You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
142 lines
5.9 KiB
Plaintext
142 lines
5.9 KiB
Plaintext
Metadata-Version: 2.1
|
|
Name: exceptiongroup
|
|
Version: 1.0.4
|
|
Summary: Backport of PEP 654 (exception groups)
|
|
Author-email: Alex Grönholm <alex.gronholm@nextday.fi>
|
|
Requires-Python: >=3.7
|
|
Description-Content-Type: text/x-rst
|
|
Classifier: Development Status :: 5 - Production/Stable
|
|
Classifier: Intended Audience :: Developers
|
|
Classifier: License :: OSI Approved :: MIT License
|
|
Classifier: Programming Language :: Python
|
|
Classifier: Programming Language :: Python :: 3 :: Only
|
|
Classifier: Typing :: Typed
|
|
Requires-Dist: pytest >= 6 ; extra == "test"
|
|
Project-URL: Changelog, https://github.com/agronholm/exceptiongroup/blob/main/CHANGES.rst
|
|
Project-URL: Issue Tracker, https://github.com/agronholm/exceptiongroup/issues
|
|
Project-URL: Source code, https://github.com/agronholm/exceptiongroup
|
|
Provides-Extra: test
|
|
|
|
.. image:: https://github.com/agronholm/exceptiongroup/actions/workflows/test.yml/badge.svg
|
|
:target: https://github.com/agronholm/exceptiongroup/actions/workflows/test.yml
|
|
:alt: Build Status
|
|
.. image:: https://coveralls.io/repos/github/agronholm/exceptiongroup/badge.svg?branch=main
|
|
:target: https://coveralls.io/github/agronholm/exceptiongroup?branch=main
|
|
:alt: Code Coverage
|
|
|
|
This is a backport of the ``BaseExceptionGroup`` and ``ExceptionGroup`` classes from
|
|
Python 3.11.
|
|
|
|
It contains the following:
|
|
|
|
* The ``exceptiongroup.BaseExceptionGroup`` and ``exceptiongroup.ExceptionGroup``
|
|
classes
|
|
* A utility function (``exceptiongroup.catch()``) for catching exceptions possibly
|
|
nested in an exception group
|
|
* Patches to the ``TracebackException`` class that properly formats exception groups
|
|
(installed on import)
|
|
* An exception hook that handles formatting of exception groups through
|
|
``TracebackException`` (installed on import)
|
|
* Special versions of some of the functions from the ``traceback`` module, modified to
|
|
correctly handle exception groups even when monkey patching is disabled, or blocked by
|
|
another custom exception hook:
|
|
|
|
* ``traceback.format_exception()``
|
|
* ``traceback.format_exception_only()``
|
|
* ``traceback.print_exception()``
|
|
* ``traceback.print_exc()``
|
|
|
|
If this package is imported on Python 3.11 or later, the built-in implementations of the
|
|
exception group classes are used instead, ``TracebackException`` is not monkey patched
|
|
and the exception hook won't be installed.
|
|
|
|
See the `standard library documentation`_ for more information on exception groups.
|
|
|
|
.. _standard library documentation: https://docs.python.org/3/library/exceptions.html
|
|
|
|
Catching exceptions
|
|
===================
|
|
|
|
Due to the lack of the ``except*`` syntax introduced by `PEP 654`_ in earlier Python
|
|
versions, you need to use ``exceptiongroup.catch()`` to catch exceptions that are
|
|
potentially nested inside an exception group. This function returns a context manager
|
|
that calls the given handler for any exceptions matching the sole argument.
|
|
|
|
The argument to ``catch()`` must be a dict (or any ``Mapping``) where each key is either
|
|
an exception class or an iterable of exception classes. Each value must be a callable
|
|
that takes a single positional argument. The handler will be called at most once, with
|
|
an exception group as an argument which will contain all the exceptions that are any
|
|
of the given types, or their subclasses. The exception group may contain nested groups
|
|
containing more matching exceptions.
|
|
|
|
Thus, the following Python 3.11+ code:
|
|
|
|
.. code-block:: python3
|
|
|
|
try:
|
|
...
|
|
except* (ValueError, KeyError) as excgroup:
|
|
for exc in excgroup.exceptions:
|
|
print('Caught exception:', type(exc))
|
|
except* RuntimeError:
|
|
print('Caught runtime error')
|
|
|
|
would be written with this backport like this:
|
|
|
|
.. code-block:: python3
|
|
|
|
from exceptiongroup import ExceptionGroup, catch
|
|
|
|
def value_key_err_handler(excgroup: ExceptionGroup) -> None:
|
|
for exc in excgroup.exceptions:
|
|
print('Caught exception:', type(exc))
|
|
|
|
def runtime_err_handler(exc: ExceptionGroup) -> None:
|
|
print('Caught runtime error')
|
|
|
|
with catch({
|
|
(ValueError, KeyError): value_key_err_handler,
|
|
RuntimeError: runtime_err_handler
|
|
}):
|
|
...
|
|
|
|
**NOTE**: Just like with ``except*``, you cannot handle ``BaseExceptionGroup`` or
|
|
``ExceptionGroup`` with ``catch()``.
|
|
|
|
Notes on monkey patching
|
|
========================
|
|
|
|
To make exception groups render properly when an unhandled exception group is being
|
|
printed out, this package does two things when it is imported on any Python version
|
|
earlier than 3.11:
|
|
|
|
#. The ``traceback.TracebackException`` class is monkey patched to store extra
|
|
information about exception groups (in ``__init__()``) and properly format them (in
|
|
``format()``)
|
|
#. An exception hook is installed at ``sys.excepthook``, provided that no other hook is
|
|
already present. This hook causes the exception to be formatted using
|
|
``traceback.TracebackException`` rather than the built-in rendered.
|
|
|
|
If ``sys.exceptionhook`` is found to be set to something else than the default when
|
|
``exceptiongroup`` is imported, no monkeypatching is done at all.
|
|
|
|
To prevent the exception hook and patches from being installed, set the environment
|
|
variable ``EXCEPTIONGROUP_NO_PATCH`` to ``1``.
|
|
|
|
Formatting exception groups
|
|
---------------------------
|
|
|
|
Normally, the monkey patching applied by this library on import will cause exception
|
|
groups to be printed properly in tracebacks. But in cases when the monkey patching is
|
|
blocked by a third party exception hook, or monkey patching is explicitly disabled,
|
|
you can still manually format exceptions using the special versions of the ``traceback``
|
|
functions, like ``format_exception()``, listed at the top of this page. They work just
|
|
like their counterparts in the ``traceback`` module, except that they use a separately
|
|
patched subclass of ``TracebackException`` to perform the rendering.
|
|
|
|
Particularly in cases where a library installs its own exception hook, it is recommended
|
|
to use these special versions to do the actual formatting of exceptions/tracebacks.
|
|
|
|
.. _PEP 654: https://www.python.org/dev/peps/pep-0654/
|
|
|