PEP 479 wraps a StopIteration raised from a generator/coroutine into a
RuntimeError. CPython sets both __cause__ and __context__ of the new
RuntimeError to the original StopIteration (the same object). RustPython's
wrapping sites set __cause__ only, leaving __context__ as None.
set___cause__ already toggles __suppress_context__ to true, so the
user-facing traceback is unchanged — only assertions that inspect
__context__ directly observe the gap.
Three sites all wrap StopIteration / StopAsyncIteration into RuntimeError
for PEP 479. Set __context__ to the same exception instance before
setting __cause__ at each:
- frame.rs::StopIterationError intrinsic (generator yield-expression path)
- coroutine.rs generator __next__ StopIteration branch
- coroutine.rs async-generator __anext__ StopAsyncIteration branch
PyBaseExceptionRef is Arc-backed, so e.clone() is a refcount bump;
'cause is context' holds, matching CPython.
Unmasks:
- test_generator_stop.TestPEP479.test_stopiteration_wrapping_context
- test_yield_from.TestInterestingEdgeCases.test_close_and_throw_work
- test_yield_from.TestInterestingEdgeCases.test_close_and_throw_raise_stop_iteration
- test_yield_from.TestInterestingEdgeCases.test_close_and_throw_yield
This directory contains all of the Python files that make up the standard
library for RustPython.
Most of these files are copied over from the CPython repository (the 3.7
branch), with slight modifications to allow them to work under RustPython. The
current goal is to complete the standard library with as few modifications as
possible. Current modifications are just temporary workarounds for bugs/missing
feature within the RustPython implementation.
The first big module we are targeting is unittest, so we can leverage the
CPython test suite.
Changjoon
6b67067e9a