Fix broken MacOS and Ubuntu18.04 runs. (#4517)

* Support Ubuntu 18.04 black.

* Fix broken CI runs.

* Always pass the brew command.

* Use aggressive method for MacOS-13 only.

.github/workflows/ci-test-mac.yml

@@ -93,6 +93,26 @@ jobs:
 
     - name: Install dependencies (MacOS)
       run: |
+          # FIXME: We should not need to do this, but there are currently some complications with Github CI.
+          # See https://github.com/actions/runner-images/issues/4020.
+          # See https://github.com/actions/runner-images/issues/8838.
+          brew unlink [email protected]
+          brew uninstall --force azure-cli
+          brew uninstall --force aws-sam-cli
+          brew uninstall --force pipx
+          brew uninstall --force [email protected]
+          brew uninstall --force [email protected]
+          rm -f '/usr/local/bin/2to3'
+          rm -f '/usr/local/bin/2to3-3.12'
+          rm -f '/usr/local/bin/idle3'
+          rm -f '/usr/local/bin/idle3.12'
+          rm -f '/usr/local/bin/pydoc3'
+          rm -f '/usr/local/bin/pydoc3.12'
+          rm -f '/usr/local/bin/python3'
+          rm -f '/usr/local/bin/python3-config'
+          rm -f '/usr/local/bin/python3.12'
+          rm -f '/usr/local/bin/python3.12-config'
+          brew install python@3 || brew link --overwrite python@3
            tools/install_mac_deps.sh
 
     - name: Build (MacOS)

requirements.txt

@@ -5,12 +5,14 @@ ply==3.11
 ptf==0.9.4
 scapy==2.5.0
 clang-format==18.1.0
-black==24.2.0
-isort==5.13.2
+isort==5.13.2; python_version > '3.6'
+black==24.2.0; python_version > '3.6'
 protobuf==3.20.2; python_version > '3.6'
 grpcio==1.59.3; python_version > '3.6'
 googleapis-common-protos==1.53.0; python_version > '3.6'
-# Ubuntu 18.04 uses Python 3.6, which is not supported by recent versions of Protobuf.
+# Ubuntu 18.04 uses Python 3.6, which is not supported by recent versions of Protobuf and Black.
 protobuf==3.19.2; python_version <= '3.6'
 googleapis-common-protos==1.53.0; python_version <= '3.6'
 grpcio==1.48.2; python_version <= '3.6'
+isort==5.10.1; python_version <= '3.6'
+black==22.8.0; python_version <= '3.6'

tools/install_mac_deps.sh

@@ -62,4 +62,5 @@ fi
 source ~/.bash_profile
 
 # Install required pip packages
-pip3 install --user -r requirements.txt
+# TODO: Should we use --break-system-packages or should we set up a venv?
+pip3 install --user --break-system-packages -r requirements.txt