chintan

Yesterday, I re-installed my homebrew install because it was corrupted. That led to a huge headache where I couldn’t install any gems with native extensions. It took forever for me to find the issue, so I thought I’d write this in the hopes it helps anyone googling around.

My issue was that I’d installed gcc-4.2 using homebrew. Re-installing homebrew broke that install.

Solution:

First, try brew install apple-gcc42. If you’re lucky, it’ll work, and you’re set.

If not, you need to tap homebrew/dupes. A tap is just homebrew speak for another git repository with extra formulae. Try

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brew tap homebrew/dupes
brew update
brew install apple-gcc42

It might fail on the brew update step. This is a super old bug that’s been fixed, but you need to do the following:

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cd $(brew --repository)
git reset --hard FETCH_HEAD

If that doesn’t work:

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cd $(brew --repository)/Library
git clean -fd

Now that almost fixed it for me, but when I ran brew update it was complaining about overwritten files in homebrew/dupes. I couldn’t find the solution for this anywhere, so I kept poking around and trying different things. Here’s what worked:

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cd $(brew --repository)/Library/Taps/homebrew-dupes
git reset --hard FETCH_HEAD
brew update
brew tap --repair homebrew/dupes

And now, you should be able to brew install apple-gcc42 and your native extensions should install. It’s worth noting that you need gcc-4.2 for the native extensions. Using another version of gcc (4.3 – 4.8) won’t work.

Happy hacking!