We have a `HOMEBREW_MACOS_NEWEST_UNSUPPORTED` environment variable
and this is used in `MacOSVersion` to determine prerelease versions
but we don't have a way of easily determining the newest supported
macOS version.
`bump-cask-pr` contains logic that assumes the first key/value in
`MacOSVersion::SYMBOLS` is the newest macOS version but it recently
became clear that this is a prerelease version between WWDC and the
subsequent macOS release. Similarly, `dev-cmd/generate-cask-api.rb`
tries to compute the newest stable macOS version as
`HOMEBREW_MACOS_NEWEST_UNSUPPORTED.to_i - 1` and this will fail
if/when we update that variable to `"26"`, as the macOS version
before 26 is 15, not 25.
This adds a `HOMEBREW_MACOS_NEWEST_SUPPORTED` environment variable,
so we have a straightforward way of quickly identifying the newest
supported macOS version without having to make potentially unreliable
assumptions or do computations to identify the latest non-prerelease
`MacOSVersion` value. This also updates the two aforementioned areas
to use this environment variable to produce the newest stable macOS
version symbol in a more reliable way.
While we're here, also add `brew tests --no-parallel` which I relied
on during testing.
Pretty much anywhere we rely on a stubbed formula on disk to work: we
need to disable the API.
Instead of repeatedly outputting the same identical messages across
multiple packages and repeating them all for every package after they
were all installed: just output the identical messages in the final
caveats output instead.
This was more painful that I expected but will allow `brew bundle sh`
and `brew sh` to use the user's configuration but use our custom prompt
for Bash and ZSH.
Add a new `brew mcp-server` command for a Model Context Protocol (MCP)
server for Homebrew. This integrates with AI/LLM tools like Claude,
Claude Code and Cursor.
It currently supports the calls needed/used by the MCP Inspector and
Cursor (where I've tested it).
It provides as `tools` the subcommands output by `brew help` but should
be fairly straightforward to add more in future.
It is implemented in a slightly strange way (a standalone Ruby command
called from a shell command) as MCP servers need a faster startup time
than a normal Homebrew Ruby command allows and fail if they don't get
it.
There are a few Ruby libraries available but, given how relatively
simplistic the implementation is, it didn't feel worthwhile to use and
vendor them.
