[yuxino]

ItemAdapter.get_json_schema() raises AttributeError when a typed mapping field uses json_schema_extra with additionalProperties: False, such as a quantity mapping that only allows named sizes. Boolean items overrides on typed sequences fail for the same reason.

Preserve explicit boolean schemas instead of trying to infer types into them. Dictionary-valued schemas and fields without overrides retain their existing type inference.

The five regression cases fail on the original implementation and pass with this fix. The test suite (excluding optional CodSpeed benchmarks), README examples, type/lint checks, and package checks pass on Python 3.14. Independent checks also verified the generated schemas and their validation behavior across dataclass, TypedDict, attrs, Pydantic and Scrapy items.

AI assistance: this change was prepared and checked with OpenAI Codex.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.88%. Comparing base (9bab3af) to head (8c8f352).
⚠️ Report is 2 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #153   +/-   ##
=======================================
  Coverage   99.88%   99.88%           
=======================================
  Files           6        6           
  Lines         842      844    +2     
  Branches      160      161    +1     
=======================================
+ Hits          841      843    +2     
  Partials        1        1           

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[codspeed]

Merging this PR will not alter performance

✅ 24 untouched benchmarks
⏩ 4 skipped benchmarks¹

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_{Comparing febug:fix/boolean-schema-overrides (8c8f352) with master (9bab3af)}

Footnotes

1. 4 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