Disable pylint rules in specific versions only

Instead of putting rule disable comments in the code, where they have to
be understood by all versions of pylint, instead use command-line
arguments to disable rules for specific versions. This avoids the
situation where a rule is unknown in earlier versions of pylint, so the
disable comment generates and error.

.github/workflows/ci.yml

@@ -9,6 +9,15 @@ jobs:
     strategy:
       matrix:
         python-version: [ 2.7, 3.5, 3.6, 3.7, 3.8, 3.9 ]
+        include:
+          - python-version: 3.6
+            disable: '--disable=consider-using-f-string'
+          - python-version: 3.7
+            disable: '--disable=consider-using-f-string'
+          - python-version: 3.8
+            disable: '--disable=consider-using-f-string,redundant-u-string-prefix'
+          - python-version: 3.9
+            disable: '--disable=consider-using-f-string,redundant-u-string-prefix'
     steps:
       - uses: actions/checkout@v2
       - name: Set up Python ${{ matrix.python-version }}
@@ -20,7 +29,7 @@ jobs:
           python -m pip install --upgrade pip
           pip install pylint flake8 pytest
       - name: Lint with pylint
-        run: pylint *.py
+        run: pylint ${{ matrix.disable }} *.py
       - name: Lint with flake8
         run: flake8 *.py
       - name: Test with pytest

download_trailers.py

@@ -27,10 +27,6 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-# We still support Python 2, so we can't use f-strings, even though pylint
-# in recent versions of Python 3 wants us to.
-# pylint: disable=consider-using-f-string
-
 import argparse
 import io
 import json