Docker for Mac - mkmf.rb can't find header files for ruby

Question

I updated XCode on my Mac and since then when starting Docker using docker-sync-stack start I get this error message:

mkmf.rb can\'t find header         


        

Answer 1

As of Xcode 11, it seems like the ruby development headers are no longer included, so you will need to manually install them outside of Xcode Command Line Tools.

E.g. for me using rbenv i did

rbenv install 2.6.4
rbenv global 2.6.4
eval "$(rbenv init -)"

Then ran bundle install and everything worked as expected.