Add a default soundfont file at fluidsynth install

[e-dervieux]

Output of brew config

HOMEBREW_VERSION: 4.5.13
ORIGIN: https://github.com/Homebrew/brew
HEAD: 4d14be89e99a45181c18e96a5f19a5b43343cc0f
Last commit: 5 days ago
Branch: stable
Core tap JSON: 30 Jul 11:41 UTC
Core cask tap JSON: 30 Jul 11:41 UTC
HOMEBREW_PREFIX: /opt/homebrew
HOMEBREW_CASK_OPTS: []
HOMEBREW_DISPLAY: /private/tmp/com.apple.launchd.e0GhQE9ehG/org.xquartz:0
HOMEBREW_EDITOR: /usr/bin/nano
HOMEBREW_MAKE_JOBS: 10
HOMEBREW_SORBET_RUNTIME: set
Homebrew Ruby: 3.4.5 => /opt/homebrew/Library/Homebrew/vendor/portable-ruby/3.4.5/bin/ruby
CPU: deca-core 64-bit arm_blizzard_avalanche
Clang: 17.0.0 build 1700
Git: 2.50.1 => /opt/homebrew/bin/git
Curl: 8.7.1 => /usr/bin/curl
macOS: 15.5-arm64
CLT: 16.4.0.0.1.1747106510
Xcode: N/A
Rosetta 2: false

Output of brew doctor

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: No Cask quarantine support available: unknown reason.

Warning: The following formulae have the same name as core formulae:
  homebrew-ffmpeg/ffmpeg/ffmpeg
Some of these can be resolved with:
  brew untap homebrew-ffmpeg/ffmpeg

Description of issue

When installing fluidsynth using this formula, everything works well, except no default soundfont is installed.

This is problematic because fluidsynth expects one and the software is basically unusable without it:

$ fluidsynth
FluidSynth runtime version 2.4.7
Copyright (C) 2000-2025 Peter Hanappe and others.
Distributed under the LGPL license.
SoundFont(R) is a registered trademark of Creative Technology Ltd.

fluidsynth: error: fluid_sfloader_load(): Failed to open '/opt/homebrew/Cellar/fluid-synth/2.4.7/share/soundfonts/default.sf2': File does not exist.
fluidsynth: error: Unable to open file '/opt/homebrew/Cellar/fluid-synth/2.4.7/share/soundfonts/default.sf2'
fluidsynth: error: Failed to load SoundFont "/opt/homebrew/Cellar/fluid-synth/2.4.7/share/soundfonts/default.sf2"
Type 'help' for help topics.

> 

This is not a fluidsynth issue according to one of their lead dev, who considers that providing a soundfont with fluidsynth install is the responsability of the package manager (see here and there), in this case: homebrew.

There are plenty of GPL / MIT / CC license to chose from here. I would advise for the GeneralUser GS one, which is quite complete.

Of note, I did notice that the formula contains a test which uses a Drum soundfont from the fluidsynth repository, but this is of course insufficient for any use whatsoever.

---

Note: I would have created a proper issue for this, but my brew doctor is not perfectly clean and I did not want to be banished into oblivion for such a trifle (all the more because the Warnings that I get have no relation to the issue at hand). If someone out there thinks it's OK to turn this into a full-fledge issue, I'd be happy to create one.

[p-linnane]

A pull request in Homebrew/core making the changes you'd like to see (including updating the test to be more robust) would be very appreciated.

[e-dervieux]

Haha ^^

To be honest, despite having been using it for a several years, I'm a complete newbie regarding the inner mechanics of Homebrew and its formulae. Still, I'll try to have a look into this if I can find some time in the upcoming weeks. I'll reach back here if I run into some difficulties...