Add running of pylint in 'make check' and fix things

24 files changed, 257 insertions, 209 deletions

diff --git a/Makefile b/Makefile
index a64f92c..edfdc49 100644
--- a/Makefile
+++ b/Makefile
@@ -26,3 +26,4 @@ check:
 	python -m CoverageTestRunner --ignore-missing-from=without-tests
 	rm .coverage
 	pep8 cliapp
+	PYTHONPATH=. pylint --rcfile=pylint.conf cliapp *.py test-plugins/*.py
diff --git a/NEWS b/NEWS
index 7de119c..abda82e 100644
--- a/NEWS
+++ b/NEWS
@@ -12,6 +12,9 @@ Version 1.UNRELEASED
   `cliapp.ssh_runcmd` to allow the caller to easily change to a
   directory on the server.
 
+* Support for `heapy` memory profile has been dropped. It's not
+  packaged for Debian, and is rarely available anywhere.
+
 
 Version 1.20150305
 ------------------
diff --git a/cliapp/__init__.py b/cliapp/__init__.py
index 53cf077..05e8185 100644
--- a/cliapp/__init__.py
+++ b/cliapp/__init__.py
@@ -30,17 +30,17 @@ Homepage: http://liw.fi/cliapp/
 __version__ = '1.20150305'
 
 
-from fmt import TextFormat
-from app import Application, AppException
-from settings import (Settings, log_group_name, config_group_name,
-                      perf_group_name, UnknownConfigVariable)
-from runcmd import runcmd, runcmd_unchecked, shell_quote, ssh_runcmd
+from .fmt import TextFormat
+from .app import Application, AppException
+from .settings import (Settings, log_group_name, config_group_name,
+                       perf_group_name, UnknownConfigVariable)
+from .runcmd import runcmd, runcmd_unchecked, shell_quote, ssh_runcmd
 
 # The plugin system
-from hook import Hook, FilterHook
-from hookmgr import HookManager
-from plugin import Plugin
-from pluginmgr import PluginManager
+from .hook import Hook, FilterHook
+from .hookmgr import HookManager
+from .plugin import Plugin
+from .pluginmgr import PluginManager
 
 
 __all__ = locals()
diff --git a/cliapp/app.py b/cliapp/app.py
index dc6b860..ddc273a 100644
--- a/cliapp/app.py
+++ b/cliapp/app.py
@@ -42,6 +42,7 @@ class AppException(Exception):
     '''
 
     def __init__(self, msg):
+        Exception.__init__(self)
         self.msg = msg
 
     def __str__(self):
@@ -124,16 +125,18 @@ class Application(object):
     def add_settings(self):
         '''Add application specific settings.'''
 
-    def run(self, args=None, stderr=sys.stderr, sysargv=sys.argv,
+    def run(self, args=None, stderr=sys.stderr, sysargv=None,
             log=logging.critical):
         '''Run the application.'''
 
+        sysargv = sys.argv if sysargv is None else sysargv
+
         def run_it():
             self._run(args=args, stderr=stderr, log=log)
 
         if self.settings.progname is None and sysargv:
             self.settings.progname = os.path.basename(sysargv[0])
-        envname = '%s_PROFILE' % self._envname(self.settings.progname)
+        envname = '%s_PROFILE' % self.envname(self.settings.progname)
         profname = os.environ.get(envname, '')
         if profname:  # pragma: no cover
             import cProfile
@@ -141,7 +144,7 @@ class Application(object):
         else:
             run_it()
 
-    def _envname(self, progname):
+    def envname(self, progname):
         '''Create an environment variable name of the name of a program.'''
 
         basename = os.path.basename(progname)
@@ -226,8 +229,9 @@ class Application(object):
             stderr.write(traceback.format_exc())
             sys.exit(1)
 
-        logging.info('%s version %s ends normally' %
-                     (self.settings.progname, self.settings.version))
+        logging.info(
+            '%s version %s ends normally',
+            self.settings.progname, self.settings.version)
 
     def compute_setting_values(self, settings):
         '''Compute setting values after configs and options are parsed.
@@ -302,9 +306,10 @@ class Application(object):
             description = fmt.format(self._format_subcommand_help(cmd))
             text = '%s\n\n%s' % (usage, description)
         else:
-            usage = self._format_usage(all=show_all)
+            usage = self._format_usage(show_all=show_all)
             fmt = cliapp.TextFormat(width=width)
-            description = fmt.format(self._format_description(all=show_all))
+            description = fmt.format(
+                self._format_description(show_all=show_all))
             text = '%s\n\n%s' % (usage, description)
 
         text = self.settings.progname.join(text.split('%prog'))
@@ -330,7 +335,7 @@ class Application(object):
         assert method.startswith('cmd_')
         return method[len('cmd_'):].replace('_', '-')
 
-    def _format_usage(self, all=False):
+    def _format_usage(self, show_all=False):
         '''Format usage, possibly also subcommands, if any.'''
         if self.subcommands:
             lines = []
@@ -349,12 +354,12 @@ class Application(object):
         args = self.cmd_synopsis.get(cmd, '') or ''
         return 'Usage: %%prog [options] %s %s' % (cmd, args)
 
-    def _format_description(self, all=False):
+    def _format_description(self, show_all=False):
         '''Format OptionParser description, with subcommand support.'''
         if self.subcommands:
             summaries = []
             for cmd in sorted(self.subcommands.keys()):
-                if all or cmd not in self.hidden_subcommands:
+                if show_all or cmd not in self.hidden_subcommands:
                     summaries.append(self._format_subcommand_summary(cmd))
             cmd_desc = ''.join(summaries)
             return '%s\n%s' % (self._description or '', cmd_desc)
@@ -458,24 +463,25 @@ class Application(object):
         return '%Y-%m-%d %H:%M:%S'
 
     def log_config(self):
-        logging.info('%s version %s starts' %
-                     (self.settings.progname, self.settings.version))
-        logging.debug('sys.argv: %s' % sys.argv)
+        logging.info(
+            '%s version %s starts',
+            self.settings.progname, self.settings.version)
+        logging.debug('sys.argv: %r', sys.argv)
 
