Could you give a simple example, demonstrating exactly what gets rendered incorrectly, and how this fix affects it?

Could you give a simple example, demonstrating exactly what gets rendered incorrectly, and how this fix affects it?

Of course. I have made the following#3464 (comment)

Okay. That's something, tho a minimal code example would still be helpful.

I agree, I'd love to see a basic example of how this occurs.

Ok, here is code that reproduces exactly the error that this pull request fixes:

fromrest_frameworkimportserializersfromrest_framework.renderersimportHTMLFormRendererclassLevel2NestedSerializer(serializers.Serializer):some_field=serializers.CharField()classLevel1NestedSerializer(serializers.Serializer):nested2_field=Level2NestedSerializer(allow_null=True)another_field=serializers.CharField()classLevel0NestedSerializer(serializers.Serializer):nested1_field=Level1NestedSerializer()serializer=Level0NestedSerializer(data={'nested1_field': {'nested2_field':None,'another_field':'test'    }})serializer.is_valid()renderer=HTMLFormRenderer()forfieldinserializer:rendered=renderer.render_field(field, {})

Okay, and how does the HTML form render before/after the fix. (Include screenshots if you're feeling generous! 😎 )

Okay, and how does the HTML form render before/after the fix. (Include screenshots if you're feeling generous! )

Before the fix, it does not render at all. It crashes with a traceback.
After the fix, it renders ok. For the nested field withNone value, an empty form is rendered.

Would you consider pulling together a test case? Failing that wemight consider merging in any case and adding that as an outstanding issue.

Would you consider pulling together a test case?

Sure. Added in this pull request.

Good stuff, thanks!