When `__getattr__` is implemented, attribute lookup will always fall back to that,
even if the initial failure comes from `__getattribute__` or a descriptor's `__get__`
method (including property methods).
The f-string example for using datetime format specifier does not match the given output.
Changed the format from %b to %B so it matches the output of "January".
Make it clear that setting __class__ on a module has worked since 3.5,
but support for __getattr__ and __dir__ on module instances requires 3.7+
Patch by Cheryl Sabella.
* Document `from __future__ import annotations`
* Provide plumbing and tests for `from __future__ import annotations`
* Implement unparsing the AST back to string form
This is required for PEP 563 and as such only implements a part of the
unparsing process that covers expressions.
In lexical analysis reference documentation, the internal link to
the string literal concatenation section was written as`.. _string-catenation:`.
Changed that to `.. _string-concatenation:`.
Python now supports checking bytecode cache up-to-dateness with a hash of the
source contents rather than volatile source metadata. See the PEP for details.
While a fairly straightforward idea, quite a lot of code had to be modified due
to the pervasiveness of pyc implementation details in the codebase. Changes in
this commit include:
- The core changes to importlib to understand how to read, validate, and
regenerate hash-based pycs.
- Support for generating hash-based pycs in py_compile and compileall.
- Modifications to our siphash implementation to support passing a custom
key. We then expose it to importlib through _imp.
- Updates to all places in the interpreter, standard library, and tests that
manually generate or parse pyc files to grok the new format.
- Support in the interpreter command line code for long options like
--check-hash-based-pycs.
- Tests and documentation for all of the above.
The current behaviour of yield expressions inside comprehensions and
generator expressions is essentially an accident of implementation - it
arises implicitly from the way the compiler handles yield expressions inside
nested functions and generators.
Since the current behaviour wasn't deliberately designed, and is inherently
confusing, we're deprecating it, with no current plans to reintroduce it.
Instead, our advice will be to use a named nested generator definition
for cases where this behaviour is desired.
async and await keywords has been merged into upstream, but they are
all missing in the lexical analysis docs. This change adds them to the
appropriate keywords section in documentation.
f_trace_lines: enable/disable line trace events
f_trace_opcodes: enable/disable opcode trace events
These are intended primarily for testing of the interpreter
itself, as they make it much easier to emulate signals
arriving at unfortunate times.
The data model section of the language reference was written well
before the zero-argument form of super() was added.
To avoid giving the impression that they're doing something
unusual, this updates the description of `__new__` and `__init__`
to use the zero-argument form.
Patch by Cheryl Sabella.
Builtin container types have two potential link targets in the docs:
- their entry in the list of builtin callables
- their type documentation
This change brings `bytes` and `bytearray` into line with other
container types by having cross-references default to linking to
their type documentation, rather than their builtin callable entry.
Issue #28383: __hash__ documentation recommends naive XOR to combine but this
is suboptimal. Update the doc to suggest to reuse the hash() method using a
tuple, with an example.
Handling zero-argument super() in __init_subclass__ and
__set_name__ involved moving __class__ initialisation to
type.__new__. This requires cooperation from custom
metaclasses to ensure that the new __classcell__ entry
is passed along appropriately.
The initial implementation of that change resulted in abruptly
broken zero-argument super() support in metaclasses that didn't
adhere to the new requirements (such as Django's metaclass for
Model definitions).
The updated approach adopted here instead emits a deprecation
warning for those cases, and makes them work the same way they
did in Python 3.5.
This patch also improves the related class machinery documentation
to cover these details and to include more reader-friendly
cross-references and index entries.
- Issue #25958: Support "anti-registration" of special methods from
various ABCs, like __hash__, __iter__ or __len__. All these (and
several more) can be set to None in an implementation class and the
behavior will be as if the method is not defined at all.
(Previously, this mechanism existed only for __hash__, to make
mutable classes unhashable.) Code contributed by Andrew Barnert and
Ivan Levkivskyi.
Serhiy Storchaka
Eric Appelt
Nick Coghlan
Cheryl Sabella
Guido van Rossum
İsmail Arılık
KatherineMichel
Antoine Pitrou
Mariatta
Ivan Levkivskyi
Benjamin Peterson
Berker Peksag
Tom Floyer
Barry Warsaw
Yury Selivanov
kms70847
Guilherme Caminha
svelankar
Louie Lu
Lisa Roach
Aaron Hall, MBA
Naomi Ceder
csabella
delirious-lettuce
Dominik Miedziński
Jim Fasarakis-Hilliard
UltimateCoder
Jelle Zijlstra
cocoatomo
Amit Kumar
Marco Buttu
Martin Panter
Victor Stinner
Jason R. Coombs
Raymond Hettinger
Guido van Rossum
Brett Cannon
Eric Snow
R David Murray