python: backport 'drop Python3.6 workarounds'

Now that the minimum version is 3.7, drop some of the 3.6-specific hacks
we've been carrying. A single remaining compatibility hack concerning
3.6's lack of @asynccontextmanager is addressed in the following commit.

Signed-off-by: John Snow <jsnow@redhat.com>
cherry picked from commit python-qemu-qmp@3e8e34e594cfc6b707e6f67959166acde4b421b8
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

1 files changed, 4 insertions, 103 deletions

diff --git a/python/qemu/qmp/util.py b/python/qemu/qmp/util.py
index ca6225e9cd..0b3e781373 100644
--- a/python/qemu/qmp/util.py
+++ b/python/qemu/qmp/util.py
@@ -1,25 +1,15 @@
 """
 Miscellaneous Utilities
 
-This module provides asyncio utilities and compatibility wrappers for
-Python 3.6 to provide some features that otherwise become available in
-Python 3.7+.
-
-Various logging and debugging utilities are also provided, such as
-`exception_summary()` and `pretty_traceback()`, used primarily for
-adding information into the logging stream.
+This module provides asyncio and various logging and debugging
+utilities, such as `exception_summary()` and `pretty_traceback()`, used
+primarily for adding information into the logging stream.
 """
 
 import asyncio
 import sys
 import traceback
-from typing import (
-    Any,
-    Coroutine,
-    Optional,
-    TypeVar,
-    cast,
-)
+from typing import TypeVar, cast
 
 
 T = TypeVar('T')
@@ -79,95 +69,6 @@ def bottom_half(func: T) -> T:
     return func
 
 
-# -------------------------------
-# Section: Compatibility Wrappers
-# -------------------------------
-
-
-def create_task(coro: Coroutine[Any, Any, T],
-                loop: Optional[asyncio.AbstractEventLoop] = None
-                ) -> 'asyncio.Future[T]':
-    """
-    Python 3.6-compatible `asyncio.create_task` wrapper.
-
-    :param coro: The coroutine to execute in a task.
-    :param loop: Optionally, the loop to create the task in.
-
-    :return: An `asyncio.Future` object.
-    """
-    if sys.version_info >= (3, 7):
-        if loop is not None:
-            return loop.create_task(coro)
-        return asyncio.create_task(coro)  # pylint: disable=no-member
-
-    # Python 3.6:
-    return asyncio.ensure_future(coro, loop=loop)
-
-
-def is_closing(writer: asyncio.StreamWriter) -> bool:
-    """
-    Python 3.6-compatible `asyncio.StreamWriter.is_closing` wrapper.
-
-    :param writer: The `asyncio.StreamWriter` object.
-    :return: `True` if the writer is closing, or closed.
-    """
-    if sys.version_info >= (3, 7):
-        return writer.is_closing()
-
-    # Python 3.6:
-    transport = writer.transport
-    assert isinstance(transport, asyncio.WriteTransport)
-    return transport.is_closing()
-
-
-async def wait_closed(writer: asyncio.StreamWriter) -> None:
-    """
-    Python 3.6-compatible `asyncio.StreamWriter.wait_closed` wrapper.
-
-    :param writer: The `asyncio.StreamWriter` to wait on.
-    """
-    if sys.version_info >= (3, 7):
-        await writer.wait_closed()
-        return
-
-    # Python 3.6
-    transport = writer.transport
-    assert isinstance(transport, asyncio.WriteTransport)
-
-    while not transport.is_closing():
-        await asyncio.sleep(0)
-
-    # This is an ugly workaround, but it's the best I can come up with.
-    sock = transport.get_extra_info('socket')
-
-    if sock is None:
-        # Our transport doesn't have a socket? ...
-        # Nothing we can reasonably do.
-        return
-
-    while sock.fileno() != -1:
-        await asyncio.sleep(0)
-
-
-def asyncio_run(coro: Coroutine[Any, Any, T], *, debug: bool = False) -> T:
-    """
-    Python 3.6-compatible `asyncio.run` wrapper.
-
-    :param coro: A coroutine to execute now.
-    :return: The return value from the coroutine.
-    """
-    if sys.version_info >= (3, 7):
-        return asyncio.run(coro, debug=debug)
-
-    # Python 3.6
-    loop = asyncio.get_event_loop()
-    loop.set_debug(debug)
-    ret = loop.run_until_complete(coro)
-    loop.close()
-
-    return ret
-
-
 # ----------------------------
 # Section: Logging & Debugging
 # ----------------------------