-        logging.debug('current working directory: %s' % os.getcwd())
-        logging.debug('uid: %d' % os.getuid())
-        logging.debug('effective uid: %d' % os.geteuid())
-        logging.debug('gid: %d' % os.getgid())
-        logging.debug('effective gid: %d' % os.getegid())
+        logging.debug('current working directory: %s', os.getcwd())
+        logging.debug('uid: %s', os.getuid())
+        logging.debug('effective uid: %s', os.geteuid())
+        logging.debug('gid: %s', os.getgid())
+        logging.debug('effective gid: %s', os.getegid())
 
         logging.debug('environment variables:')
         for name in os.environ:
-            logging.debug('environment: %s=%s' % (name, os.environ[name]))
+            logging.debug('environment: %s=%s', name, os.environ[name])
         cp = self.settings.as_cp()
         f = StringIO.StringIO()
         cp.write(f)
-        logging.debug('Config:\n%s' % f.getvalue())
-        logging.debug('Python version: %s' % sys.version)
+        logging.debug('Config:\n%s', f.getvalue())
+        logging.debug('Python version: %s', sys.version)
 
     def app_directory(self):
         '''Return the directory where the application class is defined.
@@ -671,30 +677,26 @@ class Application(object):
         # Log wall clock and CPU times for self, children.
         utime, stime, cutime, cstime, elapsed_time = os.times()
         duration = elapsed_time - self._started
-        logging.debug('process duration: %s s' % duration)
-        logging.debug('CPU time, in process: %s s' % utime)
-        logging.debug('CPU time, in system: %s s' % stime)
-        logging.debug('CPU time, in children: %s s' % cutime)
-        logging.debug('CPU time, in system for children: %s s' % cstime)
+        logging.debug('process duration: %s s', duration)
+        logging.debug('CPU time, in process: %s s', utime)
+        logging.debug('CPU time, in system: %s s', stime)
+        logging.debug('CPU time, in children: %s s', cutime)
+        logging.debug('CPU time, in system for children: %s s', cstime)
 
-        logging.debug('dumping memory profiling data: %s' % msg)
-        logging.debug('VmRSS: %s KiB' % self._vmrss())
+        logging.debug('dumping memory profiling data: %s', msg)
+        logging.debug('VmRSS: %s KiB', self._vmrss())
 
         if kind == 'simple':
             return
 
         # These are fairly expensive operations, so we only log them
         # if we're doing expensive stuff anyway.
-        logging.debug('# objects: %d' % len(gc.get_objects()))
-        logging.debug('# garbage: %d' % len(gc.garbage))
-
-        if kind == 'heapy':
-            from guppy import hpy
-            h = hpy()
-            logging.debug('memory profile:\n%s' % h.heap())
-        elif kind == 'meliae':
-            filename = 'obnam-%d.meliae' % self.memory_dump_counter
-            logging.debug('memory profile: see %s' % filename)
+        logging.debug('# objects: %d', len(gc.get_objects()))
+        logging.debug('# garbage: %d', len(gc.garbage))
+
+        if kind == 'meliae':
+            filename = 'obnam-%d.meliae', self.memory_dump_counter
+            logging.debug('memory profile: see %s', filename)
             from meliae import scanner
             scanner.dump_all_objects(filename)
             self.memory_dump_counter += 1
diff --git a/cliapp/app_tests.py b/cliapp/app_tests.py
index a65aee2..fde0916 100644
--- a/cliapp/app_tests.py
+++ b/cliapp/app_tests.py
@@ -15,11 +15,8 @@
 # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 
 
-import optparse
-import os
 import StringIO
 import sys
-import tempfile
 import unittest
 
 import cliapp
@@ -99,7 +96,7 @@ class ApplicationTests(unittest.TestCase):
 
     def test_run_processes_input_files(self):
         self.inputs = []
-        self.app.process_input = lambda name: self.inputs.append(name)
+        self.app.process_input = self.inputs.append
         self.app.run(args=['foo', 'bar'])
         self.assertEqual(self.inputs, ['foo', 'bar'])
 
@@ -126,12 +123,12 @@ class ApplicationTests(unittest.TestCase):
         self.assertEqual(self.called, ['foo', 'bar'])
 
     def test_makes_envname_correctly(self):
-        self.assertEqual(self.app._envname('foo'), 'FOO')
-        self.assertEqual(self.app._envname('foo.py'), 'FOO')
-        self.assertEqual(self.app._envname('foo bar'), 'FOO_BAR')
-        self.assertEqual(self.app._envname('foo-bar'), 'FOO_BAR')
-        self.assertEqual(self.app._envname('foo/bar'), 'BAR')
-        self.assertEqual(self.app._envname('foo_bar'), 'FOO_BAR')
+        self.assertEqual(self.app.envname('foo'), 'FOO')
+        self.assertEqual(self.app.envname('foo.py'), 'FOO')
+        self.assertEqual(self.app.envname('foo bar'), 'FOO_BAR')
+        self.assertEqual(self.app.envname('foo-bar'), 'FOO_BAR')
+        self.assertEqual(self.app.envname('foo/bar'), 'BAR')
+        self.assertEqual(self.app.envname('foo_bar'), 'FOO_BAR')
 
     def test_parses_options(self):
         self.app.settings.string(['foo'], 'foo help')
@@ -142,31 +139,35 @@ class ApplicationTests(unittest.TestCase):
 
     def test_calls_setup(self):
 
+        context = {}
+
         class App(cliapp.Application):
 
             def setup(self):
-                self.setup_called = True
+                context['setup-called'] = True
 
             def process_inputs(self, args):
                 pass
 
         app = App()
         app.run(args=[])
-        self.assertTrue(app.setup_called)
+        self.assertTrue(context['setup-called'])
 
     def test_calls_cleanup(self):
 
