Adds a "threadsafe" variant of `PyCell::try_borrow` which will fail instead of
panicking if called on the wrong thread and use it in `call_traverse` to turn GC
traversals of unsendable pyclasses into no-ops if on the wrong thread.
This can imply leaking the underlying resource if the originator thread has
already exited so that the GC will never run there again, but it does avoid hard
aborts as we cannot raise an exception from within `call_traverse`.
3209: Remove the conditional compilation flags which are made redundant by the MSRV bump r=davidhewitt a=adamreichold
Co-authored-by: Adam Reichold <adam.reichold@t-online.de>
3203: support ordering magic methods for `#[pyclass]` r=adamreichold a=davidhewitt
Closes#2089
This adds `__lt__`, `__le__`, `__eq__`, `__ne__`, `__gt__`, and `__ge__` as per the Python implementations of what we call `__richcmp__`.
There's a UI test confirming that the user cannot implement split forms and `__richcmp__` simultaneously.
There's also a benchmark comparing implementing these split methods against using `__richcmp__`. I couldn't see a meaningful performance difference, so I'm tempted to deprecate `__richcmp__`, given that's not a magic method which exists in Python. Potentially we can provide options such as the opt-in `#[pyclass(eq, ord)]` to avoid boilerplate for people who don't want to implement six different methods.
Co-authored-by: David Hewitt <1939362+davidhewitt@users.noreply.github.com>
3171: RFC: Simplify version handling of UI tests. r=davidhewitt a=adamreichold
Due to checking in error outputs these tests only work reliably on stable and not on intermediate version between our MSRV (currently 1.48) and the current stable version.
Hence this simplifies things to run only MSRV-compatible tests for the MSRV builds, anything else for stable builds except for those tests which require the nightly feature, i.e. the `Ungil` being distinct from the `Send` trait.
Finally, `not_send3` is disabled when using the nightly feature since while `Rc` is not send, it also not GIL-bound and hence can be passed into `allow_threads` as it does not actually spawn a new thread.
Co-authored-by: Adam Reichold <adam.reichold@t-online.de>
Due to checking in error outputs these tests only work reliably on stable and
not on intermediate version between our MSRV (currently 1.48) and the current
stable version.
Hence this simplifies things to run only MSRV-compatible tests for the MSRV
builds, anything else for stable builds except for those tests which require the
nightly feature, i.e. the `Ungil` being distinct from the `Send` trait.
Finally, `not_send3` is disabled when using the nightly feature since while `Rc`
is not send, it also not GIL-bound and hence can be passed into `allow_threads`
as it does not actually spawn a new thread.
3168: Do not apply deferred ref count updates and prevent the GIL from being acquired inside of __traverse__ implementations. r=davidhewitt a=adamreichold
Closes#2301Closes#3165
3176: Prevent dropping unsendable classes on other threads. r=davidhewitt a=adamreichold
Continuing the discussed from https://github.com/PyO3/pyo3/pull/3169#issuecomment-1556571504 and https://github.com/PyO3/pyo3/pull/3169#issuecomment-1556661723:
We already have checks in place to avoid borrowing these classes on other threads but it was still possible to send them to another thread and drop them there (while holding the GIL).
This change avoids running the `Drop` implementation in such a case even though Python will still free the underlying memory. This might leak resources owned by the object, but it avoids undefined behaviour due to access the unsendable type from another thread.
This does assume that the object was not unsafely integrated into an intrusive data structures which still point to the now freed memory. In that case, the only recourse would be to abort the process as freeing the memory is unavoidable when the tp_dealloc slot is called. (And moving it elsewhere into a new allocation would still break any existing pointers.)
Co-authored-by: Adam Reichold <adam.reichold@t-online.de>
We already have checks in place to avoid borrowing these classes on other
threads but it was still possible to send them to another thread and drop them
there (while holding the GIL).
This change avoids running the `Drop` implementation in such a case even though
Python will still free the underlying memory. This might leak resources owned by
the object, but it avoids undefined behaviour due to access the unsendable type
from another thread.
This does assume that the object was not unsafely integrated into an intrusive
data structures which still point to the now freed memory. In that case, the
only recourse would be to abort the process as freeing the memory is unavoidable
when the tp_dealloc slot is called. (And moving it elsewhere into a new
allocation would still break any existing pointers.)
David Hewitt