Commit Graph

13 Commits

Author SHA1 Message Date
Jeff Epler 52540a9830 Rename EXTENDED_FIELDS -> MP_TYPE_EXTENDED_FIELDS 2021-07-12 06:57:59 -05:00
Jeff Epler 7302bc09a7 rename the type flag to EXTENDED for consistency 2021-07-09 14:59:37 -05:00
Jeff Epler 0d756066e8 milestone: coverage make test_full passes 2021-07-06 10:37:32 -05:00
Jeff Epler df56ba207f WIP 2021-07-06 09:25:56 -05:00
Jeff Epler 87d3740c64 Merge tag 'v1.16' 2021-06-18 10:54:19 -05:00
Damien George 514bf1a191 extmod/uasyncio: Fix race with cancelled task waiting on finished task.
This commit fixes a problem with a race between cancellation of task A and
completion of task B, when A waits on B.  If task B completes just before
task A is cancelled then the cancellation of A does not work.  Instead,
the CancelledError meant to cancel A gets passed through to B (that's
expected behaviour) but B handles it as a "Task exception wasn't retrieved"
scenario, printing out such a message (this is because finished tasks point
their "coro" attribute to themselves to indicate they are done, and
implement the throw() method, but that method inadvertently catches the
CancelledError).  The correct behaviour is for B to bounce that
CancelledError back out.

This bug is mainly seen when wait_for() is used, and in that context the
symptoms are:
- occurs when using wait_for(T, S), if the task T being waited on finishes
  at exactly the same time as the wait-for timeout S expires
- task T will have run to completion
- the "Task exception wasn't retrieved message" is printed with
  "<class 'CancelledError'>" as the error (ie no traceback)
- the wait_for(T, S) call never returns (it's never put back on the
  uasyncio run queue) and all tasks waiting on this are blocked forever
  from running
- uasyncio otherwise continues to function and other tasks continue to be
  scheduled as normal

The fix here reworks the "waiting" attribute of Task to be called "state"
and uses it to indicate whether a task is: running and not awaited on,
running and awaited on, finished and not awaited on, or finished and
awaited on.  This means the task does not need to point "coro" to itself to
indicate finished, and also allows removal of the throw() method.

A benefit of this is that "Task exception wasn't retrieved" messages can go
back to being able to print the name of the coroutine function.

Fixes issue #7386.

Signed-off-by: Damien George <damien@micropython.org>
2021-06-16 13:02:37 +10:00
Scott Shawcroft e02a26453c
Merge MicroPython 1.14 into CircuitPython 2021-05-11 15:07:40 -07:00
Scott Shawcroft f0bb26d70f
Merge MicroPython 1.13 into CircuitPython 2021-05-04 18:06:33 -07:00
Damien George 309dfe39e0 extmod/uasyncio: Add Task.done() method.
This is added because task.coro==None is no longer the way to detect if a
task is finished.  Providing a (CPython compatible) function for this
allows the implementation to be abstracted away.

Signed-off-by: Damien George <damien@micropython.org>
2020-12-02 12:07:06 +11:00
Damien George ca40eb0fda extmod/uasyncio: Delay calling Loop.call_exception_handler by 1 loop.
When a tasks raises an exception which is uncaught, and no other task
await's on that task, then an error message is printed (or a user function
called) via a call to Loop.call_exception_handler.  In CPython this call is
made when the Task object is freed (eg via reference counting) because it's
at that point that it is known that the exception that was raised will
never be handled.

MicroPython does not have reference counting and the current behaviour is
to deal with uncaught exceptions as early as possible, ie as soon as they
terminate the task.  But this can be undesirable because in certain cases
a task can start and raise an exception immediately (before any await is
executed in that task's coro) and before any other task gets a chance to
await on it to catch the exception.

This commit changes the behaviour so that tasks which end due to an
uncaught exception are scheduled one more time for execution, and if they
are not await'ed on by the next scheduling loop, then the exception handler
is called (eg the exception is printed out).

Signed-off-by: Damien George <damien@micropython.org>
2020-12-02 12:07:06 +11:00
Damien George 8e048d2548 all: Clean up error strings to use lowercase and change cannot to can't.
Now that error string compression is supported it's more important to have
consistent error string formatting (eg all lowercase English words,
consistent contractions).  This commit cleans up some of the strings to
make them more consistent.
2020-04-13 22:19:37 +10:00
Jim Mussared def76fe4d9 all: Use MP_ERROR_TEXT for all error messages. 2020-04-05 15:02:06 +10:00
Damien George bc009fdd62 extmod/uasyncio: Add optional implementation of core uasyncio in C.
Implements Task and TaskQueue classes in C, using a pairing-heap data
structure.  Using this reduces RAM use of each Task, and improves overall
performance of the uasyncio scheduler.
2020-03-26 01:25:45 +11:00