Run linters during CI

.cirrus.yml

@@ -12,6 +12,22 @@ docs_task:
     - make -C docs/ html
 
 
+lint_task:
+  skip: $CIRRUS_BRANCH =~ '.*\.tmp'
+  container:
+    image: python:3.7-slim
+
+  install_script:
+    - pip install --upgrade-strategy eager -U -r requirements-tests.txt
+    - pip install --upgrade-strategy eager -U -r requirements-lint.txt
+    - pip install -e .
+
+  script:
+    - python3 --version
+    - pip list
+    - ./lint.sh
+
+
 task:
   name: "Linux $IMAGE"
   skip: $CIRRUS_BRANCH =~ '.*\.tmp'

.common.sh

@@ -0,0 +1,14 @@
+set -euo pipefail
+
+function run() {
+    echo '$' "$@"
+    "$@"
+    echo
+}
+
+PY=${PY-python3}
+
+if ! command -v $PY >/dev/null; then
+    echo "Python interpreter '$PY' not found" >&2
+    exit 1
+fi

docs/conf.py

@@ -142,7 +142,7 @@
 # (source start file, name, description, authors, manual section).
 man_pages = [
     (master_doc, 'pursuedpybear', 'PursuedPyBear Documentation',
-     [author], 1)
+     [author], 1),
 ]
 
 
@@ -181,4 +181,4 @@
 # -- Options for todo extension ----------------------------------------------
 
 # If true, `todo` and `todoList` produce output, else they produce nothing.
-todo_include_todos = True
+todo_include_todos = True

examples/animated_sprite.py

@@ -1,8 +1,8 @@
 import math
 
 import ppb
-from ppb.features.animation import Animation
 import ppb.events as events
+from ppb.features.animation import Animation
 
 
 class Blob(ppb.BaseSprite):

examples/framecount.py

@@ -8,6 +8,7 @@
 
 import logging
 import time
+
 import ppb
 
 

examples/targets.py

@@ -1,7 +1,7 @@
 import logging
+
 import ppb
-from ppb import Vector
-from ppb import keycodes
+from ppb import keycodes, Vector
 
 
 class MoverMixin(ppb.BaseSprite):
@@ -39,7 +39,7 @@ def on_button_pressed(self, event, signal):
     def _fire_bullet(self, scene):
         scene.add(
             Bullet(pos=self.position),
-            tags=['bullet']
+            tags=['bullet'],
         )
 
 
@@ -51,7 +51,7 @@ def on_update(self, update, signal):
         super().on_update(update, signal)  # Execute movement
 
         scene = update.scene
-        
+
         if self.position.y > scene.main_camera.frame_bottom:
             scene.remove(self)
         else:

examples/targets_with_twisted.py

@@ -1,15 +1,13 @@
-import logging
-import ppb
-from ppb import Vector
-from ppb import keycodes
-from twisted.internet import defer
-from twisted.internet import task
-from twisted.internet import endpoints
-from twisted.web.server import Site
-import klein
 from dataclasses import dataclass
 from typing import Any
 
+import klein
+from twisted.internet import defer, endpoints, task
+from twisted.web.server import Site
+
+import ppb
+from ppb import keycodes, Vector
+
 
 class MoverMixin(ppb.BaseSprite):
     velocity = Vector(0, 0)
@@ -45,7 +43,7 @@ def on_button_pressed(self, event, signal):
     def _fire_bullet(self, scene):
         scene.add(
             Bullet(pos=self.position),
-            tags=['bullet']
+            tags=['bullet'],
         )
 
 
@@ -74,7 +72,7 @@ def on_update(self, update, signal):
         super().on_update(update, signal)  # Execute movement
 
         scene = update.scene
-        
+
         if self.position.y > scene.main_camera.frame_bottom:
             scene.remove(self)
         else:
@@ -102,7 +100,7 @@ def __init__(self, *p, **kw):
             self.add(Target(pos=Vector(x, 1.875)), tags=['target'])
 