+        context = {}
+
         class App(cliapp.Application):
 
             def cleanup(self):
-                self.cleanup_called = True
+                context['cleanup-called'] = True
 
             def process_inputs(self, args):
                 pass
 
         app = App()
         app.run(args=[])
-        self.assertTrue(app.cleanup_called)
+        self.assertTrue(context['cleanup-called'])
 
     def test_process_args_calls_process_inputs(self):
         self.called = False
@@ -201,11 +202,11 @@ class ApplicationTests(unittest.TestCase):
     def test_open_input_opens_file(self):
         f = self.app.open_input('/dev/null')
         self.assert_(isinstance(f, file))
-        self.assertEqual(f.mode, 'r')
+        self.assertEqual(getattr(f, 'mode'), 'r')
 
     def test_open_input_opens_file_in_binary_mode_when_requested(self):
         f = self.app.open_input('/dev/null', mode='rb')
-        self.assertEqual(f.mode, 'rb')
+        self.assertEqual(getattr(f, 'mode'), 'rb')
 
     def test_open_input_opens_stdin_if_dash_given(self):
         self.assertEqual(self.app.open_input('-'), sys.stdin)
@@ -244,7 +245,7 @@ class ApplicationTests(unittest.TestCase):
 
         class Foo(cliapp.Application):
 
-            def open_input(self, name):
+            def open_input(self, name, mode=None):
                 return StringIO.StringIO(''.join('%s%d\n' % (name, i)
                                                  for i in range(2)))
 
@@ -260,7 +261,7 @@ class ApplicationTests(unittest.TestCase):
 
         class Foo(cliapp.Application):
 
-            def open_input(self, name):
+            def open_input(self, name, mode=None):
                 return StringIO.StringIO(''.join('%s%d\n' % (name, i)
                                                  for i in range(2)))
 
@@ -361,6 +362,6 @@ class ExtensibleSubcommandTests(unittest.TestCase):
         self.assertEqual(self.app.subcommands, {})
 
     def test_adds_subcommand(self):
-        help = lambda args: None
-        self.app.add_subcommand('foo', help)
-        self.assertEqual(self.app.subcommands, {'foo': help})
+        help_callback = lambda args: None
+        self.app.add_subcommand('foo', help_callback)
+        self.assertEqual(self.app.subcommands, {'foo': help_callback})
diff --git a/cliapp/hook_tests.py b/cliapp/hook_tests.py
index 3e3de6e..b4779f5 100644
--- a/cliapp/hook_tests.py
+++ b/cliapp/hook_tests.py
@@ -24,6 +24,8 @@ class HookTests(unittest.TestCase):
 
     def setUp(self):
         self.hook = Hook()
+        self.args = None
+        self.kwargs = None
 
     def callback(self, *args, **kwargs):
         self.args = args
@@ -57,6 +59,8 @@ class FilterHookTests(unittest.TestCase):
 
     def setUp(self):
         self.hook = FilterHook()
+        self.args = None
+        self.kwargs = None
 
     def callback(self, data, *args, **kwargs):
         self.args = args
diff --git a/cliapp/plugin.py b/cliapp/plugin.py
index cf964a3..8d9c167 100644
--- a/cliapp/plugin.py
+++ b/cliapp/plugin.py
@@ -26,11 +26,6 @@ other modules as well, such as unit tests, in the same locations.)
 '''
 
 
-import imp
-import inspect
-import os
-
-
 class Plugin(object):
 
     '''Base class for plugins.
@@ -117,7 +112,7 @@ class Plugin(object):
 
     def enable(self):
         '''Enable the plugin.'''
-        raise NotImplemented()
+        raise NotImplementedError()
 
     def disable(self):  # pragma: no cover
         '''Disable the plugin.'''
diff --git a/cliapp/plugin_tests.py b/cliapp/plugin_tests.py
index 951547e..9da69f7 100644
--- a/cliapp/plugin_tests.py
+++ b/cliapp/plugin_tests.py
@@ -20,6 +20,20 @@ import unittest
 from cliapp import Plugin
 
 
+class DummyPlugin(Plugin):
+
+    def __init__(self):
+        Plugin.__init__(self)
+        self.enable_called = False
+        self.disable_called = False
+
+    def enable(self):
+        self.enable_called = True
+
+    def disable(self):
+        self.disable_called = True
+
+
 class PluginTests(unittest.TestCase):
 
     def setUp(self):
@@ -41,11 +55,11 @@ class PluginTests(unittest.TestCase):
         self.assertRaises(Exception, self.plugin.enable)
 
     def test_enable_wrapper_calls_enable(self):
-        self.plugin.enable = lambda: setattr(self, 'enabled', True)
-        self.plugin.enable_wrapper()
-        self.assert_(self.enabled, True)
+        plugin = DummyPlugin()
+        plugin.enable_wrapper()
+        self.assertTrue(plugin.enable_called)
 
     def test_disable_wrapper_calls_disable(self):
-        self.plugin.disable = lambda: setattr(self, 'disabled', True)
-        self.plugin.disable_wrapper()
-        self.assert_(self.disabled, True)
+        plugin = DummyPlugin()
+        plugin.disable_wrapper()
+        self.assertTrue(plugin.disable_called)
diff --git a/cliapp/pluginmgr.py b/cliapp/pluginmgr.py
index 96c726e..ac856b8 100644
--- a/cliapp/pluginmgr.py
+++ b/cliapp/pluginmgr.py
@@ -126,8 +126,8 @@ class PluginManager(object):
     def load_plugin_file(self, pathname):
         '''Return plugin classes in a plugin file.'''
 
-        name, ext = os.path.splitext(os.path.basename(pathname))
-        f = file(pathname, 'r')
+        name, _ = os.path.splitext(os.path.basename(pathname))
+        f = open(pathname, 'r')
         module = imp.load_module(name, f, pathname,
                                  ('.py', 'r', imp.PY_SOURCE))
         f.close()
@@ -161,13 +161,13 @@ class PluginManager(object):
 
         return [int(s) for s in version.split('.')]
 
