In do_validate_kernel there is a test for whether the machine_branch exists. The test is whether the return value of git show-ref --verify is exactly one. At least on my machine the return value is 128 when the branch does not exist. Maybe the test should be whether the return value is not 0?
Bruce, this looks like a valid report to me. Giving this one to you for the tooling.
No we really want to check for 1: --verify Enable stricter reference checking by requiring an exact ref path. Aside from returning an error code of 1, it will also print an error message if --quiet was not specified. We can't target all versions of git at once, so I'm continuing to go with the man page and recent sources.
I should add that if we can show a real tree, where this fails, and either a cryptic error message comes out, or another check doesn't catch the problem later, I'll revisit.