).