514bf1a191
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> |
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| .. | ||
| basics | ||
| cmdline | ||
| cpydiff | ||
| esp32 | ||
| extmod | ||
| feature_check | ||
| float | ||
| import | ||
| inlineasm | ||
| internal_bench | ||
| io | ||
| jni | ||
| micropython | ||
| misc | ||
| multi_bluetooth | ||
| multi_net | ||
| net_hosted | ||
| net_inet | ||
| perf_bench | ||
| pyb | ||
| pybnative | ||
| qemu-arm | ||
| stress | ||
| thread | ||
| unicode | ||
| unix | ||
| wipy | ||
| README | ||
| run-internalbench.py | ||
| run-multitests.py | ||
| run-natmodtests.py | ||
| run-perfbench.py | ||
| run-tests-exp.py | ||
| run-tests-exp.sh | ||
| run-tests.py | ||
This directory contains tests for various functionality areas of MicroPython. To run all stable tests, run "run-tests.py" script in this directory. Tests of capabilities not supported on all platforms should be written to check for the capability being present. If it is not, the test should merely output 'SKIP' followed by the line terminator, and call sys.exit() to raise SystemExit, instead of attempting to test the missing capability. The testing framework (run-tests.py in this directory, test_main.c in qemu_arm) recognizes this as a skipped test. There are a few features for which this mechanism cannot be used to condition a test. The run-tests.py script uses small scripts in the feature_check directory to check whether each such feature is present, and skips the relevant tests if not. Tests are generally verified by running the test both in MicroPython and in CPython and comparing the outputs. If the output differs the test fails and the outputs are saved in a .out and a .exp file respectively. For tests that cannot be run in CPython, for example because they use the machine module, a .exp file can be provided next to the test's .py file. A convenient way to generate that is to run the test, let it fail (because CPython cannot run it) and then copy the .out file (but not before checking it manually!) When creating new tests, anything that relies on float support should go in the float/ subdirectory. Anything that relies on import x, where x is not a built-in module, should go in the import/ subdirectory.