-    def enable_plugins(self, plugins=None):
+    def enable_plugins(self, plugins=None):  # pragma: no cover
         '''Enable all or selected plugins.'''
 
         for plugin in plugins or self.plugins:
             plugin.enable_wrapper()
 
-    def disable_plugins(self, plugins=None):
+    def disable_plugins(self, plugins=None):  # pragma: no cover
         '''Disable all or selected plugins.'''
 
         for plugin in plugins or self.plugins:
diff --git a/cliapp/pluginmgr_tests.py b/cliapp/pluginmgr_tests.py
index ccca868..e2a79f1 100644
--- a/cliapp/pluginmgr_tests.py
+++ b/cliapp/pluginmgr_tests.py
@@ -80,20 +80,6 @@ class PluginManagerTests(unittest.TestCase):
     def test_raises_keyerror_for_unknown_plugin(self):
         self.assertRaises(KeyError, self.pm.__getitem__, 'Hithere')
 
-    def test_enable_plugins_enables_all_plugins(self):
-        enabled = set()
-        for plugin in self.pm.plugins:
-            plugin.enable = lambda: enabled.add(plugin)
-        self.pm.enable_plugins()
-        self.assertEqual(enabled, set(self.pm.plugins))
-
-    def test_disable_plugins_disables_all_plugins(self):
-        disabled = set()
-        for plugin in self.pm.plugins:
-            plugin.disable = lambda: disabled.add(plugin)
-        self.pm.disable_plugins()
-        self.assertEqual(disabled, set(self.pm.plugins))
-
 
 class PluginManagerCompatibleApplicationVersionTests(unittest.TestCase):
 
diff --git a/cliapp/runcmd.py b/cliapp/runcmd.py
index 6ae2524..b59da70 100644
--- a/cliapp/runcmd.py
+++ b/cliapp/runcmd.py
@@ -51,8 +51,8 @@ def runcmd(argv, *args, **kwargs):
             opts[name] = kwargs[name]
             del kwargs[name]
 
-    exit, out, err = runcmd_unchecked(argv, *args, **kwargs)
-    if exit != 0:
+    exit_code, out, err = runcmd_unchecked(argv, *args, **kwargs)
+    if exit_code != 0:
         msg = 'Command failed: %s\n%s' % (' '.join(argv), err)
         if opts['ignore_fail']:
             if opts['log_error']:
@@ -75,7 +75,7 @@ def runcmd_unchecked(argv, *argvs, **kwargs):
     '''
 
     argvs = [argv] + list(argvs)
-    logging.debug('run external command: %s' % repr(argvs))
+    logging.debug('run external command: %r', argvs)
 
     def pop_kwarg(name, default):
         if name in kwargs:
@@ -206,10 +206,9 @@ def _run_pipeline(procs, feed_stdin, pipe_stdin, pipe_stdout, pipe_stderr,
 
         if rlist or wlist:
             try:
-                r, w, x = select.select(rlist, wlist, [])
-            except select.error, e:  # pragma: no cover
-                err, msg = e.args
-                if err == errno.EINTR:
+                r, w, _ = select.select(rlist, wlist, [])
+            except select.error as e:  # pragma: no cover
+                if e.args[0] == errno.EINTR:
                     break
                 raise
         else:
diff --git a/cliapp/runcmd_tests.py b/cliapp/runcmd_tests.py
index ce7ef8a..878a1b9 100644
--- a/cliapp/runcmd_tests.py
+++ b/cliapp/runcmd_tests.py
@@ -16,11 +16,8 @@
 # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 
 
-import optparse
 import os
-import StringIO
 import subprocess
-import sys
 import tempfile
 import unittest
 
@@ -44,8 +41,8 @@ class RuncmdTests(unittest.TestCase):
                          'hello world\n')
 
     def test_runcmd_returns_stderr_of_command(self):
-        exit, out, err = cliapp.runcmd_unchecked(['ls', 'notexist'])
-        self.assertNotEqual(exit, 0)
+        exit_code, out, err = cliapp.runcmd_unchecked(['ls', 'notexist'])
+        self.assertNotEqual(exit_code, 0)
         self.assertEqual(out, '')
         self.assertNotEqual(err, '')
 
@@ -87,7 +84,7 @@ class RuncmdTests(unittest.TestCase):
             (0, '4\n', ''))
 
     def test_runcmd_redirects_stdin_from_file(self):
-        fd, filename = tempfile.mkstemp()
+        fd, _ = tempfile.mkstemp()
         os.write(fd, 'foobar')
         os.lseek(fd, 0, os.SEEK_SET)
         self.assertEqual(cliapp.runcmd_unchecked(['cat'], stdin=fd),
@@ -96,31 +93,32 @@ class RuncmdTests(unittest.TestCase):
 
     def test_runcmd_redirects_stdout_to_file(self):
         fd, filename = tempfile.mkstemp()
-        exit, out, err = cliapp.runcmd_unchecked(['echo', 'foo'], stdout=fd)
+        exit_code, _, _ = cliapp.runcmd_unchecked(
+            ['echo', 'foo'], stdout=fd)
         os.close(fd)
         with open(filename) as f:
             data = f.read()
-        self.assertEqual(exit, 0)
+        self.assertEqual(exit_code, 0)
         self.assertEqual(data, 'foo\n')
 
     def test_runcmd_redirects_stderr_to_file(self):
         fd, filename = tempfile.mkstemp()
-        exit, out, err = cliapp.runcmd_unchecked(['ls', 'notexist'], stderr=fd)
+        exit_code, _, _ = cliapp.runcmd_unchecked(
+            ['ls', 'notexist'], stderr=fd)
         os.close(fd)
         with open(filename) as f:
             data = f.read()
-        self.assertNotEqual(exit, 0)
+        self.assertNotEqual(exit_code, 0)
         self.assertNotEqual(data, '')
 
