I find `git describe` pretty human-usable. (I use it in a lot of automated processes.) You still need to tag every now and then, as the format is based on the most recent tag, but it tells you a bunch of useful information fairly compactly and almost semver compliant (in many cases you want to swap the first hyphen with a plus for true semver compliance if your tags are semver releases). It's format:

  {mostRecentAnnotatedTag}-{numberOfCommitsAfter}-g{headCommitShortHash}

Such as: v2.0.3-3-g1cafe9

That has enough information to get you back to exactly which branch was built (3 commits after v2.0.3 with a hash starting 1cafe9). Of course if you git describe when you've checked out the tagged commit itself you just get the tag back v2.0.3.

It's not as simple as simple "revision ID", but it is pretty simple.

In some of my CI pipelines I've been considering swapping my simple `git describe` tricks for `git-version` to make it easier to get more semver-like build metadata in order to CD them, but I've also considered just regexing that first hyphen to a plus and calling it a day.

My favorite is the complexity of having an in-tree changelog that lists (shortlog) commits under appropriate tag headings - checked in under appropriate tags.

It roughly amounts to:

1) commit fix (git commit -m "fixes #foo bug"

2) get hash/shortlog, add to changelog

3) commit changelog referencing commit in 1)

4) tag hash in 3) with new minor version 1.1.2 to 1.1.3

5) realize you forgot that 1) warranted a bump in minor version, edit changelog to reflect new minor version

6) commit new changelog

7) move tag from 4) to 6) - hope you didn't push yet...

And people say RCS $Id:$ was a hack...

Now,the real issue is actually to find a nice way to tag actual releases, with current tag and hash. I realize this is mostly tricky when a project is "checkout and run" - without a build step (eg ruby on rails project). It's still somewhat painful to make sure there's an up to date global variable that correctly reflects the running version.

I clone the project into a temp directory, then inject the version number into the source.