fix(upload): correct on_drop_rejected args spec

[BABTUNA]

All Submissions:

• Have you followed the guidelines stated in [CONTRIBUTING.md](https://
  github.com/reflex-dev/reflex/blob/main/CONTRIBUTING.md) file?
• Have you checked to ensure there aren't any other open Pull
  Requests for the desired
  changed?

Type of change

• Bug fix (non-breaking change which fixes an issue)

New Feature Submission:

• Does your submission pass the tests?
• Have you linted your code locally prior to submission?

Changes To Core Features:

• Have you added an explanation of what your changes do and why you'd
  like us to include them?
• Have you written new tests for your core changes, as applicable?
• Have you successfully ran tests with your changes locally?

Description

This fixes the Upload.on_drop_rejected trigger args spec.

Before this change, on_drop_rejected used the same spec as on_drop
(list[rx.UploadFile]), which is incorrect for rejected files.
Now on_drop_rejected uses its own spec (list[dict[str, Any]]) and is
wired on both GhostUpload and Upload.

Changes included:

• Added _on_drop_rejected_spec = passthrough_event_spec(list[dict[str, Any]]).
• Updated on_drop_rejected type annotations in GhostUpload and
  Upload.
• Added regression test:
  • test_on_drop_rejected_uses_file_rejection_payload_spec
• Updated pyi_hashes.json for packages/reflex-components-core/src/ reflex_components_core/core/upload.pyi.

Validation

• uv run pytest tests/units/components/core/test_upload.py -q
• uv run ruff check packages/reflex-components-core/src/ reflex_components_core/core/upload.py tests/units/components/core/ test_upload.py

Closes #6205

[greptile-apps]

Greptile Summary

This PR fixes a bug where on_drop_rejected on both GhostUpload and Upload was incorrectly typed with _on_drop_spec (list[UploadFile]) instead of the correct list[dict[str, Any]] that react-dropzone's FileRejection[] payload actually delivers. The fix introduces a dedicated _on_drop_rejected_spec constant and wires it consistently in both components, aligning with the shape already expected by the existing _default_drop_rejected helper.

Confidence Score: 5/5

Safe to merge — targeted one-line spec fix with a regression test and updated pyi hash.

All findings are P2 (minor test coverage gap). The fix is correct, well-scoped, and consistent with the existing _default_drop_rejected implementation that already used list[dict[str, Any]].

No files require special attention.

Important Files Changed

Filename	Overview
packages/reflex-components-core/src/reflex_components_core/core/upload.py	Introduces _on_drop_rejected_spec using list[dict[str, Any]] and wires it to GhostUpload.on_drop_rejected and Upload.on_drop_rejected, correctly replacing the previously incorrect _on_drop_spec (list[UploadFile]). The new spec aligns with the react-dropzone FileRejection[] payload shape already expected by _default_drop_rejected.
tests/units/components/core/test_upload.py	Adds regression test test_on_drop_rejected_uses_file_rejection_payload_spec that verifies Upload.on_drop_rejected now carries the correct list[dict[str, Any]] placeholder type. GhostUpload is not tested separately (minor gap).
pyi_hashes.json	Hash for upload.pyi updated to reflect the changed event handler type signature — consistent with the source change.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[react-dropzone onDropRejected callback] -->|FileRejection array| B[on_drop_rejected trigger]
    B --> C{Component}
    C -->|GhostUpload| D["_on_drop_rejected_spec: list of dict"]
    C -->|Upload| D
    D --> E[User event handler receives list of FileRejection dicts]

Loading

_{Reviews (1): Last reviewed commit: "Fix upload on_drop_rejected args spec" | Re-trigger Greptile}

[greptile-apps]

Test only covers Upload, not GhostUpload

The new test validates the spec for Upload.on_drop_rejected, but GhostUpload.on_drop_rejected was also changed in this PR. Since both are wired to the same _on_drop_rejected_spec constant, the fix is correct for both, but the test coverage doesn't verify GhostUpload's trigger independently. Consider adding a parallel assertion for GhostUpload.get_event_triggers()["on_drop_rejected"] to ensure it stays in sync if the specs ever diverge.