mono package no longer installs msbuild

[yeurch]

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

➜  ~ brew config
HOMEBREW_VERSION: 4.4.6
ORIGIN: https://github.com/Homebrew/brew
HEAD: cc0b5d6d05d1f3af5b2f53e9fbb1e7bfa0c332ab
Last commit: 5 days ago
Core tap JSON: 20 Nov 16:49 UTC
Core cask tap JSON: 20 Nov 16:49 UTC
HOMEBREW_PREFIX: /opt/homebrew
HOMEBREW_CASK_OPTS: []
HOMEBREW_MAKE_JOBS: 12
Homebrew Ruby: 3.3.6 => /opt/homebrew/Library/Homebrew/vendor/portable-ruby/3.3.6/bin/ruby
CPU: dodeca-core 64-bit dunno
Clang: 16.0.0 build 1600
Git: 2.39.5 => /Library/Developer/CommandLineTools/usr/bin/git
Curl: 8.7.1 => /usr/bin/curl
macOS: 15.1.1-arm64
CLT: 16.1.0.0.1.1729049160
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)?

After installing the mono package, I was trying to build a third party project that requires mono and msbuild in order to build. My expectation was that the mono package would also install msbuild, because that's what the official mono installer does.

What happened (include all command output)?

Instead, I encountered a build failure when building the third party project because the Homebrew mono package no longer includes msbuild.

What did you expect to happen?

As per previously resolved issue #29420, "msbuild" is a critical tool for use of modern C#. It is normally found distributed with either the Mono or .NET Core packages.

As such, and in common with the official mono installer from mono-project.com, I'd expect msbuild to be available after installing the mono package.

As a result of issue #29420, support for msbuild was added with PR #29422.

However, it was removed in PR #166109 with this comment stating that it was removed because it was only a dependency of the removed f-sharp executable. However, as several issues have mentioned before, msbuild is shipped with mono and is an essential part of .NET development, so it likely shouldn't have been removed.

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

1. > brew install mono
2. > which msbuild
Results in a message: `msbuild not found`

[cho-m]

You should install the Cask mono-mdk if you want the official mono installer.

MSBuild does not compile on native ARM macOS (which you are on based on brew config) so it was never provided as part of Formula mono.

Upstream needed to re-sync with .NET MSBuild but never got around to it mono/msbuild#435. Upstream is now undergoing some migration to ownership by WineHQ so no idea what is state of project.

For most part, mono formula is only still around for the runtime to be used by dependents (e.g. nuget, paket, etc.). The upstream packaging scripts don't work on ARM macOS and Linux.

Only Intel macOS may still be able to ship everything, but that won't help for your system (unless installing Rosetta, though might as well use Cask instead)

[yeurch]

Got it, thanks for the detailed response and explanation. That all makes total sense.