Previously all three streams reconfigured to UTF-8 with errors='strict'.
That kills 'mempalace search' the moment a drawer carrying a surrogate
half (round-tripped from a filename via surrogateescape) hits print(),
losing the rest of the result block. Same hazard for warning lines on
stderr.
Split the policy:
stdin -> surrogateescape (malformed bytes from a redirected file
survive as lone surrogates instead of crashing the read)
stdout -> replace (drawer text with a stray surrogate becomes U+FFFD
instead of UnicodeEncodeError mid-print)
stderr -> replace (same protection for logger / warning paths)
Applied identically in the cli.py and fact_checker.py helpers; the DRY
extraction into a shared module is a separate cleanup ask, kept out of
this fix to keep the diff narrow.
Tests updated for the new per-stream assertion.
The `python -m mempalace.fact_checker --stdin` entry point reads non-ASCII
text through the system ANSI codepage (cp1252/cp1251/cp950) on Windows,
which mojibakes characters before claim-extraction sees them. Reconfigure
stdin/stdout/stderr to UTF-8 with `errors="strict"`, wrapped in try/except
so a replaced stream (Jupyter, test harness) logs a warning rather than
crashing the CLI.
Mirrors the same fix shipped for `mcp_server.py:main()` (#400) and
`hooks_cli.py:run_hook()` (#1280) -- this is the third and last
stdin-reading entry point in the package.
Merges the full hardened stack (up through #791 drawer-grep) and turns
fact_checker from "dead code hidden behind bare except" into an
actually-working offline contradiction detector with tests.
## Dead paths the PR body advertised but the code never executed
Both buried by a single outer ``except Exception: pass``:
* ``kg.query(subject)`` — ``KnowledgeGraph`` has no ``query()`` method;
it has ``query_entity()``. The attribute error was silently swallowed
and the entire KG branch always returned ``[]``. Now using
``kg.query_entity(subject, direction="outgoing")`` with proper
handling of the ``predicate``/``object``/``current``/``valid_to``
fields the real API returns.
* ``KnowledgeGraph(palace_path=palace_path)`` — the constructor's only
kwarg is ``db_path``. Passing ``palace_path`` raised TypeError,
silently swallowed. Now computing the db_path correctly from
``<palace>/knowledge_graph.sqlite3``, matching the convention the
MCP server already uses.
## Contradiction logic rewritten
The previous ``if kg_pred in claim and fact.object not in claim`` only
fired when text used the SAME predicate word as the KG fact — the exact
opposite of the stated use case ("Bob is Alice's brother" when KG says
husband" would NOT have fired). Replaced with a proper parse → lookup
→ compare pipeline:
* ``_extract_claims`` parses two surface forms ("X is Y's Z" and
"X's Z is Y") into ``(subject, predicate, object)`` triples.
* ``_check_kg_contradictions`` pulls the subject's outgoing facts
and flags two classes:
- ``relationship_mismatch`` when a current KG fact matches the
same ``(subject, object)`` pair but with a different predicate.
- ``stale_fact`` when the exact triple exists but is
``valid_to``-closed in the past.
* Stale-fact detection is now implemented (the PR body claimed it;
the old code silently didn't implement it).
## Performance fix — O(n²) → O(mentioned × n)
``_check_entity_confusion`` previously computed Levenshtein for every
pair of registered names on every ``check_text`` call. For 1,000
registered names that's ~500K edit-distance calls per hook invocation.
Now we first identify which registry names actually appear in the text
(single regex scan), then only compute edit distance between mentioned
and unmentioned names. Pinned by a test that asserts <200ms on a 500-
name registry with zero mentions.
Also: when *both* similar names are mentioned in the text, we no
longer flag them — the user clearly knows they're different people.
## Shared entity-registry loader
``mempalace/miner.py`` already had an mtime-cached loader for
``~/.mempalace/known_entities.json``. fact_checker had a duplicate
implementation that leaked file handles and ignored caching. Extended
miner's cache to expose both the flat set (``_load_known_entities``)
and the raw category dict (``_load_known_entities_raw``); fact_checker
now imports the latter. No more double disk reads, no more handle leak.
## Tests — 24 cases in tests/test_fact_checker.py
All three detection paths + both dead-code regressions:
* ``test_kg_init_uses_db_path_not_palace_path_kwarg`` — pins the
correct KG constructor signature so the ``palace_path=`` bug can't
come back.
* ``test_relationship_mismatch_detected`` — the headline example from
the PR body now actually fires.
* ``test_stale_fact_detected`` — valid_to-closed triple is flagged.
* ``test_current_fact_same_triple_is_not_flagged`` — no false positive
on a still-valid match.
* ``test_performance_bounded_by_mentioned_names`` — 500-name registry,
zero mentions, <200ms. Regression for the O(n²) blowup.
* ``test_no_false_positive_when_both_names_mentioned`` — Mila and
Milla in the same text is fine.
* Plus claim extraction, flatten_names shapes, CLI exit code, empty
text handling, missing-palace graceful fallback, registry-dict
shape support.
785/785 suite pass. ruff + format clean on CI-pinned 0.4.x.
mvalentsev