Use older Tor on macOS + Python 2.7

.github/workflows/ci.yml

@@ -189,10 +189,21 @@ jobs:
         if: matrix.os == 'ubuntu-latest'
         run: sudo apt install tor
 
-      - name: Install Tor [macOS]
-        if: matrix.os == 'macos-latest'
+      - name: Install Tor [macOS, ${{ matrix.python-version }} ]
+        if: ${{ ( matrix.os == 'macos-latest' ) &&  ( matrix.python-version != '2.7' ) }}
         run: brew install tor
         
+      # TODO: See https://tahoe-lafs.org/trac/tahoe-lafs/ticket/3744.
+      # We have to use an older version of Tor for running integration
+      # tests on macOS using Python 2.7.  We should stop doing this
+      # when Python 2.7 is dropped.
+      - name: Install Tor [macOS, ${{ matrix.python-version }} ]
+        if: ${{ ( matrix.os == 'macos-latest' ) &&  ( matrix.python-version == '2.7' ) }}
+        run: |
+          brew extract --version 0.4.5.8 tor homebrew/cask
+          brew install tor@0.4.5.8
+          brew link --overwrite tor@0.4.5.8
+
       - name: Install Tor [Windows]
         if: matrix.os == 'windows-latest'
         uses: crazy-max/ghaction-chocolatey@v1