Upgrading to Catalina was an overall painless process. The main issue I ran into after upgrading was with compiling packages. I’ve previously had issues with installing specific packages via homebrew, as well as certain gems(such as llvm, or nokogiri).

Previous Solution

Previously to get things to compile I would install OSX header files via running

open /Library/Developer/CommandLineTools/Packages/macOS_SDK_headers_for_macOS_10.14.pkg

However, with Xcode 11, and Catalina, that file no longer exists.

Current solution

updated 10-24-2019 After upgrading to Catalina, I needed to

  1. Open Xcode and let it install “Additional Components”
  2. Rerun xcode-select --install from the terminal
  3. Ensure only one version of llvm is installed via brew
  4. Add export SDKROOT="/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk" to ~/.bash_profile

Previously I also had added export CPATH="/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include" but that doesn’t seem to be required anymore.

once that was done, brew packages, and gem installs(gem install nokogiri is always a good test) compiled and installed correctly!