 
-######### This is "non-game-specific code" ###########
+# This is "non-game-specific code"
 class _FinishLoop(Exception):
     pass
 
@@ -119,7 +117,7 @@ def loop_once(engine):
         yield loop.start(0.001)
     except _FinishLoop:
         pass
-######### End of "non-game-specific code" ###########
+# End of "non-game-specific code"
 
 
 @defer.inlineCallbacks
@@ -128,10 +126,11 @@ def main(reactor):
         TargetCounter.web_server(
             reactor=reactor,
             engine=engine,
-            description="tcp:8080"
+            description="tcp:8080",
         )
         yield twisted_engine_loop(engine)
 
+
 if __name__ == "__main__":
     import sys
     task.react(main, sys.argv[1:])

lint.sh

@@ -0,0 +1,5 @@
+#!/usr/bin/env bash
+source .common.sh
+
+run flake8 --version
+run flake8

ppb/__init__.py

@@ -2,7 +2,7 @@
 from typing import Callable
 
 from ppb_vector import Vector
-from ppb.engine import GameEngine
+from ppb.engine import GameEngine  # noqa: I100
 from ppb.scenes import BaseScene
 from ppb.sprites import BaseSprite
 
@@ -25,7 +25,8 @@ def _make_kwargs(setup, title):
     }
     return kwargs
 
-def run(setup: Callable[[BaseScene], None]=None, *, log_level=logging.WARNING,
+
+def run(setup: Callable[[BaseScene], None] = None, *, log_level=logging.WARNING,
         starting_scene=BaseScene, title="PursuedPyBear"):
     """
     Run a small game.
@@ -45,6 +46,6 @@ def run(setup: Callable[[BaseScene], None]=None, *, log_level=logging.WARNING,
         eng.run()
 
 
-def make_engine(setup: Callable[[BaseScene], None]=None, *,
+def make_engine(setup: Callable[[BaseScene], None] = None, *,
                 starting_scene=BaseScene, title="PursedPyBear"):
     return GameEngine(starting_scene, **_make_kwargs(setup, title))

ppb/abc.py

@@ -1,4 +1,4 @@
-from typing import Type, Container, Tuple, Iterable
+from typing import Iterable, Tuple, Type
 
 
 class Engine(object):

ppb/camera.py

@@ -1,17 +1,17 @@
-from typing import Sequence
-from typing import Union
 from numbers import Number
+from typing import Sequence
 
 from ppb import Vector
-from ppb.sprites import BaseSprite
 from ppb.flags import DoNotRender
+from ppb.sprites import BaseSprite
+
 
 class Camera(BaseSprite):
 
     image = DoNotRender
 
-    def __init__(self, viewport: Sequence[int]=(0, 0, 800, 600),
-                 pixel_ratio: float=64):
+    def __init__(self, viewport: Sequence[int] = (0, 0, 800, 600),
+                 pixel_ratio: float = 64):
         """
 
         viewport: A container of origin x, origin y, width, and
@@ -64,6 +64,7 @@ def half_height(self) -> float:
     @property
     def half_width(self) -> float:
         return self.frame_width / 2
+
     @property
     def viewport_width(self) -> int:
         return self._viewport_width
@@ -82,25 +83,26 @@ def viewport_height(self, value: int):
         self._viewport_height = value
         self.viewport_offset = Vector(self.viewport_width / 2, value / 2)
 
-    def point_in_viewport(self, point:Vector) -> bool:
+    def point_in_viewport(self, point: Vector) -> bool:
         px, py = point
         vpx, vpy = self.viewport_origin
         vpw = self.viewport_width
         vph = self.viewport_height
-        return vpx <= px <= (vpw+vpx) and vpy <= py <= (vph+vpy)
+        return vpx <= px <= (vpw + vpx) and vpy <= py <= (vph + vpy)
 
