Get rid of __context__, per the latest changes to PEP 343 and python-dev

discussion.
There are two places of documentation that still mention __context__:
Doc/lib/libstdtypes.tex -- I wasn't quite sure how to rewrite that without
spending a whole lot of time thinking about it; and whatsnew, which Andrew
usually likes to change himself.

8 files changed, 19 insertions, 105 deletions

diff --git a/Lib/calendar.py b/Lib/calendar.py
index 7800aae..00948ef 100644
--- a/Lib/calendar.py
+++ b/Lib/calendar.py
@@ -484,9 +484,6 @@ class TimeEncoding:
     def __init__(self, locale):
         self.locale = locale
 
-    def __context__(self):
-        return self
-
     def __enter__(self):
         self.oldlocale = locale.setlocale(locale.LC_TIME, self.locale)
         return locale.getlocale(locale.LC_TIME)[1]
diff --git a/Lib/compiler/pycodegen.py b/Lib/compiler/pycodegen.py
index f25b3fb..d5d68aa 100644
--- a/Lib/compiler/pycodegen.py
+++ b/Lib/compiler/pycodegen.py
@@ -833,8 +833,6 @@ class CodeGenerator:
         self.__with_count += 1
         self.set_lineno(node)
         self.visit(node.expr)
-        self.emit('LOAD_ATTR', '__context__')
-        self.emit('CALL_FUNCTION', 0)
         self.emit('DUP_TOP')
         self.emit('LOAD_ATTR', '__exit__')
         self._implicitNameOp('STORE', exitvar)
diff --git a/Lib/contextlib.py b/Lib/contextlib.py
index 4e3b9c2..9d2c6a3 100644
--- a/Lib/contextlib.py
+++ b/Lib/contextlib.py
@@ -10,9 +10,6 @@ class GeneratorContext(object):
     def __init__(self, gen):
         self.gen = gen
 
-    def __context__(self):
-        return self
-
     def __enter__(self):
         try:
             return self.gen.next()
@@ -88,7 +85,7 @@ def contextfactory(func):
 
 
 @contextfactory
-def nested(*contexts):
+def nested(*managers):
     """Support multiple context managers in a single with-statement.
 
     Code like this:
@@ -109,8 +106,7 @@ def nested(*contexts):
     exc = (None, None, None)
     try:
         try:
-            for context in contexts:
-                mgr = context.__context__()
+            for mgr in managers:
                 exit = mgr.__exit__
                 enter = mgr.__enter__
                 vars.append(enter())
@@ -152,8 +148,6 @@ class closing(object):
     """
     def __init__(self, thing):
         self.thing = thing
-    def __context__(self):
-        return self
     def __enter__(self):
         return self.thing
     def __exit__(self, *exc_info):
diff --git a/Lib/decimal.py b/Lib/decimal.py
index 875e38a..2f989a8 100644
--- a/Lib/decimal.py
+++ b/Lib/decimal.py
@@ -2248,7 +2248,7 @@ class Context(object):
         s.append('traps=[' + ', '.join([t.__name__ for t, v in self.traps.items() if v]) + ']')
         return ', '.join(s) + ')'
 
-    def __context__(self):
+    def context_manager(self):
         return WithStatementContext(self.copy())
 
     def clear_flags(self):
diff --git a/Lib/dummy_thread.py b/Lib/dummy_thread.py
index d69d840..21fd03f 100644
--- a/Lib/dummy_thread.py
+++ b/Lib/dummy_thread.py
@@ -118,9 +118,6 @@ class LockType(object):
     def __exit__(self, typ, val, tb):
         self.release()
 
