[clang-tools-extra] [clang-tidy] Header check support for check_clang_tidy.py (PR #175735)

[Nico Weber via cfe-commits]

nico wrote:

Hi, one of the tests in here fails on my bot: http://45.33.8.238/linux/190117/step_7.txt

That bot is a bit weird in that it uses an unsupported build system, so this might be due to bot weirdness. But maybe the error message makes sense to you? Are we maybe iterating something (dict keys or what) in non-deterministic order or similar?

https://github.com/llvm/llvm-project/pull/175735