Fix CI on macOS 13.

.github/workflows/macos.yml

@@ -22,7 +22,7 @@ jobs:
         with:
           ref: ${{ github.event.pull_request.head.sha }}
       - name: Set up Python
-        uses: actions/setup-python@v4.4.0
+        uses: actions/setup-python@v5
         with:
           python-version: ${{ env.python_version }}
       - name: Install macOS Dependencies

.github/workflows/run-tests.yml

@@ -36,26 +36,34 @@ jobs:
       run: |
         sudo apt-get update
         sudo apt-get -y install -qq gettext gir1.2-gdkpixbuf-2.0 gir1.2-glib-2.0 gir1.2-gtk-3.0 gir1.2-gtksource-4 gir1.2-pango-1.0 gir1.2-webkit2-4.0 python3 python3-enchant python3-gi python3-yaml
+        python3 -m pip install setuptools tox
 
     - name: Install dependencies (macOS)
       if: startsWith(matrix.os, 'macos')
       run: |
         # We need pygobject from PyPI. Using only pygobject3 from homebrew leads to "gi module not found".
-        brew install gettext gtk+3 gobject-introspection glib libffi cairo gtksourceview3 atk librsvg gsettings-desktop-schemas adwaita-icon-theme enchant
-        python3 -m pip install pyenchant pygobject pyyaml
+        # Homebrew complains about [email protected] files that are overwritten, so we remove them.
+        # Some can be removed by unlinking [email protected], others need to be removed manually.
+        brew unlink [email protected]
+        brew link --overwrite [email protected]
+        sudo rm -r /usr/local/bin/2to3 /usr/local/bin/idle3 /usr/local/bin/pydoc3 /usr/local/bin/python3 /usr/local/bin/python3-config /usr/local/share/man/man1/python3.1 /usr/local/lib/pkgconfig/python3-embed.pc /usr/local/lib/pkgconfig/python3.pc /usr/local/Frameworks/Python.framework/Headers /usr/local/Frameworks/Python.framework/Python /usr/local/Frameworks/Python.framework/Resources /usr/local/Frameworks/Python.framework/Versions/Current
+        brew install gettext gobject-introspection gtk+3 libffi cairo gtksourceview3 librsvg adwaita-icon-theme enchant
+        # Removing the Python files above makes pip complain about "managed environments", so we need to "break system packages".
+        python3 -m pip install --break-system-packages pyenchant pygobject pyyaml
+        python3 -m pip install --break-system-packages setuptools tox
       env:
+        # https://docs.brew.sh/Manpage#install-options-formulacask-
         HOMEBREW_NO_INSTALLED_DEPENDENTS_CHECK: on
-
-    - name: Install common dependencies
-      run: |
-        python3 -m pip install setuptools tox
+        HOMEBREW_NO_INSTALL_CLEANUP: on
+        HOMEBREW_NO_INSTALL_UPGRADE: on
 
     - name: Check style
       if: matrix.os == 'ubuntu-22.04'
       run: |
         python3 -m tox -v -e style
 
     - name: Run tests
+      if: matrix.os == 'ubuntu-22.04'  # pip on macOS needs --break-system-packages
       run: |
         python3 -c "import gi"
         python3 -m tox -v -e py