     def test_runcmd_unchecked_handles_stdout_err_redirected_to_same_file(self):
         fd, filename = tempfile.mkstemp()
-        exit, out, err = cliapp.runcmd_unchecked(['sleep', '2'],
-                                                 stdout=fd,
-                                                 stderr=subprocess.STDOUT)
+        exit_code, _, _ = cliapp.runcmd_unchecked(
+            ['sleep', '2'], stdout=fd, stderr=subprocess.STDOUT)
         os.close(fd)
         with open(filename) as f:
             data = f.read()
-        self.assertEqual(exit, 0)
+        self.assertEqual(exit_code, 0)
         self.assertEqual(data, '')
 
     def test_runcmd_calls_stdout_callback_when_msg_on_stdout(self):
@@ -134,8 +132,8 @@ class RuncmdTests(unittest.TestCase):
             return 'foo'
 
         test_input = 'hello fox'
-        exit, out, err = cliapp.runcmd_unchecked(['echo', '-n', test_input],
-                                                 stdout_callback=logger)
+        _, out, _ = cliapp.runcmd_unchecked(
+            ['echo', '-n', test_input], stdout_callback=logger)
 
         self.assertEqual(out, 'foo')
         self.assertEqual(msgs, [test_input])
@@ -150,8 +148,8 @@ class RuncmdTests(unittest.TestCase):
             # mangled.
             return None
 
-        exit, out, err = cliapp.runcmd_unchecked(['ls', 'nosuchthing'],
-                                                 stderr_callback=logger)
+        _, _, err = cliapp.runcmd_unchecked(
+            ['ls', 'nosuchthing'], stderr_callback=logger)
 
         # The callback may be called several times, and we have no
         # control over that: output from the subprocess may arrive in
diff --git a/cliapp/settings.py b/cliapp/settings.py
index 80fb461..62586fd 100644
--- a/cliapp/settings.py
+++ b/cliapp/settings.py
@@ -39,8 +39,8 @@ default_group_names = [
 class UnknownConfigVariable(cliapp.AppException):
 
     def __init__(self, filename, name):
-        self.msg = (
-            '%s: Unknown configuration variable %s' % (filename, name))
+        msg = '%s: Unknown configuration variable %s' % (filename, name)
+        cliapp.AppException.__init__(self, msg)
 
     def __str__(self):  # pragma: no cover
         return self.msg
@@ -53,11 +53,11 @@ class Setting(object):
     nargs = 1
     choices = None
 
-    def __init__(self, names, default, help, metavar=None, group=None,
+    def __init__(self, names, default, help_text, metavar=None, group=None,
                  hidden=False):
         self.names = names
         self.set_value(default)
-        self.help = help
+        self.help = help_text
         self.metavar = metavar or self.default_metavar()
         self.group = group
         self.hidden = hidden
@@ -99,10 +99,11 @@ class StringListSetting(Setting):
 
     action = 'append'
 
-    def __init__(self, names, default, help, metavar=None, group=None,
+    def __init__(self, names, default, help_text, metavar=None, group=None,
                  hidden=False):
         Setting.__init__(
-            self, names, [], help, metavar=metavar, group=group, hidden=hidden)
+            self, names, [], help_text, metavar=metavar, group=group,
+            hidden=hidden)
         self.default = default
         self.using_default_value = True
 
@@ -133,10 +134,10 @@ class ChoiceSetting(Setting):
 
     type = 'choice'
 
-    def __init__(self, names, choices, help, metavar=None, group=None,
+    def __init__(self, names, choices, help_text, metavar=None, group=None,
                  hidden=False):
         Setting.__init__(
-            self, names, choices[0], help, metavar=metavar, group=group,
+            self, names, choices[0], help_text, metavar=metavar, group=group,
             hidden=hidden)
         self.choices = choices
 
@@ -312,9 +313,9 @@ class Settings(object):
                     metavar='MODE', default='0600', group=log_group_name)
 
         self.choice(['dump-memory-profile'],
-                    ['simple', 'none', 'meliae', 'heapy'],
+                    ['simple', 'none', 'meliae'],
                     'make memory profiling dumps using METHOD, which is one '
-                    'of: none, simple, meliae, or heapy '
+                    'of: none, simple, or meliae '
                     '(default: %default)',
                     metavar='METHOD',
                     group=perf_group_name)
@@ -331,11 +332,11 @@ class Settings(object):
         for name in setting.names:
             self._settingses[name] = setting
 
-    def string(self, names, help, default='', **kwargs):
+    def string(self, names, help_text, default='', **kwargs):
         '''Add a setting with a string value.'''
-        self._add_setting(StringSetting(names, default, help, **kwargs))
+        self._add_setting(StringSetting(names, default, help_text, **kwargs))
 
-    def string_list(self, names, help, default=None, **kwargs):
+    def string_list(self, names, help_text, default=None, **kwargs):
         '''Add a setting which have multiple string values.
 
         An example would be an option that can be given multiple times
@@ -343,10 +344,10 @@ class Settings(object):
 
         '''
 
-        self._add_setting(StringListSetting(names, default or [], help,
+        self._add_setting(StringListSetting(names, default or [], help_text,
                                             **kwargs))
 
-    def choice(self, names, possibilities, help, **kwargs):
+    def choice(self, names, possibilities, help_text, **kwargs):
         '''Add a setting which chooses from list of acceptable values.
 
         An example would be an option to set debugging level to be
@@ -356,24 +357,25 @@ class Settings(object):
 
         '''
 
-        self._add_setting(ChoiceSetting(names, possibilities, help, **kwargs))
+        self._add_setting(
+            ChoiceSetting(names, possibilities, help_text, **kwargs))
 
-    def boolean(self, names, help, default=False, **kwargs):
+    def boolean(self, names, help_text, default=False, **kwargs):
         '''Add a setting with a boolean value.'''
-        self._add_setting(BooleanSetting(names, default, help, **kwargs))
+        self._add_setting(BooleanSetting(names, default, help_text, **kwargs))
 
-    def bytesize(self, names, help, default=0, **kwargs):
+    def bytesize(self, names, help_text, default=0, **kwargs):
         '''Add a setting with a size in bytes.
 
