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Upgrade Cython to version 3

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While looking at #333, I hypothesized that upgrading Cython might solve the
issue. It didn't. But upgrading should still happen at some point. This is my
work in progress on that. The tests pass, but there are two main things missing:

Problem (1):
Starting with Cython 3, you can only do `except+` or `except
+reraise_kj_exception` on `extern` functions coming from C++. (This makes sense,
and the way things were declared in Pycapnp wasn't too good.) As a result, I had
to remove a lot of these declaration. This results in some segmentation faults,
because Cython no longer detects C++ exceptions and converts them to Python
exceptions in some places.

To solve this, all `extern` declarations in `.pxd` files have to be examined and
`except +reraise_kj_exception` clauses need to be added to anything that might
throw. Previously, this was done really inconsistently. The lazy solution would
be to just add the clause everywhere, but I'm not sure what the performance
implications are.

Problem (2):
The compilation output of `python setup.py build_ext --inplace` is now full of messages like these:
```
capnp/lib/capnp.cpp: In function ‘PyObject* __pyx_f_5capnp_3lib_5capnp_18_DynamicListReader__get(__pyx_obj_5capnp_3lib_5capnp__DynamicListReader*, int64_t, int)’:
capnp/lib/capnp.cpp:4871:51: warning: moving a temporary object prevents copy elision [-Wpessimizing-move]
 4871 |   #define __PYX_STD_MOVE_IF_SUPPORTED(x) std::move(x)
      |                                          ~~~~~~~~~^~~
capnp/lib/capnp.cpp:20944:59: note: in expansion of macro ‘__PYX_STD_MOVE_IF_SUPPORTED’
20944 |   __pyx_t_2 = __pyx_f_5capnp_3lib_5capnp_to_python_reader(__PYX_STD_MOVE_IF_SUPPORTED((( ::capnp::DynamicValue::Reader)__pyx_t_7)), __pyx_t_1); if (unlikely(!__pyx_t_2)) __PYX_ERR(0, 419, __pyx_L1_error)
      |                                                           ^~~~~~~~~~~~~~~~~~~~~~~~~~~
capnp/lib/capnp.cpp:4871:51: note: remove ‘std::move’ call
 4871 |   #define __PYX_STD_MOVE_IF_SUPPORTED(x) std::move(x)
      |                                          ~~~~~~~~~^~~
capnp/lib/capnp.cpp:20944:59: note: in expansion of macro ‘__PYX_STD_MOVE_IF_SUPPORTED’
20944 |   __pyx_t_2 = __pyx_f_5capnp_3lib_5capnp_to_python_reader(__PYX_STD_MOVE_IF_SUPPORTED((( ::capnp::DynamicValue::Reader)__pyx_t_7)), __pyx_t_1); if (unlikely(!__pyx_t_2)) __PYX_ERR(0, 419, __pyx_L1_error)
      |                                                           ^~~~~~~~~~~~~~~~~~~~~~~~~~~
```
There are to many `move` calls inserted. I'm not sure if this is a Cython issue,
or if we are somehow annotating things wrong. Might be worth asking the Cython
people.

I'm not planning on working on this further in the short term. If someone wants
to take over on this, feel free.
This commit is contained in:
Lasse Blaauwbroek
2023-10-13 11:33:28 +02:00
committed by Jacob Alexander
parent 59a639fa97
commit 983719fde9
9 changed files with 84 additions and 103 deletions
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12
capnp/includes/schema_cpp.pxd
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@@ -673,7 +673,7 @@ cdef extern from "capnp/message.h" namespace " ::capnp":
Annotation.Builder getRootAnnotation'getRoot< ::capnp::schema::Annotation>'()
Annotation.Builder initRootAnnotation'initRoot< ::capnp::schema::Annotation>'()
DynamicStruct_Builder getRootDynamicStruct'getRoot< ::capnp::DynamicStruct>'(StructSchema)
DynamicStruct_Builder getRootDynamicStruct'getRoot< ::capnp::DynamicStruct>'(StructSchema) except +reraise_kj_exception
DynamicStruct_Builder initRootDynamicStruct'initRoot< ::capnp::DynamicStruct>'(StructSchema)
void setRootDynamicStruct'setRoot< ::capnp::DynamicStruct::Reader>'(DynamicStruct.Reader)
@@ -696,7 +696,7 @@ cdef extern from "capnp/message.h" namespace " ::capnp":
StructNode.Reader getRootStructNode'getRoot< ::capnp::schema::StructNode>'()
Annotation.Reader getRootAnnotation'getRoot< ::capnp::schema::Annotation>'()
DynamicStruct.Reader getRootDynamicStruct'getRoot< ::capnp::DynamicStruct>'(StructSchema)
DynamicStruct.Reader getRootDynamicStruct'getRoot< ::capnp::DynamicStruct>'(StructSchema) except +reraise_kj_exception
AnyPointer.Reader getRootAnyPointer'getRoot< ::capnp::AnyPointer>'()
cdef cppclass MallocMessageBuilder(MessageBuilder) nogil:
@@ -798,7 +798,7 @@ cdef extern from "capnp/serialize.h" namespace " ::capnp":
FlatArrayMessageReader(WordArrayPtr array, ReaderOptions) except +reraise_kj_exception
const word* getEnd() const
void writeMessageToFd(int, MessageBuilder&) nogil except +reraise_kj_exception
void writeMessageToFd(int, MessageBuilder&) except +reraise_kj_exception nogil
WordArray messageToFlatArray(MessageBuilder &) nogil
@@ -816,6 +816,6 @@ cdef extern from "capnp/serialize-packed.h" namespace " ::capnp":
PackedFdMessageReader(int) except +reraise_kj_exception
PackedFdMessageReader(int, ReaderOptions) except +reraise_kj_exception
void writePackedMessage(BufferedOutputStream&, MessageBuilder&) nogil except +reraise_kj_exception
void writePackedMessage(OutputStream&, MessageBuilder&) nogil except +reraise_kj_exception
void writePackedMessageToFd(int, MessageBuilder&) nogil except +reraise_kj_exception
void writePackedMessage(BufferedOutputStream&, MessageBuilder&) except +reraise_kj_exception nogil
void writePackedMessage(OutputStream&, MessageBuilder&) except +reraise_kj_exception nogil
void writePackedMessageToFd(int, MessageBuilder&) except +reraise_kj_exception nogil