Possible bug in git describe, additional commits differs when cloned with --depth

[Anders Janmyr <anders@janmyr.com>]

Hi,

I'm not sure if this is a bug or not but `git describe` gives
different results when the repo has been cloned with `--depth` or not.

In the example below from the git repository the number of additional
commits since the
last tag differs 256 vs. 265.

```
$ git clone https://github.com/git/git
$ cd git/
$ git describe
v2.23.0-256-g4c86140027
$ git rev-list -n 1 HEAD
4c86140027f4a0d2caaa3ab4bd8bfc5ce3c11c8a


$ git clone --depth=50 https://github.com/git/git git-depth
$ cd git-depth/
$ git describe
v2.23.0-265-g4c861400
$ git rev-list -n 1 HEAD
4c86140027f4a0d2caaa3ab4bd8bfc5ce3c11c8a
```

In the example above the first version also gives additional digits
for the SHA,
g4c86140027 vs. g4c861400, but that is not always the case.

I came upon this discrepancy when using the value from `git describe`
in a build pipeline
where the system optimized the build by cloning the repo using `--depth`.

Kind regards
--
http://anders.janmyr.com/
@andersjanmyr
+46 733-99 03 60