Constrain renderers to only stringify items inheriting from BaseTag

[pydanny]

Issue(s)

#547

Description

@bluerosej discovered that Air's Jinja rendering system is stringifying everything. She also provided a fix in pyladiesmanila/VoicesOfPyLadiesManila#18. We expand on that excellent fix by constraining it to just stringify BaseTag-inherited items so that Jinja can operate normally.

Pull request type

Please check the type of change your PR introduces:

• Bugfix
• New feature
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe):

Pull request tasks

The following have been completed for this task:

• Code changes
• Documentation changes for new or changed features
• Alterations of behavior come with a working implementation in the examples folder
• Tests on new or altered behaviors

Checklist

• I have run just test and just qa, ensuring my code changes passes all existing tests
• I have performed a self-review of my own code
• I have ensured that there are tests to cover my changes

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Codecov Report

✅ All modified and coverable lines are covered by tests.

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[Copilot]

Pull Request Overview

This PR fixes a bug where Air's Jinja rendering system was stringifying all variables in the template context, preventing normal Jinja operations on non-tag objects like lists and dictionaries. The fix constrains stringification to only objects that inherit from BaseTag, allowing Jinja to process other data types normally.

• Modified context processing to only stringify BaseTag instances
• Added test coverage for Jinja's handling of lists and dictionaries
• Created supporting test template to verify proper rendering behavior

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
src/air/templating.py	Updated context processing logic to conditionally stringify only BaseTag instances
tests/test_templating.py	Added test to verify Jinja can process lists and dicts without stringification
tests/templates/lists_and_dicts.html	Created test template that renders metadata and iterates over list items

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[intellectronica]

LGTM

---

One other option that could make this a bit more readable (subjectively, to my eyes) would be:

def _jinja_context_item(self, item):
    """Prepare an item for processing by Jinja
    
    BaseTag instances are converted to string.
    All other objects are handled by Jinja directly.
    """

    if isinstance(item, BaseTag):
        return str(item)
    return item

...

context = {k: self._jinja_context_item(v) for k, v in context.items()}

It's a matter of taste and I wouldn't block on merging - the change looks perfect - but this more verbose version is self-documenting and easier to extend if the need ever arises.

[alaminopu]

Type of the __call__ function should be updated accordingly to _TemplateResponse or str | _TemplateResponse

[pydanny]

This suggested change throws all kinds of type errors. For now I'm merging this in, will look at the typing issue in a separate PR.

[pydanny]

@intellectronica I made the change you suggested and gave you attribution. Thanks!