Add marshmallow 4.x support with backward compatibility#326
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gtmanfred merged 11 commits intoplangrid:masterfrom Feb 2, 2026
Merged
Add marshmallow 4.x support with backward compatibility#326gtmanfred merged 11 commits intoplangrid:masterfrom
gtmanfred merged 11 commits intoplangrid:masterfrom
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- Add MARSHMALLOW_VERSION_MAJOR constant for version detection - Add is_schema_ordered() helper to handle removed 'ordered' attribute - Update get_schema_fields() and get_required() to use is_schema_ordered() - Bump marshmallow version constraint from <4 to <5 In marshmallow 4.x, the 'ordered' Meta option was removed because field order is now always preserved (Python 3.7+ dict ordering). The is_schema_ordered() helper abstracts this difference: - 3.x: checks schema.ordered attribute (default False = sort fields) - 4.x: always returns True (fields preserve insertion order)
marshmallow-objects is an archived library incompatible with marshmallow 4.x (passes 'context' to Schema.__init__() which was removed). - Import marshmallow_objects conditionally with try/except - Test instantiation to detect runtime incompatibility - Define MARSHMALLOW_OBJECTS_AVAILABLE flag - Move Model class definitions inside conditional block - Create conditional test case lists for parametrized tests Users on marshmallow 3.x can still use marshmallow-objects.
- Remove 'parametrize' import causing source reading issues - Split test_additional_properties into 4 individual tests - Add skipif for test_self_referential_nested_pre_3_3 (uses removed 'self' nested reference in 4.x) - Compare 'required' field as set since order varies between versions - Add MARSHMALLOW_VERSION constant for version-specific behavior
Error message format for datetime validation changed between versions. Check for 'isoformat' substring rather than exact message match.
Test against: - marshmallow==4.0.0 - marshmallow==4.0.1 - marshmallow>4.0.1 (latest)
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Howdy, thanks for opening this. I will try and get a review in before the end of the week. |
gtmanfred
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Jan 26, 2026
To avoid pip install marshmallow>4 piping the output of `pip install marshmallow` to a file called `4`.
illusional
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Feb 2, 2026
Co-authored-by: Michael Franklin <michael@illusional.net>
…ar into mashmallow_4x_support
illusional
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Feb 2, 2026
gtmanfred
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Summary
This PR adds support for marshmallow 4.x while maintaining backward compatibility with marshmallow 3.x.
Changes
Core Library
Test Fixes
CI
Testing
Breaking Changes in Marshmallow 4.x Addressed