Fetch, install, etc. use the full path to the formula file as an argument to brew, but unpack is run by the sentinel after brew fetch completes so it has to parse the process name, which doesn't have the full path: https://github.com/dunn/homebrew-mode/blob/master/homebrew-mode.el#L223
As a result if you try to unpack a formula in a tap, and the formula shares a name with something in core, you'll unpack the core formula instead.
Fetch, install, etc. use the full path to the formula file as an argument to
brew, but unpack is run by the sentinel afterbrew fetchcompletes so it has to parse the process name, which doesn't have the full path: https://github.com/dunn/homebrew-mode/blob/master/homebrew-mode.el#L223As a result if you try to unpack a formula in a tap, and the formula shares a name with something in core, you'll unpack the core formula instead.