cleanup: run pyflakes as a part of scripts/run-all-cleanup

pyflakes has no usable configuration options, so create a small wrapper script.
Instead of having two wrapper scripts (with one being almost nothing and the
other containing configuration), just keep it simple and use one combined.

scripts/pyflakes

@@ -0,0 +1,37 b''
+#!/usr/bin/env python3
+"""
+pyflakes with filter configuration for Kallithea.
+Inspired by pyflakes/api.py and flake8/plugins/pyflakes.py .
+"""
+
+import sys
+import pyflakes.api
+import pyflakes.messages
+
+class Reporter:
+
+    warned = False
+
+    def flake(self, warning):
+        # ignore known warnings
+        if isinstance(warning, pyflakes.messages.UnusedVariable):
+            return
+        if warning.filename == 'kallithea/bin/kallithea_cli_ishell.py':
+            if isinstance(warning, pyflakes.messages.ImportStarUsed) and warning.message_args == ('kallithea.model.db',):
+                return
+            if isinstance(warning, pyflakes.messages.UnusedImport) and warning.message_args == ('kallithea.model.db.*',):
+                return
+
+        print('%s:%s %s   [%s %s]' % (warning.filename, warning.lineno, warning.message % warning.message_args, type(warning).__name__, warning.message_args))
+        self.warned = True
+
+    def unexpectedError(self, filename, msg):
+        print('Unexpected error for %s: %s' % (filename, msg))
+
+
+reporter = Reporter()
+
+for filename in sorted(set(sys.argv[1:])):
+    pyflakes.api.checkPath(filename, reporter=reporter)
+if reporter.warned:
+    raise SystemExit(1)

dev_requirements.txt

@@ -1,8 +1,9 b''
 pytest >= 4.6.6, < 5.4
 pytest-sugar >= 0.9.2, < 0.10
 pytest-benchmark >= 3.2.2, < 3.3
 pytest-localserver >= 0.5.0, < 0.6
 mock >= 3.0.0, < 4.1
 Sphinx >= 1.8.0, < 2.4
 WebTest >= 2.0.6, < 2.1
 isort == 4.3.21
+pyflakes == 2.1.1

scripts/run-all-cleanup

@@ -1,10 +1,12 b''
 #!/bin/sh
 
 # Convenience script for running various idempotent source code cleanup scripts
 
 set -e
 set -x
 
 scripts/docs-headings.py
 scripts/generate-ini.py
 scripts/whitespacecleanup.sh
+
+hg loc 'set:!binary()&grep("^#!.*python")' '*.py' | xargs scripts/pyflakes