mxcl/homebrew — comment on commit 2eabe2cbc84649696aeb6fa842a70f3794955597
File:  line 0
By jacknagel:

So here's steps to reproduce Mike's bug:

* Have two versions of a formula installed, say pcre 8.20 and 8.21, with 8.21 linked.
* `cd $(brew --cellar pcre); rm -rf 8.21`
* brew install -v pcre

And the _real_ problem:

```
raise "Cannot link #{fname}\nAnother version is already linked: #{linked_keg_record.realpath}" if linked_keg_record.directory?
```

is tripped, even though the (temporarily broken) symlink in LinkedKegs points at the keg we *just installed*.