The dict type has multiple methods which use METH_VARARGS or METH_VARARGS|METH_KEYWORDS calling convention, whereras there is no a new faster METH_FASTCALL calling convention which avoids temporary tuple/dict to pass arguments.

dict.patch converts two methods to Argument Clinic:

* get()
* setdefault()

pop() requires the issue #29299, its signature must not show any default value for the second parameter.

dict.update() is special, so I created a dedicated issue: issue #29312.

LGTM

New changeset 00c63ee66e0c by Victor Stinner in branch 'default':
dict.get() and dict.setdefault() now use AC
https://hg.python.org/cpython/rev/00c63ee66e0c

New changeset fe1d83fe29d6 by Serhiy Storchaka in branch 'default':
Issue #29311: Argument Clinic generates reasonable name for the parameter "default".
https://hg.python.org/cpython/rev/fe1d83fe29d6

There are same problems with docstrings as in OrderedDict. The name "D" is not defined.

> Argument Clinic generates reasonable name for the parameter "default".
> -    default as failobj: object = None
> +    default: object = None

Thanks, that's a better name :-)

FYI I wanted to limit changes when converting to AC, the change is already big enough and hard to review.

> There are same problems with docstrings as in OrderedDict. The name "D" is not defined.

I copied the old docstring to AC.

Python 3.6 doc:
---
get(...)
    D.get(k[,d]) -> D[k] if k in D, else d.  d defaults to None.
---

D was already implicitly "self".


Python 3.7 (new) doc:
---
get(self, key, default=None, /)
    D.get(key[, default]) -> D[key] if key in D, else default.
---

What do you propose? Use self?

There was a context in old docstrings removed in new docstrings.

It is not always possible just to copy docstrings in Argument Clinic. Sometimes rewriting docstrings is the hardest part of converting to Argument Clinic.

I suggest either restore the context that defines D, or better totally rewrite docstrings, getting the wording from the documentation.

D.get(key[, default]) -> D[key] if key in D, else default.

There is no big problem with that. D is defined at the start. The only thing I would have suggested is avoid using square brackets to mean two things in the one expression. Since it is no longer the signature, calling with both parameters should be okay:

'''
get($self, key, default=None, /)
--
D.get(key, default) -> D[key] if key in D, else default.
'''

However the other method no longer defines D:

'''
setdefault($self, key, default=None, /)
--
D.get(key,default), also set D[key]=default if key not in D.
'''

You could restore the initial text as “D.setdefault(key,default) ->”, or maybe rewrite it like

“Like get(), but also insert the default value if it is missing.”

Proposed patch fixes/improves docstrings of dict and OrderedDict methods.

Patch looks good, apart from one little thing (see review)

New changeset ffc0840762e4 by Serhiy Storchaka in branch 'default':
Issues #29311, #29289: Fixed and improved docstrings for dict and OrderedDict
https://hg.python.org/cpython/rev/ffc0840762e4

Thank you for your review Martin.

Thank you very much for the docstring enhancement Serhiy! I like your new docstrings.

It seems like all known issues are now fixed, so I close the issue. Thanks Naoki and Martin too for the reviews.

New changeset 222b9392a83b by Serhiy Storchaka in branch 'default':
Issue #29311: Regenerate Argument Clinic.
https://hg.python.org/cpython/rev/222b9392a83b

New changeset 7baf0a0b90da5bb0b1ed5d27374f5a6b1c7b5dae by Serhiy Storchaka in branch 'master':
Issue #29311: Regenerate Argument Clinic.
https://github.com/python/cpython/commit/7baf0a0b90da5bb0b1ed5d27374f5a6b1c7b5dae

IMO, you've made the docstrings for pure Python versions of collections.OrderedDict worse.  The previous docstrings were clearer.

Please note, there is a high bar for altering docstrings that have worked well (been deployed with success) for over 15 years (they were modeled on the dict object docstrings).  You're undoing some of the work originally done by Guido van Rossum and Tim Peters.

Argument clinic was accepted on the premise that it would add useful information, not that it would entail a wholesale rewrite of every docstring.

> IMO, you've made the docstrings for pure Python versions of collections.OrderedDict worse.  The previous docstrings were clearer.

Can you please elaborate? Please reopen the issue or open a new one if you consider that it's worth it (this issue is currently closed).