Fix __str__ call for all Python objects #342

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1. Ekopalypse commented on Jul 11, 2024

   

   Ekopalypse

   on Jul 11, 2024

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   Can you explain when this is a problem when using PythonScript?
2. tooruu commented on Jul 11, 2024

   

   tooruu

   on Jul 11, 2024

   Last edited by tooruu

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   Can you explain when this is a problem when using PythonScript?

   Let's take editor.write for example. Its C++ signature expects a boost::python::api::object.
   As I understand, we can pass any Python object and you convert it to string via ScintillaWrapper::getStringFromObject by calling o.__str__().
   This works because you usually pass an instantiated class object, meaning you don't need to manually pass self to its methods (like __str__), so a call without arguments works.
   But it breaks if you pass an uninstantiated class object (class itself). It doesn't bind self, so it expects you to pass something to the __str__ method.

   >>> editor.write('text')  # 'text'.__str__() == 'text'
   >>> editor.write(42)  # (42).__str__() == '42'

   So far it looks fine with instances of str and int class (return values are omitted for brevity). Let's try a custom class.

   >>> class Foo:
   ...     def __str__(self):
   ...         return __class__.__name__.lower()
   ...
   >>> editor.write(Foo())  # Foo().__str__() == 'foo'
   >>> editor.write(Foo)  # There is no `self` to auto insert into the `__str__` call.
   Traceback (most recent call last):
     File "<console>", line 1, in <module>
   TypeError: Foo.__str__() missing 1 required positional argument: 'self'

   One might expect the value of str(Foo) to be written into the editor, but it wants us to pass something to __str__.

   P.S. In this example str(Foo) == "<class '__main__.Foo'>". Not the most common use case, but you never know what the user is up to!

   >>> class Meta(type):
   ...     def __str__(cls):
   ...         return cls.__name__.upper()
   ... 
   >>> class Bar(metaclass=Meta):
   ...     pass
   ... 
   >>> str(Bar)
   'BAR'
   >>> editor.write(Bar)
   Traceback (most recent call last):
     File "<console>", line 1, in <module>
   TypeError: descriptor '__str__' of 'object' object needs an argument
3. Ekopalypse commented on Jul 12, 2024

   

   Ekopalypse

   on Jul 12, 2024

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   I understand what you mean, but usually PythonScript is used to manipulate Notepad++, Scintilla and the buffer content, but

   but you never know what the user is up to!

   I guess you're right
4. tooruu commented on Jul 12, 2024

   

   tooruu

   on Jul 12, 2024

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   This isn't high priority, or might not even get addressed. Regardless, it is a bug so I had to bring it to your attention.

   👍React with 👍1Reacted by Ekopalypse