autodoc_typehints='description' doesn't suppress signature type hints for classes/methods

[godlygeek]

Describe the bug

For functions, autodoc_typehints='description' prevents the type hints from being included in the signature in the generated documentation, but for methods and classes it doesn't. This is because FunctionDocumenter.format_args does:

        if self.env.config.autodoc_typehints in ('none', 'description'):
            kwargs.setdefault('show_annotation', False)

But ClassDocumenter.format_args and MethodDocumenter.format_args do only:

        if self.env.config.autodoc_typehints == 'none':
            kwargs.setdefault('show_annotation', False)

To Reproduce

mkdir -p sphinx_signature_type_hints
cd sphinx_signature_type_hints

cat <<'EOF' >type_hint_test.py
def times_5(x: int) -> int:
    """Multiplies *x* by 5.

    :param x: Value to multiply by 5
    :returns: *x* * 5
    """


class Multiplier:
    """Functor for multiplying by a constant.

    :param factor: Factor to multiply by.
    """
    def __init__(self, factor: int) -> None:
        self._factor = factor

    def multiply(self, x: int) -> int:
        """Multiplies *x* by this object's *factor*.

        :param x: Value to multiply
        :returns: *x* * *factor*
        """
        return x * self._factor
EOF

mkdir -p docs

cat <<'EOF' >docs/conf.py
extensions = ["sphinx.ext.autodoc"]
autodoc_typehints = 'description'
EOF

cat <<'EOF' >docs/index.rst
.. automodule:: type_hint_test
    :members:
EOF

mkdir -p html
python3.8 -m sphinx -vvv -W -b html --keep-going docs html

Expected behavior

autodoc_typehints='description' doesn't put type hints into the signature; only autodoc_typehints='signature' does.

Environment info

• OS: Linux 4.4.0
• Python version: 3.8.1
• Sphinx version: 3.0.0
• Sphinx extensions: sphinx.ext.autodoc, sphinx.ext.intersphinx

Additional context

The generated reST from the above reproducer is:

.. py:module:: type_hint_test


.. py:class:: Multiplier(factor: int)
   :module: type_hint_test

   Functor for multiplying by a constant.

   :param factor: Factor to multiply by.


   .. py:method:: Multiplier.multiply(x: int) -> int
      :module: type_hint_test

      Multiplies *x* by this object's *factor*.

      :param x: Value to multiply
      :returns: *x* * *factor*


.. py:function:: times_5(x)
   :module: type_hint_test

   Multiplies *x* by 5.

   :param x: Value to multiply by 5
   :returns: *x* * 5

Note that the py:class and py:method have type hints in the signature, but the py:function doesn't.

[tk0miya]

OMG. I'll fix this in next release.