Try and import the right compat...

And remove all the nonsense you re-factored into PiPin...

gpiozero/pins/native.py

@@ -309,23 +309,16 @@ class NativePin(LocalPiPin):
         finally:
             self.when_changed = f
 
-    def _get_when_changed(self):
-        return self._when_changed
+    def _enable_event_detect(self):
+        self._change_thread = Thread(target=self._change_watch)
+        self._change_thread.daemon = True
+        self._change_event.clear()
+        self._change_thread.start()
 
-    def _set_when_changed(self, value):
-        if self._when_changed is None and value is not None:
-            self._when_changed = value
-            self._change_thread = Thread(target=self._change_watch)
-            self._change_thread.daemon = True
-            self._change_event.clear()
-            self._change_thread.start()
-        elif self._when_changed is not None and value is None:
-            self._change_event.set()
-            self._change_thread.join()
-            self._change_thread = None
-            self._when_changed = None
-        else:
-            self._when_changed = value
+    def _disable_event_detect(self):
+        self._change_event.set()
+        self._change_thread.join()
+        self._change_thread = None
 
     def _change_watch(self):
         offset = self._edge_offset
@@ -334,5 +327,5 @@ class NativePin(LocalPiPin):
         while not self._change_event.wait(0.001):
             if self.factory.mem[offset] & mask:
                 self.factory.mem[offset] = mask
-                self._when_changed()
+                self._call_when_changed()
 

gpiozero/pins/pi.py

@@ -12,7 +12,7 @@ from weakref import ref, proxy
 try:
     from weakref import WeakMethod
 except ImportError:
-    from .compat import WeakMethod
+    from ..compat import WeakMethod
 import warnings
 
 try:

gpiozero/pins/pigpiod.py

@@ -8,11 +8,6 @@ str = type('')
 
 import os
 from weakref import proxy
-from threading import RLock
-try:
-    from weakref import WeakMethod
-except ImportError:
-    from .compat import WeakMethod
 
 import pigpio
 
@@ -170,8 +165,6 @@ class PiGPIOPin(PiPin):
         self._pull = 'up' if factory.pi_info.pulled_up(self.address[-1]) else 'floating'
         self._pwm = False
         self._bounce = None
-        self._when_changed_lock = RLock()
-        self._when_changed = None
         self._callback = None
         self._edges = pigpio.EITHER_EDGE
         try:

gpiozero/pins/rpigpio.py

@@ -7,13 +7,6 @@ from __future__ import (
 str = type('')
 
 import warnings
-from types import MethodType
-from threading import RLock
-from weakref import ref
-try:
-    from weakref import WeakMethod
-except ImportError:
-    from .compat import WeakMethod
 
 from RPi import GPIO
 
@@ -97,8 +90,6 @@ class RPiGPIOPin(LocalPiPin):
         self._frequency = None
         self._duty_cycle = None
         self._bounce = -666
-        self._when_changed_lock = RLock()
-        self._when_changed = None
         self._edges = GPIO.BOTH
         GPIO.setup(self.number, GPIO.IN, self.GPIO_PULL_UPS[self._pull])
 

gpiozero/pins/rpio.py

@@ -8,11 +8,6 @@ str = type('')
 
 
 import warnings
-from threading import RLock
-try:
-    from weakref import WeakMethod
-except ImportError:
-    from .compat import WeakMethod
 
 import RPIO
 import RPIO.PWM
@@ -89,8 +84,6 @@ class RPIOPin(LocalPiPin):
         self._pwm = False
         self._duty_cycle = None
         self._bounce = None
-        self._when_changed_lock = RLock()
-        self._when_changed = None
         self._edges = 'both'
         try:
             RPIO.setup(self.number, RPIO.IN, self.GPIO_PULL_UPS[self._pull])