Warn deprecation in Promise.promisify instead of full deprecation.

promise/promise.py

@@ -9,7 +9,7 @@
 from .async_ import Async
 from .compat import (Future, ensure_future, iscoroutine,  # type: ignore
                      iterate_promise)
-from .utils import deprecated, integer_types, string_types, text_type, binary_type
+from .utils import deprecated, integer_types, string_types, text_type, binary_type, warn
 from .context import Context
 from .promise_list import PromiseList
 from .scheduler import SyncScheduler
@@ -680,6 +680,10 @@ def resolve(cls, obj):
 
     @classmethod
     def promisify(cls, f):
+        if not callable(f):
+            warn("Promise.promisify is now a function decorator, please use Promise.resolve instead.")
+            return cls.resolve(f)
+
         @wraps(f)
         def wrapper(*args, **kwargs):
             def executor(resolve, reject):

promise/utils.py

@@ -5,6 +5,12 @@
 import sys
 
 
+def warn(msg):
+    warnings.simplefilter('always', DeprecationWarning)  # turn off filter
+    warnings.warn(msg, category=DeprecationWarning, stacklevel=2)
+    warnings.simplefilter('default', DeprecationWarning)  # reset filter
+
+
 class deprecated(object):
 
     def __init__(self, reason, name=None):
@@ -27,9 +33,7 @@ def __call__(self, cls_or_func):
 
         @functools.wraps(cls_or_func)
         def new_func(*args, **kwargs):
-            warnings.simplefilter('always', DeprecationWarning)  # turn off filter
-            warnings.warn(msg, category=DeprecationWarning, stacklevel=2)
-            warnings.simplefilter('default', DeprecationWarning)  # reset filter
+            warn(msg)
             return cls_or_func(*args, **kwargs)
 
         return new_func