Ensure custom __init__() is called when using model_validate_strings()#12897
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Viicos merged 2 commits intopydantic:mainfrom Mar 25, 2026
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davidhewitt
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Mar 9, 2026
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Thanks, implementation seems correct however I would like the test to be unified with existing one please.
Viicos
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__init__() is called when using model_validate_strings()
Merging this PR will improve performance by 5.22%
|
| Benchmark | BASE |
HEAD |
Efficiency | |
|---|---|---|---|---|
| ⚡ | test_complete_core_isinstance |
1.6 ms | 1.5 ms | +5.22% |
| ⚡ | test_complete_core_error |
1.6 ms | 1.5 ms | +5.12% |
Comparing siewcapital:fix-model-validate-strings-custom-init (16dafbf) with main (0574aaa)
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This PR does not seem to contain any modification to coverable code. |
Viicos
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Mar 25, 2026
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Summary
model_validate_strings()currently skips the custom__init__path for models becauseStringMappingalways returnsNonefromInput::as_kwargs().This causes behavior differences compared to
model_validate()/model_validate_json()for models that override__init__, and is the root issue reported in #12718.Changes
StringMapping::as_kwargs()when the input is a mapping.Nonefor non-mapping (String) values.model_validate_strings()invokes a custom__init__and forwards string mapping values.Tests
uv run pytest tests/test_edge_cases.py -k "custom_init or model_validate_strings_custom_init_called or init_inspection"uv run pytest tests/test_main.py -k "model_validate_strings"Closes #12718