fixing a Mac home `brew update` that has permission errors (after that I could install plantuml)

I had this occurring on my system:

RetinaMBPro1TB:~ jeroenp$ brew update
error: unable to unlink old 'Library/ENV/pkgconfig/10.11/libcurl.pc' (Permission denied)
error: unable to unlink old 'Library/ENV/pkgconfig/10.11/libxml-2.0.pc' (Permission denied)
error: unable to unlink old 'Library/ENV/pkgconfig/10.11/sqlite3.pc' (Permission denied)
To restore the stashed changes to /usr/local run:
  'cd /usr/local && git stash pop'
Already up-to-date.

This is how I solved it:

RetinaMBPro1TB:~ jeroenp$ ls -al /usr/local | grep -w Library
drwxr-xr-x+ 11 jeroenp  admin   374 Mar  9 19:33 Library
RetinaMBPro1TB:~ jeroenp$ sudo chown -R $USER /usr/local/Library/
Password:
RetinaMBPro1TB:~ jeroenp$ brew update
To restore the stashed changes to /usr/local run:
  'cd /usr/local && git stash pop'
Updated Homebrew from d32996d to 638d755.
==> New Formulae
...
==> Updated Formulae
...
==> Renamed Formulae
...
==> Deleted Formulae
...
RetinaMBPro1TB:~ jeroenp$

The above solution is based on major python problems · Issue #48301 · Homebrew/homebrew

After that, I could install plantuml (which requires java, just so you know) so now I can create SVGs from it locally:

plantuml -tsvg PSO.network-diagram.PlantUML.txt

Note I had to edit the formula so it installs plantuml-8037 or higher (the git version back then installed plantuml-8031) as it fixed a namespace bug. Since plantuml releases often, be prepared to do some version fiddling.

–jeroen