-    def __context__(self):
-        return self
-
     def release(self):
         """Release the dummy lock."""
         # XXX Perhaps shouldn't actually bother to test?  Could lead
diff --git a/Lib/test/test_contextlib.py b/Lib/test/test_contextlib.py
index 53f23b2..8d3dd1a 100644
--- a/Lib/test/test_contextlib.py
+++ b/Lib/test/test_contextlib.py
@@ -51,7 +51,7 @@ class ContextManagerTestCase(unittest.TestCase):
         @contextfactory
         def whee():
             yield
-        ctx = whee().__context__()
+        ctx = whee()
         ctx.__enter__()
         # Calling __exit__ should not result in an exception
         self.failIf(ctx.__exit__(TypeError, TypeError("foo"), None))
@@ -63,7 +63,7 @@ class ContextManagerTestCase(unittest.TestCase):
                 yield
             except:
                 yield
-        ctx = whoo().__context__()
+        ctx = whoo()
         ctx.__enter__()
         self.assertRaises(
             RuntimeError, ctx.__exit__, TypeError, TypeError("foo"), None
@@ -152,8 +152,6 @@ class NestedTestCase(unittest.TestCase):
         def a():
             yield 1
         class b(object):
-            def __context__(self):
-                return self
             def __enter__(self):
                 return 2
             def __exit__(self, *exc_info):
@@ -341,12 +339,12 @@ class DecimalContextTestCase(unittest.TestCase):
         orig_context = ctx.copy()
         try:
             ctx.prec = save_prec = decimal.ExtendedContext.prec + 5
-            with decimal.ExtendedContext:
+            with decimal.ExtendedContext.context_manager():
                 self.assertEqual(decimal.getcontext().prec,
                                  decimal.ExtendedContext.prec)
             self.assertEqual(decimal.getcontext().prec, save_prec)
             try:
-                with decimal.ExtendedContext:
+                with decimal.ExtendedContext.context_manager():
                     self.assertEqual(decimal.getcontext().prec,
                                      decimal.ExtendedContext.prec)
                     1/0
diff --git a/Lib/test/test_with.py b/Lib/test/test_with.py
index 7adb05e..765bfec 100644
--- a/Lib/test/test_with.py
+++ b/Lib/test/test_with.py
@@ -17,15 +17,10 @@ from test.test_support import run_unittest
 class MockContextManager(GeneratorContext):
     def __init__(self, gen):
         GeneratorContext.__init__(self, gen)
-        self.context_called = False
         self.enter_called = False
         self.exit_called = False
         self.exit_args = None
 
-    def __context__(self):
-        self.context_called = True
-        return GeneratorContext.__context__(self)
-
     def __enter__(self):
         self.enter_called = True
         return GeneratorContext.__enter__(self)
@@ -60,21 +55,17 @@ def mock_contextmanager_generator():
 
 class Nested(object):
 
-    def __init__(self, *contexts):
-        self.contexts = contexts
+    def __init__(self, *managers):
+        self.managers = managers
         self.entered = None
 
-    def __context__(self):
-        return self
-
     def __enter__(self):
         if self.entered is not None:
             raise RuntimeError("Context is not reentrant")
         self.entered = deque()
         vars = []
         try:
-            for context in self.contexts:
-                mgr = context.__context__()
+            for mgr in self.managers:
                 vars.append(mgr.__enter__())
                 self.entered.appendleft(mgr)
         except:
@@ -99,17 +90,12 @@ class Nested(object):
 
 
 class MockNested(Nested):
-    def __init__(self, *contexts):
-        Nested.__init__(self, *contexts)
-        self.context_called = False
+    def __init__(self, *managers):
+        Nested.__init__(self, *managers)
         self.enter_called = False
         self.exit_called = False
         self.exit_args = None
 
-    def __context__(self):
-        self.context_called = True
-        return Nested.__context__(self)
-
     def __enter__(self):
         self.enter_called = True
         return Nested.__enter__(self)
@@ -126,24 +112,8 @@ class FailureTestCase(unittest.TestCase):
             with foo: pass
         self.assertRaises(NameError, fooNotDeclared)
 
-    def testContextAttributeError(self):
-        class LacksContext(object):
-            def __enter__(self):
-                pass
-
-            def __exit__(self, type, value, traceback):
-                pass
-
-        def fooLacksContext():
-            foo = LacksContext()
-            with foo: pass
-        self.assertRaises(AttributeError, fooLacksContext)
-
     def testEnterAttributeError(self):
         class LacksEnter(object):
-            def __context__(self):
-                pass
-
             def __exit__(self, type, value, traceback):
                 pass
 
@@ -154,9 +124,6 @@ class FailureTestCase(unittest.TestCase):
 
     def testExitAttributeError(self):
         class LacksExit(object):
-            def __context__(self):
-                pass
-
             def __enter__(self):
                 pass
 
@@ -192,27 +159,10 @@ class FailureTestCase(unittest.TestCase):
             'with mock as (foo, None, bar):\n'
             '  pass')
 
-    def testContextThrows(self):
-        class ContextThrows(object):
-            def __context__(self):
-                raise RuntimeError("Context threw")
-
-        def shouldThrow():
-            ct = ContextThrows()
-            self.foo = None
-            with ct as self.foo:
-                pass
-        self.assertRaises(RuntimeError, shouldThrow)
-        self.assertEqual(self.foo, None)
-
     def testEnterThrows(self):
         class EnterThrows(object):
-            def __context__(self):
-                return self
-
             def __enter__(self):
-                raise RuntimeError("Context threw")
-
+                raise RuntimeError("Enter threw")
             def __exit__(self, *args):
                 pass
 