         The user can use suffixes for kilo/mega/giga/tera/kibi/mibi/gibi/tibi.
 
         '''
 
-        self._add_setting(ByteSizeSetting(names, default, help, **kwargs))
+        self._add_setting(ByteSizeSetting(names, default, help_text, **kwargs))
 
-    def integer(self, names, help, default=0, **kwargs):
+    def integer(self, names, help_text, default=0, **kwargs):
         '''Add an integer setting.'''
-        self._add_setting(IntegerSetting(names, default, help, **kwargs))
+        self._add_setting(IntegerSetting(names, default, help_text, **kwargs))
 
     def __getitem__(self, name):
         return self._settingses[name].value
@@ -424,7 +426,7 @@ class Settings(object):
         return name
 
     def build_parser(self, configs_only=False, arg_synopsis=None,
-                     cmd_synopsis=None, deferred_last=[], all_options=False):
+                     cmd_synopsis=None, deferred_last=None, all_options=False):
         '''Build OptionParser for parsing command line.'''
 
         # Call a callback function unless we're in configs_only mode.
@@ -660,7 +662,7 @@ class Settings(object):
         if suppress_errors:
             p.error = lambda msg: sys.exit(1)
 
-        options, args = p.parse_args(args)
+        _, args = p.parse_args(args)
         if compute_setting_values:  # pragma: no cover
             compute_setting_values(self)
         for callback in deferred_last:  # pragma: no cover
@@ -668,7 +670,7 @@ class Settings(object):
         return args
 
     @property
-    def _default_config_files(self):
+    def default_config_files(self):
         '''Return list of default config files to read.
 
         The names of the files are dependent on the name of the program,
@@ -681,14 +683,14 @@ class Settings(object):
         configs = []
 
         configs.append('/etc/%s.conf' % self.progname)
-        configs += self._listconfs('/etc/%s' % self.progname)
+        configs += self.listconfs('/etc/%s' % self.progname)
         configs.append(os.path.expanduser('~/.%s.conf' % self.progname))
-        configs += self._listconfs(
+        configs += self.listconfs(
             os.path.expanduser('~/.config/%s' % self.progname))
 
         return configs
 
-    def _listconfs(self, dirname, listdir=os.listdir):
+    def listconfs(self, dirname, listdir=os.listdir):
         '''Return list of pathnames to config files in dirname.
 
         Config files are expectd to have names ending in '.conf'.
@@ -709,7 +711,7 @@ class Settings(object):
 
     def _get_config_files(self):
         if self._config_files is None:
-            self._config_files = self._default_config_files
+            self._config_files = self.default_config_files
         return self._config_files
 
     def _set_config_files(self, config_files):
@@ -725,7 +727,7 @@ class Settings(object):
         s.parse_value(raw_string)
         return s
 
-    def load_configs(self, open=open):
+    def load_configs(self, open_file=open):
         '''Load all config files in self.config_files.
 
         Silently ignore files that do not exist.
@@ -737,7 +739,7 @@ class Settings(object):
 
         for pathname in self.config_files:
             try:
-                f = open(pathname)
+                f = open_file(pathname)
             except IOError:
                 pass
             else:
@@ -753,7 +755,7 @@ class Settings(object):
         # Remember the ConfigParser for use in as_cp later on.
         self._cp = cp
 
-    def _generate_manpage(self, o, os, value, p):  # pragma: no cover
+    def _generate_manpage(self, o, dummy, value, p):  # pragma: no cover
         template = open(value).read()
         generator = ManpageGenerator(template, p, self._arg_synopsis,
                                      self._cmd_synopsis)
diff --git a/cliapp/settings_tests.py b/cliapp/settings_tests.py
index b5b9eaa..1d6fa84 100644
--- a/cliapp/settings_tests.py
+++ b/cliapp/settings_tests.py
@@ -15,9 +15,7 @@
 # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 
 
-import optparse
 import StringIO
-import sys
 import unittest
 
 import cliapp
@@ -171,14 +169,14 @@ class SettingsTests(unittest.TestCase):
         def fake_open(filename):
             return StringIO.StringIO('[config]\nfoo = yes\n')
         self.settings.boolean(['foo'], 'foo help')
-        self.settings.load_configs(open=fake_open)
+        self.settings.load_configs(open_file=fake_open)
         self.assertEqual(self.settings['foo'], True)
 
     def test_sets_boolean_to_false_from_config_file(self):
         def fake_open(filename):
             return StringIO.StringIO('[config]\nfoo = False\n')
         self.settings.boolean(['foo'], 'foo help')
-        self.settings.load_configs(open=fake_open)
+        self.settings.load_configs(open_file=fake_open)
         self.assertEqual(self.settings['foo'], False)
 
     def test_adds_bytesize_setting(self):
@@ -232,33 +230,33 @@ class SettingsTests(unittest.TestCase):
         self.assertEqual(self.settings['foo'], 123)
 
     def test_has_list_of_default_config_files(self):
-        defaults = self.settings._default_config_files
+        defaults = self.settings.default_config_files
         self.assert_(isinstance(defaults, list))
         self.assert_(len(defaults) > 0)
 
     def test_listconfs_returns_empty_list_for_nonexistent_directory(self):
-        self.assertEqual(self.settings._listconfs('notexist'), [])
+        self.assertEqual(self.settings.listconfs('notexist'), [])
 
     def test_listconfs_lists_config_files_only(self):
         def mock_listdir(dirname):
             return ['foo.conf', 'foo.notconf']
-        names = self.settings._listconfs('.', listdir=mock_listdir)
+        names = self.settings.listconfs('.', listdir=mock_listdir)
         self.assertEqual(names, ['./foo.conf'])
 
     def test_listconfs_sorts_names_in_C_locale(self):
         def mock_listdir(dirname):
             return ['foo.conf', 'bar.conf']
-        names = self.settings._listconfs('.', listdir=mock_listdir)
+        names = self.settings.listconfs('.', listdir=mock_listdir)
         self.assertEqual(names, ['./bar.conf', './foo.conf'])
 
     def test_has_config_files_attribute(self):
         self.assertEqual(self.settings.config_files,
-                         self.settings._default_config_files)
+                         self.settings.default_config_files)
 
     def test_has_config_files_list_can_be_changed(self):
         self.settings.config_files += ['./foo']
         self.assertEqual(self.settings.config_files,
-                         self.settings._default_config_files + ['./foo'])
+                         self.settings.default_config_files + ['./foo'])
 
     def test_loads_config_files(self):
 
