green selectors: Remove non-green selectors

The code pretending that all the selector classes exist and
"implementing" them using SelectSelector was added in [1] because there
was no facility to easily remove things from green version of modules
(as far as I understand) - the facility has been added in [2] thus
allowing us to make this change.

As mentioned in the code I believe this approach is likely to be less
confusing than the previous one (SelectSelector doesn't expose fileno()
method that the other selectors have so it's not fully API-compatible
with them).

[1] 0d509ef7d2
[2] f63165c0e3

eventlet/green/selectors.py

@@ -5,6 +5,18 @@ from eventlet.green import select
 
 __patched__ = [
     'SelectSelector',
+]
+
+# We only have green select so the options are:
+# * leave it be and have selectors that block
+# * try to pretend the "bad" selectors don't exist
+# * replace all with SelectSelector for the price of possibly different
+#   performance characteristic and missing fileno() method (if someone
+#   uses it it'll result in a crash, we may want to implement it in the future)
+#
+# This module used to follow the third approach but just removing the offending
+# selectors is less error prone and less confusing approach.
+__deleted__ = [
     'PollSelector',
     'EpollSelector',
     'DevpollSelector',
@@ -17,15 +29,3 @@ del patcher
 
 if sys.platform != 'win32':
     SelectSelector._select = staticmethod(select.select)
-
-
-# We only have green select so the options are:
-# * leave it be and have selectors that block
-# * try to pretend the "bad" selectors don't exist
-# * replace all with SelectSelector for the price of possibly different
-#   performance characteristic and missing fileno() method (if someone
-#   uses it it'll result in a crash, we may want to implement it in the future)
-PollSelector = SelectSelector
-EpollSelector = SelectSelector
-DevpollSelector = SelectSelector
-KqueueSelector = SelectSelector

tests/isolated/patcher_blocking_select_methods_are_deleted.py

@@ -12,4 +12,16 @@ if __name__ == '__main__':
     for name in ['poll', 'epoll', 'kqueue', 'kevent']:
         assert not hasattr(select, name), name
 
+    import sys
+
+    if sys.version_info >= (3, 4):
+        import selectors
+        for name in [
+            'PollSelector',
+            'EpollSelector',
+            'DevpollSelector',
+            'KqueueSelector',
+        ]:
+            assert not hasattr(selectors, name), name
+
     print('pass')