Switch to flake8 as a better way of running pyflakes.

Makefile

@@ -6,7 +6,7 @@ default:
 
 PYTHON=python
 export PYTHON
-PYFLAKES=pyflakes
+PYFLAKES=flake8
 export PYFLAKES
 
 SOURCES=src/allmydata static misc setup.py

setup.cfg

@@ -5,3 +5,8 @@ install = update_version install
 develop = update_version develop
 bdist_egg = update_version bdist_egg
 bdist_wheel = update_version bdist_wheel
+
+[flake8]
+# For now, only use pyflakes errors; flake8 is still helpful because it allows
+# ignoring specific errors/warnings when needed.
+select = F

setup.py

@@ -353,11 +353,12 @@ setup(name="tahoe-lafs", # also set in __init__.py
           # discussion.
           ':sys_platform=="win32"': ["pywin32 != 226"],
           "test": [
+              "flake8",
               # Pin a specific pyflakes so we don't have different folks
               # disagreeing on what is or is not a lint issue.  We can bump
               # this version from time to time, but we will do it
               # intentionally.
-              "pyflakes == 2.1.0",
+              "pyflakes == 2.2.0",
               # coverage 5.0 breaks the integration tests in some opaque way.
               # This probably needs to be addressed in a more permanent way
               # eventually...

tox.ini

@@ -75,7 +75,7 @@ commands =
 whitelist_externals =
          /bin/mv
 commands =
-         pyflakes src static misc setup.py
+         flake8 src static misc setup.py
          python misc/coding_tools/check-umids.py src
          python misc/coding_tools/check-debugging.py
          python misc/coding_tools/find-trailing-spaces.py -r src static misc setup.py