f'"{var:}"' adds redundant empty string literal in AST in 3.12 #106396
Description
3.11:
>>> import ast >>> print(ast.dump(ast.parse("""f'"{var:}"'"""), indent=2)) Module( body=[ Expr( value=JoinedStr( values=[ Constant(value='"'), FormattedValue( value=Name(id='var', ctx=Load()), conversion=-1, format_spec=JoinedStr(values=[])), Constant(value='"')]))], type_ignores=[])3.12:
>>> import ast >>> print(ast.dump(ast.parse("""f'"{var:}"'"""), indent=2)) Module( body=[ Expr( value=JoinedStr( values=[ Constant(value='"'), FormattedValue( value=Name(id='var', ctx=Load()), conversion=-1, format_spec=JoinedStr( values=[ Constant(value='')])), Constant(value='"')]))], type_ignores=[])This affects several linters:
- Fix parse test case on Python 3.12 mypy#15577
- B907 crashes when bugbear is run on Python 3.12 PyCQA/flake8-bugbear#393
Is this a bug? Or is it a feature?