* fix(deriver): strip NUL bytes from model-generated observations
Postgres rejects NUL (0x00) in text columns and in jsonb strings. API
ingress has always stripped it from user-supplied content, but the
deriver's own output did not go through any equivalent: a model can emit
a \u0000 escape in its tool-call arguments, which the JSON parser decodes
into a real NUL byte. Seen in production when models transcribe shell
output (`tr '\x00' '\n'`) or Windows paths (`c:\<NUL>users\amal`).
The NUL reached the exact-content dedup pre-fetch in create_documents as
a bind parameter, so the query raised DataError before any row was
written and the whole batch for that observer was dropped.
Strip in _normalized_observation and _normalized_observation_input --
the points that already normalize text for persistence and embedding --
so the embedded text matches the stored text. premises and sources are
covered too, since they ride along in internal_metadata. The emptiness
check now runs after normalization, because str.strip() does not remove
NUL and all-NUL content would otherwise be stored as an empty string.
DocumentCreate.content gets a mode="before" validator as a backstop for
callers that bypass those paths; running before the length constraint
makes all-NUL content fail min_length rather than silently empty out.
The NUL helpers move out of schemas/api.py into utils/sanitization.py as
a single recursive strip_nul, so ingress and internal paths share one
implementation. It is overloaded to keep str -> str for the callers that
chain .strip(), and passes None through so optional fields need no guard.
Fixes HONCHO-4XZ
* fix: broaden nul strip check
* chore: code simplification
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Co-authored-by: Vineeth Voruganti <13438633+VVoruganti@users.noreply.github.com>
Eugene Eisenstein