Error: operation is already in progress for apr

[treellama]

Trying to brew install subversion results in this error:

Error: Operation already in progress for apr
Another active Homebrew process is already using apr.
Please wait for it to finish or terminate it to continue.

But no Homebrew processes are running. /Library/Caches/Homebrew/Formula is also starting to fill up with *.brewing files. Removing all of them and trying to brew install subversion results in *.brewing files for all dependencies showing up again.

Removing apr doesn't change the error while installing subversion. I can reinstall apr just fine.

I was able to install zile successfully today, with its two dependencies, so it doesn't happen for all formulae. I tried installing autoconf, which also depends on a tap in homebrew/dupes, and it started to download m4 just fine. There is even an m4.brewing in /Library/Caches/Homebrew/Formula but it doesn't raise an error.

[mistydemeo]

I've fixed this bug in eace716. Sorry about that!

It turns out that the new build lock feature in homebrew depends on a feature which is unavailable in the very old version of ruby that comes with Tiger. In the short term I've simply made it a no-op; in the future I'll look at backporting the flock feature itself.