bpo-39529: Deprecate creating new event loop in asyncio.get_event_loop() (GH-23554)

asyncio.get_event_loop() emits now a deprecation warning when it creates a new event loop.
In future releases it will became an alias of asyncio.get_running_loop().

1 files changed, 10 insertions, 1 deletions

diff --git a/Lib/asyncio/events.py b/Lib/asyncio/events.py
index 1a20f36..b966ad2 100644
--- a/Lib/asyncio/events.py
+++ b/Lib/asyncio/events.py
@@ -759,9 +759,16 @@ def get_event_loop():
     the result of `get_event_loop_policy().get_event_loop()` call.
     """
     # NOTE: this function is implemented in C (see _asynciomodule.c)
+    return _py__get_event_loop()
+
+
+def _get_event_loop(stacklevel=3):
     current_loop = _get_running_loop()
     if current_loop is not None:
         return current_loop
+    import warnings
+    warnings.warn('There is no current event loop',
+                  DeprecationWarning, stacklevel=stacklevel)
     return get_event_loop_policy().get_event_loop()
 
 
@@ -791,6 +798,7 @@ _py__get_running_loop = _get_running_loop
 _py__set_running_loop = _set_running_loop
 _py_get_running_loop = get_running_loop
 _py_get_event_loop = get_event_loop
+_py__get_event_loop = _get_event_loop
 
 
 try:
@@ -798,7 +806,7 @@ try:
     # functions in asyncio.  Pure Python implementation is
     # about 4 times slower than C-accelerated.
     from _asyncio import (_get_running_loop, _set_running_loop,
-                          get_running_loop, get_event_loop)
+                          get_running_loop, get_event_loop, _get_event_loop)
 except ImportError:
     pass
 else:
@@ -807,3 +815,4 @@ else:
     _c__set_running_loop = _set_running_loop
     _c_get_running_loop = get_running_loop
     _c_get_event_loop = get_event_loop
+    _c__get_event_loop = _get_event_loop