     def in_frame(self, sprite: BaseSprite) -> bool:
-        return (self.frame_left <= sprite.right and
-                self.frame_right >= sprite.left and
-                self.frame_top <= sprite.bottom and
-                self.frame_bottom >= sprite.top
-                )
+        return (
+            self.frame_left <= sprite.right and
+            self.frame_right >= sprite.left and
+            self.frame_top <= sprite.bottom and
+            self.frame_bottom >= sprite.top
+        )
 
     def translate_to_frame(self, point: Vector) -> Vector:
         """
         Converts a vector from pixel-based window to in-game coordinate space
         """
-        offset = (point - self.viewport_offset) * (1/self.pixel_ratio)
+        offset = (point - self.viewport_offset) * (1 / self.pixel_ratio)
         loc = self.position + offset
         return loc.update(y=-loc.y)
 

ppb/engine.py

@@ -1,8 +1,8 @@
+import time
 from collections import defaultdict
 from collections import deque
 from contextlib import ExitStack
 from itertools import chain
-import time
 from typing import Any
 from typing import Callable
 from typing import DefaultDict
@@ -12,9 +12,7 @@
 
 import ppb.events as events
 from ppb.abc import Engine
-from ppb.events import StartScene
-from ppb.events import EventMixin
-from ppb.events import Quit
+from ppb.events import EventMixin, Quit, StartScene
 from ppb.systems import PygameEventPoller
 from ppb.systems import Renderer
 from ppb.systems import Updater
@@ -40,7 +38,8 @@ def __init__(self, first_scene: Type, *,
         # Engine State
         self.scenes = []
         self.events = deque()
-        self.event_extensions: DefaultDict[Union[Type, _ellipsis], List[Callable[[Any], None]]] = defaultdict(list)
+        self.event_extensions: DefaultDict[Union[Type, _ellipsis],
+                                           List[Callable[[Any], None]]] = defaultdict(list)
         self.running = False
         self.entered = False
         self._last_idle_time = None

ppb/events.py

@@ -1,17 +1,17 @@
-from dataclasses import dataclass
 import logging
 import re
+from dataclasses import dataclass
 from typing import Any
 from typing import Collection
 from typing import Dict
 from typing import Set
 from typing import Type
 from typing import Union
 
+from ppb import Vector
 from ppb.abc import Scene
 from ppb.buttons import MouseButton
 from ppb.keycodes import KeyCode
-from ppb import Vector
 
 __all__ = (
     'StartScene',
@@ -31,6 +31,7 @@
 boundaries_finder = re.compile('(.)([A-Z][a-z]+)')
 boundaries_finder_2 = re.compile('([a-z0-9])([A-Z])')
 
+
 def camel_to_snake(txt):
     s1 = boundaries_finder.sub(r'\1_\2', txt)
     return boundaries_finder_2.sub(r'\1_\2', s1).lower()
@@ -46,9 +47,10 @@ def __init__(self, instance, method, event):
         article = ['a', 'an'][int(e_name.lower()[0] in "aeiou")]
 
         message = f"""
-{o_name}.{method}() signature incorrect, it should accept {article} {e_name} object and a signal function.
+The signature of {o_name}.{method}() is incorrect:
+it should accept {article} {e_name} object and a signal function.
 
-{e_name} is a dataclass that represents an event. Its attributes 
+{e_name} is a dataclass that represents an event. Its attributes
 tell you about the event.
 
 The signal function is a function you can call that accepts an event instance

ppb/features/animation.py

@@ -3,8 +3,8 @@
 
 Only supports frame-by-frame, not gif, apng, or full motion video.
 """
-import time
 import re
+import time
 
 FILE_PATTERN = re.compile(r'\{(\d+)\.\.(\d+)\}')
 

ppb/flags.py

@@ -27,7 +27,7 @@ class FlagMeta(type):
     """
     Metaclass for Flag. You probably want that instead.
     """
-    def __new__(mcls, *p, abstract=False, **kw):
+    def __new__(mcls, *p, abstract=False, **kw):  # noqa: N804
         cls = super().__new__(mcls, *p, **kw)
         if abstract:
             cls._instance = ...