On my unsupported macOS (currently 10.14), whenever I brew upgrade, node breaks with the following error
$ node -v
dyld: Library not loaded: /usr/local/opt/icu4c/lib/libicui18n.69.dylib
Referenced from: /usr/local/opt/node@16/bin/node
Reason: image not found
If you ls in the /usr/local/opt/icu4c/lib/ directory, you'll see a different version, e.g. libicui18n.71.dylib or whatever.
I always fumble around trying to fix this, so here is what I think should be fairly stable instructions for how to resolve this issue.
Homebrew has a command to create a new tap (which is just a git repo) on your local machine. You need to give it a namespace, and a name.
$ brew tap-new namespace/name
Initialized empty Git repository in /usr/local/Homebrew/Library/Taps/namespace/name/.git/
Now, you'll be able to extract the old formula into this new tap.
In my example, I needed version 69.1 of icu4c. So my command was
$ brew extract --version=69.1 icu4c namespace/name
Swap namespace and name with whatever you picked before.
Now you have an .rb file that can install your version, but it probably won't link things correctly. That's OK, we'll be able to manually fix this later.
Run the reinstall command with your custom tap, the formula with version number, and the --build-from-source flag.
$ brew reinstall namespace/name/icu4c@69.1 --build-from-source
If that works, you should see a message similar to
icu4c@69.1 is keg-only, which means it was not symlinked into /usr/local,
because macOS provides libicucore.dylib (but nothing else).
If you need to have icu4c@69.1 first in your PATH, run:
echo 'export PATH="/usr/local/opt/icu4c@69.1/bin:$PATH"' >> ~/.zshrc
echo 'export PATH="/usr/local/opt/icu4c@69.1/sbin:$PATH"' >> ~/.zshrc
For compilers to find icu4c@69.1 you may need to set:
export LDFLAGS="-L/usr/local/opt/icu4c@69.1/lib"
export CPPFLAGS="-I/usr/local/opt/icu4c@69.1/include"
For pkg-config to find icu4c@69.1 you may need to set:
export PKG_CONFIG_PATH="/usr/local/opt/icu4c@69.1/lib/pkgconfig"
For whatever reason, I never was able to get brew link to work. I'd get this error:
$ brew link --force namespace/name/icu4c@69.1
Warning: Refusing to link macOS provided/shadowed software: icu4c@69.1
So instead, I just manually created the symlink.
When the reinstall finishes, you'll see the location of the install, e.g. /usr/local/opt/icu4c@69.1/. So you just need to symlink this over /usr/local/opt/icu4c/, the non versioned folder.
$ ln -nfs /usr/local/opt/icu4c@69.1 /usr/local/opt/icu4c
# If you get an access denied error, you may have to `sudo` the above command
Since the /usr/local/opt/icu4c folder already exists, you'll want to overwrite it, hence the -nf flags.
That's it! You should now have a working node version again.