bpo-32591: Add native coroutine origin tracking (#5250)

* Add coro.cr_origin and sys.set_coroutine_origin_tracking_depth
* Use coroutine origin information in the unawaited coroutine warning
* Stop using set_coroutine_wrapper in asyncio debug mode
* In BaseEventLoop.set_debug, enable debugging in the correct thread

2 files changed, 50 insertions, 0 deletions

diff --git a/Doc/library/inspect.rst b/Doc/library/inspect.rst
index 6be28a2..147e802 100644
--- a/Doc/library/inspect.rst
+++ b/Doc/library/inspect.rst
@@ -34,6 +34,9 @@ provided as convenient choices for the second argument to :func:`getmembers`.
 They also help you determine when you can expect to find the following special
 attributes:
 
+.. this function name is too big to fit in the ascii-art table below
+.. |coroutine-origin-link| replace:: :func:`sys.set_coroutine_origin_tracking_depth`
+
 +-----------+-------------------+---------------------------+
 | Type      | Attribute         | Description               |
 +===========+===================+===========================+
@@ -215,6 +218,10 @@ attributes:
 +-----------+-------------------+---------------------------+
 |           | cr_code           | code                      |
 +-----------+-------------------+---------------------------+
+|           | cr_origin         | where coroutine was       |
+|           |                   | created, or ``None``. See |
+|           |                   | |coroutine-origin-link|   |
++-----------+-------------------+---------------------------+
 | builtin   | __doc__           | documentation string      |
 +-----------+-------------------+---------------------------+
 |           | __name__          | original name of this     |
@@ -234,6 +241,9 @@ attributes:
    The ``__name__`` attribute of generators is now set from the function
    name, instead of the code name, and it can now be modified.
 
+.. versionchanged:: 3.7
+
+   Add ``cr_origin`` attribute to coroutines.
 
 .. function:: getmembers(object[, predicate])
 
diff --git a/Doc/library/sys.rst b/Doc/library/sys.rst
index 957d02b..54281a3 100644
--- a/Doc/library/sys.rst
+++ b/Doc/library/sys.rst
@@ -675,6 +675,18 @@ always available.
       for details.)
 
 
+.. function:: get_coroutine_origin_tracking_depth()
+
+   Get the current coroutine origin tracking depth, as set by
+   func:`set_coroutine_origin_tracking_depth`.
+
+   .. versionadded:: 3.7
+
+   .. note::
+      This function has been added on a provisional basis (see :pep:`411`
+      for details.)  Use it only for debugging purposes.
+
+
 .. function:: get_coroutine_wrapper()
 
    Returns ``None``, or a wrapper set by :func:`set_coroutine_wrapper`.
@@ -686,6 +698,10 @@ always available.
       This function has been added on a provisional basis (see :pep:`411`
       for details.)  Use it only for debugging purposes.
 
+   .. deprecated:: 3.7
+      The coroutine wrapper functionality has been deprecated, and
+      will be removed in 3.8. See :issue:`32591` for details.
+
 
 .. data:: hash_info
 
@@ -1212,6 +1228,26 @@ always available.
       This function has been added on a provisional basis (see :pep:`411`
       for details.)
 
+.. function:: set_coroutine_origin_tracking_depth(depth)
+
+   Allows enabling or disabling coroutine origin tracking. When
+   enabled, the ``cr_origin`` attribute on coroutine objects will
+   contain a tuple of (filename, line number, function name) tuples
+   describing the traceback where the coroutine object was created,
+   with the most recent call first. When disabled, ``cr_origin`` will
+   be None.
+
+   To enable, pass a *depth* value greater than zero; this sets the
+   number of frames whose information will be captured. To disable,
+   pass set *depth* to zero.
+
+   This setting is thread-specific.
+
+   .. versionadded:: 3.7
+
+   .. note::
+      This function has been added on a provisional basis (see :pep:`411`
+      for details.)  Use it only for debugging purposes.
 
 .. function:: set_coroutine_wrapper(wrapper)
 
@@ -1252,6 +1288,10 @@ always available.
       This function has been added on a provisional basis (see :pep:`411`
       for details.)  Use it only for debugging purposes.
 
+   .. deprecated:: 3.7
+      The coroutine wrapper functionality has been deprecated, and
+      will be removed in 3.8. See :issue:`32591` for details.
+
 .. function:: _enablelegacywindowsfsencoding()
 
    Changes the default filesystem encoding and errors mode to 'mbcs' and