brew cleanup should continue even if it wasn't permitted to remove a file

[andreasabel]

Provide a detailed description of the proposed feature

Current situation:

$ brew cleanup --debug
...
Removing: /usr/local/Cellar/icu4c/67.1... (258 files, 71MB)
Error: Directory not empty @ dir_s_rmdir - /usr/local/Cellar/icu4c/67.1

/usr/local/Homebrew/Library/Homebrew/vendor/portable-ruby/2.6.3_2/lib/ruby/2.6.0/fileutils.rb:1431:in `rmdir'
/usr/local/Homebrew/Library/Homebrew/vendor/portable-ruby/2.6.3_2/lib/ruby/2.6.0/fileutils.rb:1431:in `block in remove_dir1'
/usr/local/Homebrew/Library/Homebrew/vendor/portable-ruby/2.6.3_2/lib/ruby/2.6.0/fileutils.rb:1442:in `platform_support'
/usr/local/Homebrew/Library/Homebrew/vendor/portable-ruby/2.6.3_2/lib/ruby/2.6.0/fileutils.rb:1430:in `remove_dir1'
/usr/local/Homebrew/Library/Homebrew/vendor/portable-ruby/2.6.3_2/lib/ruby/2.6.0/fileutils.rb:1423:in `remove'
/usr/local/Homebrew/Library/Homebrew/vendor/portable-ruby/2.6.3_2/lib/ruby/2.6.0/fileutils.rb:760:in `block in remove_entry'
/usr/local/Homebrew/Library/Homebrew/vendor/portable-ruby/2.6.3_2/lib/ruby/2.6.0/fileutils.rb:1480:in `ensure in postorder_traverse'
/usr/local/Homebrew/Library/Homebrew/vendor/portable-ruby/2.6.3_2/lib/ruby/2.6.0/fileutils.rb:1480:in `postorder_traverse'
/usr/local/Homebrew/Library/Homebrew/vendor/portable-ruby/2.6.3_2/lib/ruby/2.6.0/fileutils.rb:758:in `remove_entry'
/usr/local/Homebrew/Library/Homebrew/vendor/portable-ruby/2.6.3_2/lib/ruby/2.6.0/fileutils.rb:610:in `block in rm_r'
/usr/local/Homebrew/Library/Homebrew/vendor/portable-ruby/2.6.3_2/lib/ruby/2.6.0/fileutils.rb:606:in `each'
/usr/local/Homebrew/Library/Homebrew/vendor/portable-ruby/2.6.3_2/lib/ruby/2.6.0/fileutils.rb:606:in `rm_r'
/usr/local/Homebrew/Library/Homebrew/vendor/portable-ruby/2.6.3_2/lib/ruby/2.6.0/pathname.rb:589:in `rmtree'
/usr/local/Homebrew/Library/Homebrew/keg.rb:275:in `uninstall'
/usr/local/Homebrew/Library/Homebrew/cleanup.rb:252:in `block in cleanup_keg'
/usr/local/Homebrew/Library/Homebrew/cleanup.rb:338:in `cleanup_path'
/usr/local/Homebrew/Library/Homebrew/cleanup.rb:252:in `cleanup_keg'
/usr/local/Homebrew/Library/Homebrew/cleanup.rb:238:in `each'
/usr/local/Homebrew/Library/Homebrew/cleanup.rb:238:in `cleanup_formula'
/usr/local/Homebrew/Library/Homebrew/cleanup.rb:190:in `block in clean!'
/usr/local/Homebrew/Library/Homebrew/cleanup.rb:189:in `each'
/usr/local/Homebrew/Library/Homebrew/cleanup.rb:189:in `clean!'
/usr/local/Homebrew/Library/Homebrew/cmd/cleanup.rb:58:in `cleanup'
/usr/local/Homebrew/Library/Homebrew/brew.rb:129:in `<main>'

Atm, brew cleanup crashes instead of continuing to clean up.

Feature suggestion: ignore errors, or at least if a flag like --ignore-errors, -i is given.

What is the motivation for the feature?

There might be dynlibs I want to hang on so that upgrades do not remove them. After all, other programs (outside of the brew universe) have been linked against than and brew cleanup breaks them mercilessly. A simple workaround is to forbid brew to remove this files by making them read-only, but then brew cleanup crashes.

How will the feature be relevant to at least 90% of Homebrew users?

I suppose only 10% use brew exclusively for everything.

What alternatives to the feature have been considered?

N/A

[MikeMcQuaid]

Atm, brew cleanup crashes instead of continuing to clean up.

This is generally considered a bug rather than a feature. We try to catch the relevant exceptions and continue but this is imperfect.

There might be dynlibs I want to hang on so that upgrades do not remove them. After all, other programs (outside of the brew universe) have been linked against than and brew cleanup breaks them mercilessly. A simple workaround is to forbid brew to remove this files by making them read-only, but then brew cleanup crashes.

In this case, though, you should set HOMEBREW_NO_INSTALL_CLEANUP instead. It's expected that Homebrew trying to cleanup its own files failing because you've intentionally changed the permissions will error out.

[andreasabel]

In this case, though, you should set HOMEBREW_NO_INSTALL_CLEANUP instead.

No, don't get me wrong. I do want cleanup, I just want to hang on to certain files that have been linked to other executable.

Atm, brew cleanup crashes instead of continuing to clean up.

This is generally considered a bug rather than a feature.

I agree. Should I report it as bug instead?

[carlocab]

You can still pass a formula name to brew cleanup to clean up as specific formula. That's not exactly the behaviour that you want, but it's probably still better than trying to clean up the cellar manually.

That said, I do think allowing HOMEBREW_NO_INSTALL_CLEANUP to be set to a list of formulae you don't want to be cleaned up might be a nice feature. I don't have time to implement this, but I'd be happy to review a PR that does.

[MikeMcQuaid]

I agree. Should I report it as bug instead?

No, I've relabelled it but consider this to be working as desired.

No, don't get me wrong. I do want cleanup, I just want to hang on to certain files that have been linked to other executable.

That's not cleanup, as far as we're concerned.

[andreasabel]

I see.

Is there a workaround, like registering packages to brew that should not be cleaned up?
Very concretely, I want to keep old versions of icu4c (libraries) around.

[carlocab]

Is there a workaround, like registering packages to brew that should not be cleaned up?

Not currently. This is what my suggestion above would do:

That said, I do think allowing HOMEBREW_NO_INSTALL_CLEANUP to be set to a list of formulae you don't want to be cleaned up might be a nice feature

[MikeMcQuaid]

@andreasabel brew pin icu4c may do what you want.

[andreasabel]

@MikeMcQuaid: Thanks! This might last me a while, until some apps demand a newer version of icu4c.
A HOMEBREW_NO_CLEANUP=icu4c like in @carlocab's suggestion would take me all the way...

[carlocab]

It turns out this wasn't too hard, and when you've got an itch... #11931

[carlocab]

I've merged #11931. If you're on the brew master branch (e.g. if you're run a dev command -- see brew developer), then you should be able to do this with brew update. If not, you can wait until it lands on a release tag, or run brew developer on && brew update.

[andreasabel]

@carlocab Wonderful, that's great! I tried HOMEBREW_NO_CLEANUP_FORMULAE=icu4c with brew cleanup on the developer version and it did what I had wanted for a long time!

[carlocab]

HOMEBREW_NO_CLEANUP_FORMULAE is also in 3.2.11, so you don't need to be on the developer branch to use it.

Glad it's working for you.