On Dart rolls, git commands executed during the build and during the initial checkout appear to be failing to hit the git cache on the bots sometimes. Like in https://ci.chromium.org/ui/p/flutter/builders/try/Mac%20Engine%20Drone/138201/overview.

error: unable to normalize alternate object path: /Volumes/Work/s/w5zm283yk/ir/cache/git/dart.googlesource.com-sdk/objects

This is manifesting as a failure when extra output from the error messages is polluting Dart's version.cc file, which causes the build to fail, but the error is also printed during the initial checkout:

https://logs.chromium.org/logs/flutter/buildbucket/cr-buildbucket/8785725138688366817/+/u/Checkout_source_code/bot_update/stdout?format=raw

Filing under infra since it seems like this might be a problem with the git caching setup on the bots.

cc @rmacnak-google to take a look at the git commands in Dart's make_version.py.