fix: reject non-finite numeric metadata supplied as strings

[Mubashirrrr]

Bug

typed_metadata._coerce_number is used by normalize_metadata / merge_metadata to coerce user-supplied document metadata according to a declared type. For numeric inputs it explicitly rejects NaN/infinite values:

if isinstance(value, (int, float)) and not isinstance(value, bool):
    if isinstance(value, float) and (math.isnan(value) or math.isinf(value)):
        raise TypedMetadataError(f"Metadata field '{field}' cannot store NaN or infinite values.")
    return value

…because those values break JSON serialization (json.dumps(float('inf')) emits Infinity, which is invalid JSON) and Postgres double precision storage. But the string branch did not apply the same guard:

return float(text)

So when a field is declared as number (or an alias like int/float) and the value arrives as a string, "inf", "-inf", "Infinity", "nan", and overflowing literals such as "1e400" (Python parses this to inf) were coerced into non-finite floats and stored, corrupting the document row at write time. Metadata and type hints both come straight from the ingestion request body (see core/services/v2_document_service.py and core/services/ingestion_service.py), so this is reachable from a normal API call.

Reproduction

from core.utils.typed_metadata import normalize_metadata
bundle = normalize_metadata({"score": "inf"}, {"score": "number"})
print(bundle.values["score"])   # inf  -> later breaks json.dumps / Postgres insert

Fix

Apply the existing finite-value check to the parsed string result, raising the same TypedMetadataError the numeric path uses. Four lines added, one changed; valid numeric strings (including scientific notation like "1e5") are unaffected.

Regression test

Extended test_number_coercion_rejects_nan_and_infinity with a string-input case (test_number_coercion_rejects_nan_and_infinity_strings) covering inf, -inf, Infinity, nan, and 1e400. It fails before the fix (DID NOT RAISE) and passes after. Full test_typed_metadata.py suite stays green (47 passed).

$ pytest core/tests/unit/test_typed_metadata.py -q
47 passed

🤖 Generated with Claude Code

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