Issue #27558: Fix a SystemError in the implementation of "raise" statement.
In a brand new thread, raise a RuntimeError since there is no active
exception to reraise.
Patch written by Xiang Zhang.
Issue #27128, #18295: replace int type with Py_ssize_t for index variables used
for positional arguments. It should help to avoid integer overflow and help to
emit better machine code for "i++" (no trap needed for overflow).
Make also the total_args variable constant.
* Add comments
* Add empty lines for readability
* PEP 7 style for if block
* Remove useless assert(globals != NULL); (globals is tested a few lines
before)
Don't fallback to PyDict_GetItemWithError() if the hash is unknown: compute the
hash instead. Add also comments to explain the optimization a little bit.
requested name doesn't exist in globals: clear the KeyError exception before
calling PyObject_GetItem(). Fail also if the raised exception is not a
KeyError.
Summary of changes:
1. Coroutines now have a distinct, separate from generators
type at the C level: PyGen_Type, and a new typedef PyCoroObject.
PyCoroObject shares the initial segment of struct layout with
PyGenObject, making it possible to reuse existing generators
machinery. The new type is exposed as 'types.CoroutineType'.
As a consequence of having a new type, CO_GENERATOR flag is
no longer applied to coroutines.
2. Having a separate type for coroutines made it possible to add
an __await__ method to the type. Although it is not used by the
interpreter (see details on that below), it makes coroutines
naturally (without using __instancecheck__) conform to
collections.abc.Coroutine and collections.abc.Awaitable ABCs.
[The __instancecheck__ is still used for generator-based
coroutines, as we don't want to add __await__ for generators.]
3. Add new opcode: GET_YIELD_FROM_ITER. The opcode is needed to
allow passing native coroutines to the YIELD_FROM opcode.
Before this change, 'yield from o' expression was compiled to:
(o)
GET_ITER
LOAD_CONST
YIELD_FROM
Now, we use GET_YIELD_FROM_ITER instead of GET_ITER.
The reason for adding a new opcode is that GET_ITER is used
in some contexts (such as 'for .. in' loops) where passing
a coroutine object is invalid.
4. Add two new introspection functions to the inspec module:
getcoroutinestate(c) and getcoroutinelocals(c).
5. inspect.iscoroutine(o) is updated to test if 'o' is a native
coroutine object. Before this commit it used abc.Coroutine,
and it was requested to update inspect.isgenerator(o) to use
abc.Generator; it was decided, however, that inspect functions
should really be tailored for checking for native types.
6. sys.set_coroutine_wrapper(w) API is updated to work with only
native coroutines. Since types.coroutine decorator supports
any type of callables now, it would be confusing that it does
not work for all types of coroutines.
7. Exceptions logic in generators C implementation was updated
to raise clearer messages for coroutines:
Before: TypeError("generator raised StopIteration")
After: TypeError("coroutine raised StopIteration")
* adds missing INCREF in WITH_CLEANUP_START
* adds missing DECREF in WITH_CLEANUP_FINISH
* adds several new tests Yury created while investigating this
which returned an invalid result (result+error or no result without error) in
the exception message.
Add also unit test to check that the exception contains the name of the
function.
Special case: the final _PyEval_EvalFrameEx() check doesn't mention the
function since it didn't execute a single function but a whole frame.
raise a SystemError if a function returns a result and raises an exception.
The SystemError is chained to the previous exception.
Refactor also PyObject_Call() and PyCFunction_Call() to make them more readable.
Remove some checks which became useless (duplicate checks).
Change reviewed by Serhiy Storchaka.
At entry, save or swap the exception state even if PyEval_EvalFrameEx() is
called with throwflag=0. At exit, the exception state is now always restored or
swapped, not only if why is WHY_YIELD or WHY_RETURN. Patch co-written with
Antoine Pitrou.
name, and use it in the representation of a generator (``repr(gen)``). The
default name of the generator (``__name__`` attribute) is now get from the
function instead of the code. Use ``gen.gi_code.co_name`` to get the name of
the code.
crash when a generator is created in a C thread that is destroyed while the
generator is still used. The issue was that a generator contains a frame, and
the frame kept a reference to the Python state of the destroyed C thread. The
crash occurs when a trace function is setup.
with an assertion error if they are called with an exception set
(PyErr_Occurred()).
If these functions are called with an exception set, the exception may be
cleared and so the caller looses its exception.
Add also assertions to PyEval_CallObjectWithKeywords() and call_function() to
check if the function succeed with no exception set, or the function failed
with an exception set.
ImportError.
The exception is raised by import when a module could not be found.
Technically this is defined as no viable loader could be found for the
specified module. This includes ``from ... import`` statements so that
the module usage is consistent for all situations where import
couldn't find what was requested.
This should allow for the common idiom of::
try:
import something
except ImportError:
pass
to be updated to using ModuleNotFoundError and not accidentally mask
ImportError messages that should propagate (e.g. issues with a
loader).
This work was driven by the fact that the ``from ... import``
statement needed to be able to tell the difference between an
ImportError that simply couldn't find a module (and thus silence the
exception so that ceval can raise it) and an ImportError that
represented an actual problem.
Victor Stinner
Serhiy Storchaka
Martin Panter
Yury Selivanov
Benjamin Peterson
Yury Selivanov
Eric V. Smith
Brett Cannon
Nick Coghlan
R David Murray
Antoine Pitrou
Guido van Rossum
Christian Heimes
Victor Stinner