brew audit throwing undefined method 'path' error

[lockefox]

Github is throwing HTTP400 errors when I try to submit an issue to https://github.com/Homebrew/brew/issues

I am following the steps set out by https://docs.brew.sh/Python-for-Formula-Authors
I cannot use brew update-python-resources due to private PyPI dependencies.
I am trying to fix some failing tests on https://github.com/tdsmith/homebrew-pypi-poet
Was able to run the brew audit --strict <recipe> validators last night before 3ab140e39753536b7e6f8ce337f6f000e31cbb2f #12470 release
working on PR: tdsmith/homebrew-pypi-poet#71

$> pip3 install homebrew-pypi-poet
$> poet -f pytest > pytest.rb
$> brew audit --strict pytest.rb
Error: Failed to load cask: pytest.rb
Cask 'pytest' is unreadable: wrong constant name #<Class:0x00007ff7b29c5520>
Warning: Treating pytest.rb as a formula.
Error: undefined method `path' for nil:NilClass
Did you mean?  paths
Please report this issue:
  https://docs.brew.sh/Troubleshooting
/usr/local/Homebrew/Library/Homebrew/formula_auditor.rb:124:in `audit_synced_versions_formulae'
/usr/local/Homebrew/Library/Homebrew/formula_auditor.rb:823:in `block in audit'
/usr/local/Homebrew/Library/Homebrew/formula_auditor.rb:818:in `each'
/usr/local/Homebrew/Library/Homebrew/formula_auditor.rb:818:in `audit'
/usr/local/Homebrew/Library/Homebrew/dev-cmd/audit.rb:185:in `block in audit'
/usr/local/Homebrew/Library/Homebrew/dev-cmd/audit.rb:169:in `map'
/usr/local/Homebrew/Library/Homebrew/dev-cmd/audit.rb:169:in `audit

Same issue happens for brew audit --new-formula
Also happening on travis xcode13.1: https://app.travis-ci.com/github/tdsmith/homebrew-pypi-poet/jobs/549536315

Expected output:

$> pip3 install homebrew-pypi-poet
$> poet -f pytest > pytest.rb
$> brew audit --strict pytest.rb
  * 1: col 1: No Sorbet sigil found in file. Try a `typed: false` to start (you can also use `rubocop -a` to automatically add this).
  * 1: col 1: Missing top-level documentation comment for `class Pytest`.
  * 1: col 1: Missing frozen string literal comment.

current version of poet fails lint checks

---

$> brew config
HOMEBREW_VERSION: 3.3.5-28-g3ab140e
ORIGIN: https://github.com/Homebrew/brew
HEAD: 3ab140e39753536b7e6f8ce337f6f000e31cbb2f
Last commit: 9 hours ago
Core tap ORIGIN: https://github.com/Homebrew/homebrew-core
Core tap HEAD: 275a26f6ff36d452f60295b091f2bea4756e44c8
Core tap last commit: 14 minutes ago
Core tap branch: master
HOMEBREW_PREFIX: /usr/local
HOMEBREW_CASK_OPTS: []
HOMEBREW_CORE_GIT_REMOTE: https://github.com/Homebrew/homebrew-core
HOMEBREW_MAKE_JOBS: 16
Homebrew Ruby: 2.6.8 => /usr/local/Homebrew/Library/Homebrew/vendor/portable-ruby/2.6.8/bin/ruby
CPU: 16-core 64-bit kabylake
Clang: 13.0.0 build 1300
Git: 2.30.1 => /Library/Developer/CommandLineTools/usr/bin/git
Curl: 7.64.1 => /usr/bin/curl
macOS: 11.6-x86_64
CLT: 13.0.0.0.1.1630607135
Xcode: 13.1

$> brew doctor
Your system is ready to brew.

Reproduction steps:

brew update
brew ls python3 || brew install python
python3 -m pip install homebrew-pypi-poet
poet -f pytest > pytest.rb
brew audit --strict pytest.rb

[carlocab]

brew audit doesn't work on arbitrary formula files. It needs to be installed in a tap to work. For example:

❯ poet -f pytest > "$(brew --repository homebrew/core)/Formula/pytest.rb"
❯ brew audit --strict pytest
pytest:
  * Dependency 'python3' is an alias; use the canonical name 'python@3.9'.
Error: 1 problem in 1 formula detected

Incidentally, your expected output is actually not expected at all. Those errors should never show up for formulae.

[lockefox]

Trying to fix: https://github.com/tdsmith/homebrew-pypi-poet/blob/master/poet/test/test_poet.py#L49

When I ran yesterday, I had the lint issues described. Installing a debug recipe into host formulas seems like a dangerous/unstable pattern.

If install to core is required, should this doc get an update? https://docs.brew.sh/Formula-Cookbook#audit-the-formula

[carlocab]

Installation into core is not required. Installation into a tap is. You are free to install it into your own tap.

❯ poet -f pytest > "$(brew --repository carlocab/personal)/Formula/pytest.rb"
❯ brew audit --strict pytest

should this doc get an update?

Which part needs updating? It looks fine to me. We're always happy to make the documentation clearer, though.