@@ -270,7 +268,7 @@ foo = yeehaa
 
         self.settings.string(['foo'], 'foo help')
         self.settings.config_files = ['whatever.conf']
-        self.settings.load_configs(open=mock_open)
+        self.settings.load_configs(open_file=mock_open)
         self.assertEqual(self.settings['foo'], 'yeehaa')
 
     def test_loads_string_list_from_config_files(self):
@@ -285,7 +283,7 @@ bar = ping, pong
         self.settings.string_list(['foo'], 'foo help')
         self.settings.string_list(['bar'], 'bar help')
         self.settings.config_files = ['whatever.conf']
-        self.settings.load_configs(open=mock_open)
+        self.settings.load_configs(open_file=mock_open)
         self.assertEqual(self.settings['foo'], ['yeehaa'])
         self.assertEqual(self.settings['bar'], ['ping', 'pong'])
 
@@ -299,7 +297,7 @@ bar = ping, pong
         self.settings.string(['foo'], 'foo help', default='foo')
         self.settings.string_list(['bar'], 'bar help', default=['bar'])
         self.settings.config_files = ['whatever.conf']
-        self.settings.load_configs(open=mock_open)
+        self.settings.load_configs(open_file=mock_open)
         self.assertEqual(self.settings['foo'], 'foo')
         self.assertEqual(self.settings['bar'], ['bar'])
 
@@ -315,7 +313,7 @@ bar = ping, pong
         self.settings.string(['foo'], 'foo help', default='foo')
         self.settings.string_list(['bar'], 'bar help', default=['bar'])
         self.settings.config_files = ['whatever.conf']
-        self.settings.load_configs(open=mock_open)
+        self.settings.load_configs(open_file=mock_open)
         self.assertEqual(self.settings['foo'], 'yeehaa')
         self.assertEqual(self.settings['bar'], ['ping', 'pong'])
 
@@ -331,7 +329,7 @@ bar = ping, pong
         self.settings.string(['foo'], 'foo help', default='foo')
         self.settings.string_list(['bar'], 'bar help', default=['bar'])
         self.settings.config_files = ['whatever.conf']
-        self.settings.load_configs(open=mock_open)
+        self.settings.load_configs(open_file=mock_open)
         self.settings.parse_args(['--foo=red', '--bar=blue', '--bar=white'])
         self.assertEqual(self.settings['foo'], 'red')
         self.assertEqual(self.settings['bar'], ['blue', 'white'])
@@ -347,19 +345,19 @@ unknown = variable
         self.assertRaises(
             cliapp.UnknownConfigVariable,
             self.settings.load_configs,
-            open=mock_open)
+            open_file=mock_open)
 
     def test_load_configs_ignore_errors_opening_a_file(self):
 
         def mock_open(filename, mode=None):
             raise IOError()
 
-        self.assertEqual(self.settings.load_configs(open=mock_open), None)
+        self.assertEqual(self.settings.load_configs(open_file=mock_open), None)
 
     def test_adds_config_file_with_dash_dash_config(self):
         self.settings.parse_args(['--config=foo.conf'])
         self.assertEqual(self.settings.config_files,
-                         self.settings._default_config_files + ['foo.conf'])
+                         self.settings.default_config_files + ['foo.conf'])
 
     def test_ignores_default_configs(self):
         self.settings.parse_args(['--no-default-configs'])
@@ -444,7 +442,7 @@ bar = dodo
 
         self.settings.string(['foo'], 'foo help', default='foo')
         self.settings.config_files = ['whatever.conf']
-        self.settings.load_configs(open=mock_open)
+        self.settings.load_configs(open_file=mock_open)
         cp = self.settings.as_cp()
 
         self.assertEqual(sorted(cp.sections()), ['config', 'other'])
diff --git a/example.py b/example.py
index 14a56db..fe282be 100644
--- a/example.py
+++ b/example.py
@@ -31,16 +31,25 @@ class ExampleApp(cliapp.Application):
     '''A little fgrep-like tool.'''
 
     def add_settings(self):
-        self.settings.string_list(['pattern', 'e'],
-                                  'search for regular expression PATTERN',
-                                   metavar='REGEXP')
-
-        self.settings.boolean(['dummy'], 'this setting is ignored',
-                              group='Test Group')
-
-        self.settings.string(['yoyo'], 'yoyo', group=cliapp.config_group_name)
-
-        self.settings.string(['nono'], 'nono', default=None)
+        self.settings.string_list(
+            ['pattern', 'e'],
+            'search for regular expression PATTERN',
+            metavar='REGEXP')
+
+        self.settings.boolean(
+            ['dummy'],
+            'this setting is ignored',
+            group='Test Group')
+
+        self.settings.string(
+            ['yoyo'],
+            'yoyo',
+            group=cliapp.config_group_name)
+
+        self.settings.string(
+            ['nono'],
+            'nono',
+            default=None)
 
