brew update displays external diff tool

[cmumford]

brew doctor output

Please note that these warnings are just used to help the Homebrew maintainers
with debugging if you file an issue. If everything you use Homebrew for is
working fine: please don't worry or file an issue; just ignore this. Thanks!

Warning: Unbrewed dylibs were found in /usr/local/lib.
If you didn't put them there on purpose they could cause problems when
building Homebrew formulae, and may need to be deleted.

Unexpected dylibs:
  /usr/local/lib/libfido2.1.12.0.dylib
  /usr/local/lib/libusb-1.0.0.dylib
  /usr/local/lib/libusb-1.0.dylib

Warning: Unbrewed header files were found in /usr/local/include.
If you didn't put them there on purpose they could cause problems when
building Homebrew formulae, and may need to be deleted.

Unexpected header files:
  /usr/local/include/fido.h
  /usr/local/include/fido/bio.h
  /usr/local/include/fido/config.h
  /usr/local/include/fido/credman.h
  /usr/local/include/fido/eddsa.h
  /usr/local/include/fido/err.h
  /usr/local/include/fido/es256.h
  /usr/local/include/fido/es384.h
  /usr/local/include/fido/param.h
  /usr/local/include/fido/rs256.h
  /usr/local/include/fido/types.h

Warning: Unbrewed '.pc' files were found in /usr/local/lib/pkgconfig.
If you didn't put them there on purpose they could cause problems when
building Homebrew formulae, and may need to be deleted.

Unexpected '.pc' files:
  /usr/local/lib/pkgconfig/libfido2.pc

Warning: You have unlinked kegs in your Cellar.
Leaving kegs unlinked can lead to build-trouble and cause formulae that depend on
those kegs to fail to run properly once built. Run `brew link` on these:
  autopep8
  pyyaml

Warning: You have an unnecessary local Cask tap.
This can cause problems installing up-to-date casks.
Please remove it by running:
  brew untap homebrew/cask

Warning: You have an unnecessary local Core tap!
This can cause problems installing up-to-date formulae.
Please remove it by running:
 brew untap homebrew/core

Warning: Your Xcode (14.2) is outdated.
Please update to Xcode 14.3 (or delete it).
Xcode can be updated from the App Store.


Warning: Broken symlinks were found. Remove them with `brew cleanup`:
  /opt/homebrew/opt/[email protected]

Verification

• My "brew doctor output" above says Your system is ready to brew. and am still able to reproduce my issue.
• I ran brew update twice and am still able to reproduce my issue.
• This issue's title and/or description do not reference a single formula e.g. brew install wget. If they do, open an issue at https://github.com/Homebrew/homebrew-core/issues/new/choose instead.

brew config output

HOMEBREW_VERSION: 4.0.16
ORIGIN: https://github.com/Homebrew/brew
HEAD: 01e0c20d01c6aab28d844280d130f0e745e2ddd9
Last commit: 3 days ago
Core tap origin: https://github.com/Homebrew/homebrew-core
Core tap HEAD: 16ecf1ffb549e0903b533507c0dcba23d520c93c
Core tap last commit: 9 weeks ago
Core tap branch: master
Core tap JSON: 03 May 11:33 UTC
HOMEBREW_PREFIX: /opt/homebrew
HOMEBREW_CASK_OPTS: []
HOMEBREW_EDITOR: vim
HOMEBREW_MAKE_JOBS: 10
Homebrew Ruby: 2.6.10 => /System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/bin/ruby
CPU: 10-core 64-bit arm_firestorm_icestorm
Clang: 14.0.0 build 1400
Git: 2.40.1 => /opt/homebrew/bin/git
Curl: 7.87.0 => /usr/bin/curl
macOS: 13.3.1-arm64
CLT: 14.3.0.0.1.1679647830
Xcode: 14.2
Rosetta 2: false

What were you trying to do (and why)?

Update installed applications for security fixes/etc.

What happened (include all command output)?

When running brew update my configured external Git diff tool (meld) opened and displayed a diff of packages (casks?)

I believe it succeeded.

What did you expect to happen?

Meld would not be opened.

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

My [~/.gitconfig](https://github.com/cmumford/cmumfordenv/blob/master/home/.gitconfig) file contains the following:


[diff]
  external = $HOME/bin/gitdiff.py
  renames = true
  renameLimit = 999999

If I rename [diff] to [diffXXX] section it meld (via gitdiff.py) will not be opened.

I believe the solution is that when meld executes git diff it needs to add the --no-ext-diff argument.