Brew: What does "You may now chown /usr/local back to root:wheel" and what should I do?

[KMamedoff]

It is shown after I updated Homebrew.

[zmwangx]

Well, exactly as said "you may now chown /usr/local back to root:wheel".

[zmwangx]

Congratulations on a successful migration.

[KMamedoff]

Yes but I don't know how to do that.

[zmwangx]

sudo chown root:wheel /usr/local

You don't have to do that though, it just doesn't matter anymore.

[KMamedoff]

I did it anyway. Thank you.

[pbregener]

I just got the same message. While I do know how to do it, it'd like to know why. Was the owner changed in the migration process? And as it says "may", I assume it's not necessary?

[pbregener]

Thanks @zmwangx. Can you provide some more background? Why is that message shown and why is it so ambiguous?

[zmwangx]

@pbregener Homebrew used to require writing access to /usr/local. Now it no longer writes to /usr/local, only subdirectories of /usr/local.

Was the owner changed in the migration process?

No, but Apple likes seeing /usr/local being owned by root:wheel, and major macOS upgrades do that.

And as it says "may", I assume it's not necessary?

It's not.

[pbregener]

Thanks for the quick reply and good and short explanation @zmwangx 👍

[MikeMcQuaid]

Improved this message in https://github.com/Homebrew/brew/commit/a2f19f0a675f7cb384b48bad773d31366c6b258d

[kevwil]

Would it be accurate to say the user still needs to own some/most/all folders under /usr/local? I'm just curious what the "correct" permission set looks like, if such a perspective even exists.

[MikeMcQuaid]

@kevwil Yep. Those folders are checked for you though (and not reset by Apple on updates).

[dmofot]

Just throwing this here in case somebody else runs into the issue. I ran sudo chown root:wheel #{HOMEBREW_PREFIX} and everything appeared fine. Then ran brew cask list which returned

$ brew cask list
==> Moving Caskroom from HOMEBREW_REPOSITORY to HOMEBREW_PREFIX
Error: Permission denied - (/usr/local/Homebrew/Caskroom, /usr/local/Caskroom)Most likely, this means you have an outdated version of Homebrew-Cask. Please run:

    brew uninstall --force brew-cask; brew untap phinze/cask; brew untap caskroom/cask; brew update; brew cleanup; brew cask cleanup

If this doesn’t fix the problem, please report this bug:

    https://github.com/caskroom/homebrew-cask#reporting-bugs

/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/fileutils.rb:519:in `rename'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/fileutils.rb:519:in `block in mv'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/fileutils.rb:1558:in `block in fu_each_src_dest'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/fileutils.rb:1574:in `fu_each_src_dest0'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/fileutils.rb:1556:in `fu_each_src_dest'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/fileutils.rb:508:in `mv'
/usr/local/Homebrew/Library/Homebrew/cask/lib/hbc/caskroom.rb:8:in `migrate_caskroom_from_repo_to_prefix'
/usr/local/Homebrew/Library/Homebrew/cask/lib/hbc.rb:52:in `init'
/usr/local/Homebrew/Library/Homebrew/cask/lib/hbc/cli.rb:146:in `process'
/usr/local/Homebrew/Library/Homebrew/cask/cmd/brew-cask.rb:8:in `<top (required)>'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
/usr/local/Homebrew/Library/Homebrew/brew.rb:23:in `require?'
/usr/local/Homebrew/Library/Homebrew/brew.rb:105:in `<main>'

Needed to run sudo brew cask list due to the new permissions:

$ sudo brew cask list
Password:
==> Moving Caskroom from HOMEBREW_REPOSITORY to HOMEBREW_PREFIX

And now everything works fine without having to resort to sudo again.

[hmijail]

This was messy and is getting messier. Maybe it would be good if the Homebrew devs published a FAQ: "up to version X we did this because of blah1, but since version Y the recommended practice is Z, because of blah2".

[MikeMcQuaid]

@hmijail We'll consider that in future but not at present.