Refactor very similar code of internal dec function for simple_tag, simple_block_tag and inclusion_tag

[Emma Delescolle]

The internal dec function used by simple_tag, simple_block_tag and inclusion_tag are very similar. There are also similarities in the process of determining the return value of these methods (the decorated function or the decorator itself). These similarities should be refactored.

• ​https://github.com/django/django/blob/main/django/template/library.py#L111
• ​https://github.com/django/django/blob/main/django/template/library.py#L165
• ​https://github.com/django/django/blob/main/django/template/library.py#L250

Refactoring this function to be either a method of the Library class they are defined in or as a completely separate function would:

• reduce the amount of code to maintain
• render change easier if anything ever has to change inside those
• allow the end-user to use that function/method to create their own complex template tags

[David Sanders]

Hi & thanks for your interest in helping out with Django.

The Django codebase usually tends to follow the WET (Write Everything Twice/Thrice) and in the case you've highlighted there doesn't appear to be a major advantage in modifying code to risk reducing readability and/or introduce regressions.

Will close the ticket for now but if you disagree feel free to head over to the Django Forum to start a discussion 👍