PyCode "Unparse": Added support for slice objects in subscriptions

[MatrixEditor]

Subject: Fix documentation issue when slice objects are used in subscriptions

Feature or Bugfix

• Feature

Purpose

• Added function to handle parsed slice objects

Detail

• For instance, consider the following class definition:

  class Foo: ...
  
  class Bar(BaseType):
      #: doc comment
      field1: int
      field2: Foo[1:2:3]
      """doc comment"""

  Internally, sphinx will raise an exception while parsing this file:

  ...
  File "venv-3.12/lib/python3.12/site-packages/sphinx/pycode/ast.py", line 170, in visit_Subscript
    return f"{self.visit(node.value)}[{self.visit(node.slice)}]"
                                       ^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/ast.py", line 407, in visit
    return visitor(node)
           ^^^^^^^^^^^^^
  File "venv-3.12/lib/python3.12/site-packages/sphinx/pycode/ast.py", line 188, in generic_visit
    raise NotImplementedError('Unable to parse %s object' % type(node).__name__)
  NotImplementedError: Unable to parse Slice object
  

• The implemented function does not alter existing code

Relates

• Support syntax def myfunc(arg: "float64[:,:]"): #10817

[picnixz]

Can you add tests and a CHANGES please?

[picnixz]

Just by looking at all those identity checks, I think we should have used a sentinel value, say IDENTICAL, to indicate that the output is the same as the input. This is an easy follow-up PR though.

[picnixz]

Actually, can you check that #10817 is indeed solved?

[MatrixEditor]

Yes, but that will take me a few moments.

[picnixz]

Don't worry, you're fast enough (it also allows me to work on something else in the meantime)

[MatrixEditor]

Yes, #10817 is indeed fixed:

temp/__init__.py

Ac = "float64[:, :]"


def myfunc(arg: Ac):
    """Some docs"""
    ...

index.rst

Welcome to temp's documentation!
================================

.. autofunction:: temp.myfunc


Indices and tables
==================

* :ref:`genindex`
* :ref:`modindex`
* :ref:`search`

Results in:

[picnixz]

Is it possible to include this one as a test as well?

[picnixz]

Thank you!