Don't leak the injector instance into the class.

README.rst

@@ -137,8 +137,8 @@ method, annotate ``__init__`` and access the value via `self`.
 Collects dependencies and reads annotations to inject them.
 
 
-``Injector.__init__(self, provide_self=False)``
------------------------------------------------
+``Injector.__init__(self, provide_self=True)``
+----------------------------------------------
 
 A subclass could take arguments, but should pass keywords to super.
 
@@ -155,17 +155,23 @@ or providing alternative dependencies in a different runtime::
     class Injector(BaseInjector):
         "Subclass provides namespace when registering providers."
 
-By default, the injector does not provide itself, but will when asked::
+Injector instances may be used as a context manager::
 
-    injector = Injector(provide_self=True)
-    injector.get('injector')
+    with Injector() as injector:
+        injector.apply(annotated_fn)
 
-This is useful in a context manager::
+The injector lifecycle can also be managed asynchronously using the
+`enter()` and `exit()` methods::
 
-    with Injector(provide_self=True) as injector:
-        injector.get('injector')
+    injector = Injector().enter()
+    injector.apply(annotated_fn)
+    ...
+    injector.exit()
 
-Annotate with note 'injector' to inject the injector.
+The injector provides itself as the `'injector'` service::
+
+    with Injector() as injector:
+        injector.get('injector')
 
 
 ``Injector.sub(cls, *mixins_and_dicts, **values)``

jeni.py

@@ -11,6 +11,7 @@
 import functools
 import inspect
 import re
+import warnings
 import sys
 
 import six
@@ -365,7 +366,7 @@ class Injector(object):
     generator_provider = GeneratorProvider
     re_note = re.compile(r'^(.*?)(?::(.*))?$') # annotation is 'object:name'
 
-    def __init__(self, provide_self=False):
+    def __init__(self, provide_self=True):
         """A subclass could take arguments, but should pass keywords to super.
 
         An Injector subclass inherits the provider registry of its base
@@ -381,20 +382,24 @@ def __init__(self, provide_self=False):
             class Injector(BaseInjector):
                 "Subclass provides namespace when registering providers."
 
-        By default, the injector does not provide itself, but will when asked::
+        Injector instances may be used as a context manager::
 
-            injector = Injector(provide_self=True)
-            injector.get('injector')
+            with Injector() as injector:
+                injector.apply(annotated_fn)
 
-        This is useful in a context manager::
+        The injector lifecycle can also be managed asynchronously using the
+        `enter()` and `exit()` methods::
 
-            with Injector(provide_self=True) as injector:
-                injector.get('injector')
+            injector = Injector().enter()
+            injector.apply(annotated_fn)
+            ...
+            injector.exit()
+
+        The injector provides itself as the `'injector'` service::
 
-        Annotate with note 'injector' to inject the injector.
+            with Injector() as injector:
+                injector.get('injector')
         """
-        if provide_self:
-            self.value('injector', self)
 
         self.annotator = self.annotator_class()
 
@@ -412,6 +417,12 @@ class Injector(BaseInjector):
         #: This allows for dependency cycle checks.
         self.instantiating = []
 
+        if provide_self:
+            self.values['injector'] = self
+        else:
+            warnings.warn(
+                    DeprecationWarning('provide_self=False is not supported'))
+
     @classmethod
     def provider(cls, note, provider=None, name=False):
         """Register a provider, either a Provider class or a generator.

test_jeni.py

@@ -155,7 +155,7 @@ class SubInjector(BasicInjector):
 class InjectSelfTestCase(unittest.TestCase):
     def test_provide_self_default(self):
         self.injector = jeni.Injector()
-        self.assertRaises(LookupError, self.injector.get, 'injector')
+        self.assertEqual(self.injector, self.injector.get('injector'))
 
     def test_provide_self_true(self):
         self.injector = jeni.Injector(provide_self=True)
@@ -165,6 +165,12 @@ def test_provide_self_false(self):
         self.injector = jeni.Injector(provide_self=False)
         self.assertRaises(LookupError, self.injector.get, 'injector')
 
+    def test_provide_self_is_self(self):
+        injector1 = jeni.Injector(provide_self=True)
+        injector2 = jeni.Injector(provide_self=True)
+        self.assertEqual(injector1, injector1.get('injector'))
+        self.assertEqual(injector2, injector2.get('injector'))
+
 
 class SubInjectorTestCase(BasicInjectorTestCase):
     def setUp(self):
@@ -221,6 +227,10 @@ def test_subinjector_mixins(self):
         self.assertIsInstance(subinjector, WithOrderedSpace)
         self.assertIsInstance(subinjector.get('space'), odict)
 
+    def test_subinjector_provides_injector(self):
+        subinjector = self.injector.sub()
+        self.assertEqual(subinjector, subinjector.get('injector'))
+
 
 class BasicInjectorAnnotationTestCase(unittest.TestCase):
     def setUp(self):