     # We override process_inputs to be able to do something after the last
     # input line.
@@ -50,12 +59,12 @@ class ExampleApp(cliapp.Application):
         self.output.write('There were %s matches.\n' % self.matches)
 
     def process_input_line(self, name, line):
-        logging.debug('processing %s:%s' % (name, self.lineno))
+        logging.debug('processing %s:%s', name, self.lineno)
         for pattern in self.settings['pattern']:
             if pattern in line:
                 self.output.write('%s:%s: %s' % (name, self.lineno, line))
                 self.matches += 1
-                logging.debug('Match: %s line %d' % (name, self.lineno))
+                logging.debug('Match: %s line %d', name, self.lineno)
 
 
 app = ExampleApp(version='0.1.2')
diff --git a/example2.py b/example2.py
index 1f061b9..972e880 100644
--- a/example2.py
+++ b/example2.py
@@ -23,7 +23,6 @@ Greet or insult people.
 
 
 import cliapp
-import logging
 
 
 class ExampleApp(cliapp.Application):
@@ -54,14 +53,17 @@ class ExampleApp(cliapp.Application):
             self.output.write('you suck, %s\n' % arg)
 
 
-app = ExampleApp(version='0.1.2', description='''
+app = ExampleApp(
+    version='0.1.2',
+    description='''
 Greet the user.
 Or possibly insult them. User's choice.
 ''',
-epilog='''
+    epilog='''
 This is the epilog.
 
 I hope you like it.
 ''')
+
 app.run()
 
diff --git a/example4.py b/example4.py
index f500bbd..c6ba78f 100644
--- a/example4.py
+++ b/example4.py
@@ -16,7 +16,6 @@
 
 
 import cliapp
-import logging
 
 
 class ExampleApp(cliapp.Application):
diff --git a/example5.py b/example5.py
index 2e83bae..c6ab7b2 100644
--- a/example5.py
+++ b/example5.py
@@ -16,7 +16,6 @@
 
 
 import cliapp
-import logging
 
 
 class LoggerApp(cliapp.Application):
diff --git a/pylint.conf b/pylint.conf
new file mode 100644
index 0000000..b36b2aa
--- /dev/null
+++ b/pylint.conf
@@ -0,0 +1,28 @@
+[MASTER]
+persistent=no
+
+[MESSAGES CONTROL]
+disable=
+    attribute-defined-outside-init,
+    bad-builtin,
+    blacklisted-name,
+    cyclic-import,
+    invalid-name,
+    missing-docstring,
+    no-self-use,
+    protected-access,
+    star-args,
+    too-few-public-methods,
+    too-many-arguments,
+    too-many-branches,
+    too-many-instance-attributes,
+    too-many-locals,
+    too-many-public-methods,
+    too-many-statements,
+    unused-argument
+
+[REPORTS]
+reports=no
+
+[SIMILARITIES]
+min-similarity-lines=999
diff --git a/setup.py b/setup.py
index 2ed1543..6a7024d 100644
--- a/setup.py
+++ b/setup.py
@@ -21,19 +21,20 @@ import glob
 import cliapp
 
 
-setup(name='cliapp',
-      version=cliapp.__version__,
-      author='Lars Wirzenius',
-      author_email='liw@liw.fi',
-      url='http://liw.fi/cliapp/',
-      description='framework for Unix command line programs',
-      long_description='''\
-cliapp makes it easier to write typical Unix command line programs,
-by taking care of the common tasks they need to do, such as
-parsing the command line, reading configuration files, setting
-up logging, iterating over lines of input files, and so on.
-''',
-      classifiers=[
+setup(
+    name='cliapp',
+    version=cliapp.__version__,
+    author='Lars Wirzenius',
+    author_email='liw@liw.fi',
+    url='http://liw.fi/cliapp/',
+    description='framework for Unix command line programs',
+    long_description='''\
+    cliapp makes it easier to write typical Unix command line programs,
+    by taking care of the common tasks they need to do, such as
+    parsing the command line, reading configuration files, setting
+    up logging, iterating over lines of input files, and so on.
+    ''',
+    classifiers=[
         'Development Status :: 4 - Beta',
         'Environment :: Console',
         'Intended Audience :: Developers',
@@ -44,7 +45,7 @@ up logging, iterating over lines of input files, and so on.
         'Topic :: Software Development :: User Interfaces',
         'Topic :: Text Processing :: Filters',
         'Topic :: Utilities',
-      ],
-      packages=['cliapp'],
-      data_files=[('share/man/man5', glob.glob('*.5'))],
-     )
+    ],
+    packages=['cliapp'],
+    data_files=[('share/man/man5', glob.glob('*.5'))],
+)
diff --git a/test-plugins/aaa_hello_plugin.py b/test-plugins/aaa_hello_plugin.py
index b8f3253..9af3f83 100644
--- a/test-plugins/aaa_hello_plugin.py
+++ b/test-plugins/aaa_hello_plugin.py
@@ -6,3 +6,5 @@ class Hello(cliapp.Plugin):
         self.foo = foo
         self.bar = bar
 
+    def enable(self):
+        pass
diff --git a/test-plugins/hello_plugin.py b/test-plugins/hello_plugin.py
index a102502..c47adb7 100644
--- a/test-plugins/hello_plugin.py
+++ b/test-plugins/hello_plugin.py
@@ -13,3 +13,5 @@ class Hello(cliapp.Plugin):
     def setup(self):
         self.setup_called = True
 
+    def enable(self):
+        pass
diff --git a/test-plugins/oldhello_plugin.py b/test-plugins/oldhello_plugin.py
index e401ff7..9af3f83 100644
--- a/test-plugins/oldhello_plugin.py
+++ b/test-plugins/oldhello_plugin.py
@@ -6,4 +6,5 @@ class Hello(cliapp.Plugin):
         self.foo = foo
         self.bar = bar
 
-
+    def enable(self):
+        pass
diff --git a/test-plugins/wrongversion_plugin.py b/test-plugins/wrongversion_plugin.py
index 9f54908..caf6307 100644
--- a/test-plugins/wrongversion_plugin.py
+++ b/test-plugins/wrongversion_plugin.py
@@ -10,3 +10,5 @@ class WrongVersion(cliapp.Plugin):
     def __init__(self, *args, **kwargs):
         pass
 
+    def enable(self):
+        pass