Potential infinite loop in src/sage/categories/coercion_methods.pyx

[jdemeyer]

This code from src/sage/categories/coercion_methods.pyx looks like a potential infinite loop:

    if have_same_parent_c(self, right) and hasattr(self, "_add_"):
        return self._add_(right)
    return coercion_model.bin_op(self, right, operator.add)

The hasattr(self, "_add_") clause is bad: if there is no _add_, the coercion model will just call __add__, which calls the coercion model, which calls __add__...

Solution: remove the hasattr(self, "_add_").

Hopefully the whole module coercion_methods.pyx can be removed in #20767 and then the problem will disappear by itself.

CC: @nthiery

Component: categories

Reviewer: Jeroen Demeyer

Issue created by migration from https://trac.sagemath.org/ticket/20851

[jdemeyer]

comment:1

Fixed by #20767.

[jdemeyer]

Reviewer: Jeroen Demeyer

[embray]

comment:3

Determined to be invalid/duplicate/wontfix (closing as "wontfix" as a catch-all resolution).