Django Template System Enhancement Proposal

Your proposal to allow newlines within {% %} tags in Django templates addresses a legitimate usability concern. Based on the Django template system's design philosophies, this change aligns with several principles:

1. Discourage redundancy - Allowing newlines would make complex template tags more readable
2. Assume designer competence - This would provide template authors with more flexibility
3. Treat whitespace obviously - Currently, whitespace handling within tags is not intuitive

Technical Implementation

Your suggested approach of modifying the regular expression to include the re.DOTALL flag is a reasonable starting point:

PYTHONCopied
tag_re = re.compile(r"({%.*?%}|{{.*?}}|{#.*?#})", re.DOTALL)

Backward Compatibility Considerations

You correctly identified the backward compatibility issue. Currently, a template with:

{% 
%}

renders as a literal string, but with your change, it would trigger a parsing error.

Potential Solutions

Your suggestion to provide an option in template settings with a deprecation warning is a good approach that follows Django's typical pattern for introducing potentially breaking changes. This could be implemented as:

1. Add a new setting to DjangoTemplates backend and Engine class
2. Default to the current behavior for existing projects
3. Set the new behavior as default for new projects via startproject
4. Include appropriate deprecation warnings

This approach would allow for a smooth transition while giving developers time to update their templates if needed.

Additional Considerations

• Documentation would need to be updated to reflect this change
• Test coverage would be essential to ensure all edge cases are handled
• The error messages for malformed tags should be improved to be more descriptive, especially for beginners

This enhancement would improve the developer experience while maintaining the core principles of Django's template system.