Git minimum version check

[shorebvba]

It might be a good idea to specify the minimum Git version, as currently you get misleading errors when using 1.8 for example, which does not have the -C option apparently.
Checking version before using -C in versioningit code would be ideal, but in the readme would also suffice i guess.

If this is a pebcac, i apologize, if not i'm willing to contribute.

[jwodder]

So here are all of the Git features that versioningit uses, in no particular order, (not counting $Format:%(describe)$, which it doesn't use directly) and the Git versions that introduced them:

• git -C <dir> option — added in Git 1.8.5
• git --no-pager option — added in Git 1.5.3
• git rev-parse --is-inside-work-tree — added in Git 1.5.3
• git ls-files --error-unmatch . — added in (or at least existed in) Git 1.3.0
• git describe:
  • The output only started including the distance in Git 1.5.0.
  • --tags option — existed in Git 1.1.0
  • --long option — added in Git 1.5.5
  • --dirty option — added in Git 1.6.6
  • --always option — added in (or at least existed in) Git 1.5.6
  • --match option — added in Git 1.5.5; support for specifying multiples times added in Git 2.13.0
  • --exclude option — added in Git 2.13.0
• git symbolic-ref --short -q HEAD — fully implemented in Git 1.7.10
• git show:
  • -s option — existed prior to Git 1.0
  • --format option — added in Git 1.6.3
  • %H, %n, %at, and %ct format placeholders — all added in Git 1.5.1
• git rev-list --count HEAD — added in Git 1.7.2

Aside from --match and --exclude (which are only used if the user requests them), the most recent feature here is the -C option, which is easy to compensate for. The next most recent is git symbolic-ref --short -q HEAD (used to determine the branch name), which I am not aware of a decent older alternative for.

So, assuming I can spin up a Docker container with Git 1.8.0 and a recent Python and get versioningit's non-match/exclude tests to pass in it, I can then make a new release that doesn't use the -C option, and I will document 1.8.0 as the minimum required Git version in the README.

I'd rather not introduce an explicit Git version check into the code; there are already concerns about the Git calls taking up too much time, and I expect there to be very few users using an over-ten-years-old version of Git (especially considering that versioningit currently doesn't support any Python versions more than six years old).

[shorebvba]

Wow, for me this post alone helps a lot. Thank you!
We are currently stuck with 1.8.3.1 on a CentOS server. So not the end of the world (yet, hehe).
I didn't realize the speed hit on git calls.

Great work! Thank you.

[jwodder]

Update: versioningit v0.3.3 is now out with support for Git 1.8.0.

[shorebvba]

wow, amazing speed John, thank you so much
will try this week

[shorebvba]

fixed our issues, working on upgrading git anyway

A+++ service, would recommend :)