sl: brew uninstall sl produces misleading warning about openssl

[woodruffw]

brew gist-logs <formula> link OR brew config AND brew doctor output

$ brew config
HOMEBREW_VERSION: 4.3.9-265-g75e77db
ORIGIN: https://github.com/Homebrew/brew
HEAD: 75e77db9f4c5b0760d464722a3298f44785c8dc2
Last commit: 57 minutes ago
Core tap HEAD: 4f7989feaa16e0f1987a1abc6614967f0f9e32d8
Core tap last commit: 25 hours ago
Core tap JSON: 15 Jul 20:59 UTC
Core cask tap JSON: 15 Jul 20:59 UTC
HOMEBREW_PREFIX: /opt/homebrew
HOMEBREW_CASK_OPTS: []
HOMEBREW_MAKE_JOBS: 10
HOMEBREW_SORBET_RUNTIME: set
Homebrew Ruby: 3.3.4 => /opt/homebrew/Library/Homebrew/vendor/portable-ruby/3.3.4/bin/ruby
CPU: 10-core 64-bit arm_firestorm_icestorm
Clang: 15.0.0 build 1500
Git: 2.44.0 => /opt/homebrew/bin/git
Curl: 8.6.0 => /usr/bin/curl
macOS: 14.5-arm64
CLT: 15.3.0.0.1.1708646388
Xcode: N/A
Rosetta 2: false

$ brew doctor
Your system is ready to brew.

Verification

• My brew doctor output says Your system is ready to brew. and am still able to reproduce my issue.
• I ran brew update and am still able to reproduce my issue.
• I have resolved all warnings from brew doctor and that did not fix my problem.
• I searched for recent similar issues at https://github.com/Homebrew/homebrew-core/issues?q=is%3Aissue and found no duplicates.

What were you trying to do (and why)?

I was trying to show sl (a very important program) to @Moisan and then uninstall it afterwards.

What happened (include all command output)?

$ brew uninstall sl
Uninstalling /opt/homebrew/Cellar/sl/5.02... (7 files, 40.0KB)

Warning: The following may be sl configuration files and have not been removed!
If desired, remove them manually with `rm -rf`:
  /opt/homebrew/etc/[email protected]
  /opt/homebrew/etc/openssl@3

What did you expect to happen?

The above, but with no misleading warning about deleting openssl's configurations.

Step-by-step reproduction instructions (by running brew commands)

brew install sl
brew uninstall sl

[Bo98]

The word "may" is because the check for this is rudimentary: https://github.com/Homebrew/brew/blob/75e77db9f4c5b0760d464722a3298f44785c8dc2/Library/Homebrew/uninstall.rb#L69-L72. Not all formulae use the pkgetc system.

[cho-m]

It does seem a bit risky to recommend rm -rf-ing directories which some users may blindly run and break functionality.

We could track etc files that are included inside bottle with some extra record keeping. Though there isn't a great way to track all etc files as some are created at runtime (may need something more manual like Casks).

[cho-m]

One idea is Homebrew/brew#18570; however, it only shows build-time installed configuration files and won't be able to detect generated files.

Could still keep guesses but I've seen user issues where the root cause was removing some etc file so recommending poor guesses is risky, even with additional warnings.

There doesn't seem to be an ideal option for generated files.

• Using Cask zap style lists would probably be safest option but have higher maintenance overhead.
• Perhaps there is an external source of common config file names that we could use.
• Making the regex stricter/smarter may help but would need to verify how accurate and number of false positives

On formula side, we could try moving as much etc usage to pkgetc; however, this would be a breaking change.