Merge tag 'python-pull-request' of https://gitlab.com/jsnow/qemu into staging

Pull request

# gpg: Signature made Wed 17 Nov 2021 01:33:06 AM CET
# gpg:                using RSA key F9B7ABDBBCACDF95BE76CBD07DEF8106AAFC390E
# gpg: Good signature from "John Snow (John Huston) <jsnow@redhat.com>" [full]

* tag 'python-pull-request' of https://gitlab.com/jsnow/qemu:
  scripts/device-crash-test: hide tracebacks for QMP connect errors
  scripts/device-crash-test: don't emit AQMP connection errors to stdout
  scripts/device-crash-test: simplify Exception handling
  python/aqmp: fix ConnectError string method
  python/aqmp: Fix disconnect during capabilities negotiation

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

1 files changed, 18 insertions, 6 deletions

diff --git a/python/qemu/aqmp/protocol.py b/python/qemu/aqmp/protocol.py
index ae1df24026..5190b33b13 100644
--- a/python/qemu/aqmp/protocol.py
+++ b/python/qemu/aqmp/protocol.py
@@ -79,7 +79,11 @@ class ConnectError(AQMPError):
         self.exc: Exception = exc
 
     def __str__(self) -> str:
-        return f"{self.error_message}: {self.exc!s}"
+        cause = str(self.exc)
+        if not cause:
+            # If there's no error string, use the exception name.
+            cause = exception_summary(self.exc)
+        return f"{self.error_message}: {cause}"
 
 
 class StateError(AQMPError):
@@ -623,13 +627,21 @@ class AsyncProtocol(Generic[T]):
         def _done(task: Optional['asyncio.Future[Any]']) -> bool:
             return task is not None and task.done()
 
-        # NB: We can't rely on _bh_tasks being done() here, it may not
-        #     yet have had a chance to run and gather itself.
+        # Are we already in an error pathway? If either of the tasks are
+        # already done, or if we have no tasks but a reader/writer; we
+        # must be.
+        #
+        # NB: We can't use _bh_tasks to check for premature task
+        # completion, because it may not yet have had a chance to run
+        # and gather itself.
         tasks = tuple(filter(None, (self._writer_task, self._reader_task)))
         error_pathway = _done(self._reader_task) or _done(self._writer_task)
+        if not tasks:
+            error_pathway |= bool(self._reader) or bool(self._writer)
 
         try:
-            # Try to flush the writer, if possible:
+            # Try to flush the writer, if possible.
+            # This *may* cause an error and force us over into the error path.
             if not error_pathway:
                 await self._bh_flush_writer()
         except BaseException as err:
@@ -639,7 +651,7 @@ class AsyncProtocol(Generic[T]):
             self.logger.debug("%s:\n%s\n", emsg, pretty_traceback())
             raise
         finally:
-            # Cancel any still-running tasks:
+            # Cancel any still-running tasks (Won't raise):
             if self._writer_task is not None and not self._writer_task.done():
                 self.logger.debug("Cancelling writer task.")
                 self._writer_task.cancel()
@@ -652,7 +664,7 @@ class AsyncProtocol(Generic[T]):
                 self.logger.debug("Waiting for tasks to complete ...")
                 await asyncio.wait(tasks)
 
-            # Lastly, close the stream itself. (May raise):
+            # Lastly, close the stream itself. (*May raise*!):
             await self._bh_close_stream(error_pathway)
             self.logger.debug("Disconnected.")