A recent(-ish) change in git [1] has exposed a bug in caching that
appears in one very specific circumstance -- updating the
openstack/openstack super-repo [2].
This repo gets a submodule update every time something is pushed. By
using "--git-dir" while the cwd is one-level above the actual repo we
are confusing [1] which is not finding the submodule directories
correctly and giving us an error:
Could not access submodule 'foo'
for every submodule that has updated between now and the last time we
updated the cache. [3]
The git manual does warn about this
If you just want to run git as if it was started in <path> then use
git -C <path>.
Indeed, that is what we want to do in this path. Modify the calls to
use -C.
[1] 505a276596
[2] https://opendev.org/openstack/openstack/
[3] The result for opendev production is that image builds fail every
time an openstack/* project is checked in; we then race to retry
the build before another commit lands and updates the submodules
again.
Change-Id: Iadb23454e29d8869e11407e1592007b0f0963e17
ddb06b6657