@@ -226,8 +176,6 @@ class FailureTestCase(unittest.TestCase):
 
     def testExitThrows(self):
         class ExitThrows(object):
-            def __context__(self):
-                return self
             def __enter__(self):
                 return
             def __exit__(self, *args):
@@ -241,13 +189,11 @@ class ContextmanagerAssertionMixin(object):
     TEST_EXCEPTION = RuntimeError("test exception")
 
     def assertInWithManagerInvariants(self, mock_manager):
-        self.assertTrue(mock_manager.context_called)
         self.assertTrue(mock_manager.enter_called)
         self.assertFalse(mock_manager.exit_called)
         self.assertEqual(mock_manager.exit_args, None)
 
     def assertAfterWithManagerInvariants(self, mock_manager, exit_args):
-        self.assertTrue(mock_manager.context_called)
         self.assertTrue(mock_manager.enter_called)
         self.assertTrue(mock_manager.exit_called)
         self.assertEqual(mock_manager.exit_args, exit_args)
@@ -268,7 +214,6 @@ class ContextmanagerAssertionMixin(object):
         raise self.TEST_EXCEPTION
 
     def assertAfterWithManagerInvariantsWithError(self, mock_manager):
-        self.assertTrue(mock_manager.context_called)
         self.assertTrue(mock_manager.enter_called)
         self.assertTrue(mock_manager.exit_called)
         self.assertEqual(mock_manager.exit_args[0], RuntimeError)
@@ -472,7 +417,6 @@ class ExceptionalTestCase(unittest.TestCase, ContextmanagerAssertionMixin):
 
         # The inner statement stuff should never have been touched
         self.assertEqual(self.bar, None)
-        self.assertFalse(mock_b.context_called)
         self.assertFalse(mock_b.enter_called)
         self.assertFalse(mock_b.exit_called)
         self.assertEqual(mock_b.exit_args, None)
@@ -506,13 +450,9 @@ class ExceptionalTestCase(unittest.TestCase, ContextmanagerAssertionMixin):
         self.assertRaises(StopIteration, shouldThrow)
 
     def testRaisedStopIteration2(self):
-        class cm (object):
-            def __context__(self):
-                return self
-
+        class cm(object):
             def __enter__(self):
                 pass
-
             def __exit__(self, type, value, traceback):
                 pass
 
@@ -535,12 +475,8 @@ class ExceptionalTestCase(unittest.TestCase, ContextmanagerAssertionMixin):
 
     def testRaisedGeneratorExit2(self):
         class cm (object):
-            def __context__(self):
-                return self
-
             def __enter__(self):
                 pass
-
             def __exit__(self, type, value, traceback):
                 pass
 
@@ -629,7 +565,6 @@ class AssignmentTargetTestCase(unittest.TestCase):
 
     def testMultipleComplexTargets(self):
         class C:
-            def __context__(self): return self
             def __enter__(self): return 1, 2, 3
             def __exit__(self, t, v, tb): pass
         targets = {1: [0, 1, 2]}
@@ -651,7 +586,6 @@ class ExitSwallowsExceptionTestCase(unittest.TestCase):
 
     def testExitTrueSwallowsException(self):
         class AfricanSwallow:
-            def __context__(self): return self
             def __enter__(self): pass
             def __exit__(self, t, v, tb): return True
         try:
@@ -662,7 +596,6 @@ class ExitSwallowsExceptionTestCase(unittest.TestCase):
 
     def testExitFalseDoesntSwallowException(self):
         class EuropeanSwallow:
-            def __context__(self): return self
             def __enter__(self): pass
             def __exit__(self, t, v, tb): return False
         try:
diff --git a/Lib/threading.py b/Lib/threading.py
index 27ec6b4..c27140d 100644
--- a/Lib/threading.py
+++ b/Lib/threading.py
@@ -90,9 +90,6 @@ class _RLock(_Verbose):
                 self.__owner and self.__owner.getName(),
                 self.__count)
 
-    def __context__(self):
-        return self
-
     def acquire(self, blocking=1):
         me = currentThread()
         if self.__owner is me:
@@ -182,8 +179,11 @@ class _Condition(_Verbose):
             pass
         self.__waiters = []
 
-    def __context__(self):
-        return self.__lock.__context__()
+    def __enter__(self):
+        return self.__lock.__enter__()
+
+    def __exit__(self, *args):
+        return self.__lock.__exit__(*args)
 
     def __repr__(self):
         return "<Condition(%s, %d)>" % (self.__lock, len(self.__waiters))
@@ -278,9 +278,6 @@ class _Semaphore(_Verbose):
         self.__cond = Condition(Lock())
         self.__value = value
 
-    def __context__(self):
-        return self
-
     def acquire(self, blocking=1):
         rc = False
         self.__cond.acquire()