TypeError: unsupported format string passed to NoneType.__format__

[jacobtylerwalls]

Regression in #2459

Steps to reproduce

a.py:

class A:
    def __init__(self):
        self._magnitude = None

    def name(self) -> str | None:
        if self._magnitude:
            return f"M {self._magnitude:.1f}"

pylint a.py

Current behavior

  File "/Users/jwalls/release/lib/python3.12/site-packages/astroid/nodes/node_classes.py", line 4778, in _infer_from_values
    yield from nodes[0]._infer(context, **kwargs)
  File "/Users/jwalls/release/lib/python3.12/site-packages/astroid/nodes/node_classes.py", line 4695, in _infer
    formatted = format(value.value, format_spec.value)
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: unsupported format string passed to NoneType.__format__

[jacobtylerwalls]

@ericvergnaud would you be available to take a look at this?

[ericvergnaud]

@ericvergnaud would you be available to take a look at this?

Done, see #2496