Run ruff. Also, pip install Python linters. (#762)

Apparently Ubuntu has a "snap" for `ruff`, but it doesn't seem to be
working in 23.10.  So, just `pip install` both ruff and pyflakes if they
are not installed.

It gets a tiny bit complicated with pyflakes, because the Ubuntu package seems to call it `pyflakes3` and the pip package calls it `pyflakes`.  To avoid more complication, I took the risk of setting up an unnecessary virtualenv in one scenario.

.circleci/config.yml

@@ -15,7 +15,8 @@ jobs:
           name: Install
           command: apt install -y lsb-release python3 cmake postgresql libpq-dev
             postgresql-server-dev-all build-essential autoconf dh-autoreconf
-            autoconf-archive automake cppcheck clang
+            autoconf-archive automake cppcheck clang shellcheck
+            python3-virtualenv
       - run:
           name: Identify
           command: lsb_release -a && c++ --version && clang++ --version

.github/workflows/codeql.yml

@@ -42,14 +42,14 @@ jobs:
       - name: Build
         run: |
             gcc --version
-            sudo apt-get install -y postgresql
+            sudo apt-get install -y postgresql virtualenv
             sudo service postgresql start
             sudo su postgres -c "createuser --createdb $(whoami)"
             createdb "$(whoami)"
             # Using clang because currently the gcc build fails with an
             # address sanitizer (asan) link error.
             ./configure --enable-maintainer-mode --enable-audit --disable-documentation --disable-static CXXFLAGS='-O1 -std=c++17' CXX=clang++
-            make -j4 check
+            make -j4 check || (cat test-suite.log && exit 1)
 
       - name: Perform CodeQL Analysis
         uses: github/codeql-action/analyze@v2

tools/lint

@@ -56,7 +56,7 @@ count_includes() {
     # It's OK for the grep to fail.
     find "$SRCDIR/include/pqxx" -type f -print0 |
         ( xargs -0 grep -c "$PAT" || /bin/true ) |
-	sort
+        sort
 }
 
 
@@ -142,10 +142,38 @@ cpplint() {
 
 
 pylint() {
-    if which pyflakes3 >/dev/null
+    local venv
+
+    if ! which pyflakes -o ! which ruff >/dev/null
+    then
+        venv="$(mktemp -d)"
+        virtualenv "$venv"
+        # shellcheck disable=SC1091
+        . "$venv/bin/activate"
+    fi
+    if ! which pyflakes -a ! which pyflakes3 >/dev/null
     then
+        pip install pyflakes
+    fi
+    if ! which ruff >/dev/null
+    then
+        pip install ruff
+    fi
+
+    if which pyflakes
+    then
+        pyflakes "$SRCDIR"/tools/*.py "$SRCDIR"/tools/splitconfig
+    else
         pyflakes3 "$SRCDIR"/tools/*.py "$SRCDIR"/tools/splitconfig
     fi
+
+    ruff "$SRCDIR"/tools/*.py "$SRCDIR"/tools/splitconfig
+
+    if test -n "$venv"
+    then
+        deactivate
+        rm -r "$venv"
+    fi
 }