BM25Scorer.score_batch() ranks a real corpus of documents but weighted
every matched term with a constant idf=log(2.0), so a ubiquitous noise
word counted the same as a discriminative UUID. The _compute_idf() helper
needed to do this properly already existed (and was unit-tested) but was
never wired into scoring.
- Implement _compute_idf() with the standard floored BM25 IDF its docstring
documents: log((N - n + 0.5) / (n + 0.5) + 1).
- Thread an optional per-term idf_map through _bm25_score(); single-document
score() keeps the neutral log(2.0) weight (no corpus to estimate from).
- score_batch() now computes document frequency across the batch and builds
the IDF map, so rare/discriminative terms outrank corpus-wide terms in the
ranking that CompressionStore.search() and HybridScorer consume.
Adds tests covering the IDF formula and the batch ranking behaviour.
Stage 3c.1b step 2 + cleanup. The python `SmartCrusher` (3669 lines)
is replaced by a thin pyo3-backed shim (~290 lines) that delegates
every byte to `headroom._core.SmartCrusher` (built from
`crates/headroom-py`, landed in the previous commit). There is no
python implementation and no env-var fallback — the wheel is a hard
import.
Why now: parity was already proven across 17 fixtures + the python-
side bridge test (1+17 in `test_smart_crusher_rust_parity.py`).
Keeping a shadow python impl behind a flag is a permanent maintenance
cost with no operational benefit. Stage 3c.1b deletes ~3380 lines of
python parser/scorer/analyzer/orchestrator code; the rust crate has
its own coverage (388 unit tests + property tests in headroom-core).
Surface preserved (drop-in for every production caller):
- `headroom.transforms.smart_crusher.SmartCrusher` — same class name,
same `__init__(config, relevance_config, scorer, ccr_config)`
signature (the latter three are accepted for source-compat and
silently dropped — rust port keeps those subsystems disabled in
Stage 3c.1, they re-attach in Stage 3c.2).
- `SmartCrusherConfig` and `CrushResult` dataclasses kept as python
dataclasses (callers use `asdict()` / dataclass matching on them).
- `crush(content, query, bias)`, `_smart_crush_content(content, ...)`,
`apply(messages, tokenizer, **kwargs)`, and
`_extract_context_from_messages(messages)` all preserved.
- `smart_crush_tool_output(content, config, ccr_config)` thin wrapper.
The transform-protocol `apply()` orchestration stays python (message
walking, digest-marker insertion, token counting); only the per-
message compression call delegates to rust.
Removed:
- Python parser / planner / scorer / analyzer / classifier (~3380 lines).
- Internal helpers `_classify_array`, `_detect_sequential_pattern`,
`_detect_rare_status_values`, `_detect_items_by_learned_semantics`,
`_percentile_linear`, `_compute_k_split`, `_crush_number_array`,
`_process_value`, etc. — rust crate has parallel coverage.
- `SmartAnalyzer`, `ArrayType`, `CompressionStrategy`,
`extract_query_anchors` — internals; not used by any production
caller (only tests probed them).
Tests deleted (probed deleted internals — same precedent as Stage 3b):
- `tests/test_transforms/test_smart_crusher.py` (40 tests)
- `tests/test_transforms/test_universal_json_crush.py` (45)
- `tests/test_transforms/test_anchor_selector.py` (49)
- `tests/test_toin_field_learning.py` (21)
- `tests/test_crushability.py` (20)
Tests trimmed (removed methods/classes that probe deferred subsystems
— scorer injection, CCR marker injection, TOIN feedback recording —
all of which re-attach in Stage 3c.2):
- `tests/test_transforms/test_smart_crusher_bugs.py`:
TestNumberArraySchemaPreservation, TestStage3c1BugFixes.
- `tests/test_relevance.py`: 2 scorer-injection tests.
- `tests/test_ccr.py`: TestSmartCrusherCCRIntegration class +
test_custom_marker_template.
- `tests/test_toin_integration.py`: TestTOINIntegration +
TestStoreToTOINHash classes.
- `tests/test_critical_fixes.py`: TestSmartCrusherTOINIntegration +
test_full_feedback_loop.
- `tests/test_acceptance.py::TestQueryAnchorExtraction`: dropped the
`extract_query_anchors` probe; kept the end-to-end "Alice
preserved" assertion.
Bug fixes from Stage 3c.1 (#1 percentile linear interp, #2 zero-
padded sequential, #3 rare-status pareto, #4 k-split overshoot) are
pinned by the rust crate and the parity fixtures
(`tests/parity/fixtures/smart_crusher/`).
Tests:
- 517 passed in the smart_crusher-adjacent file set
(test_transforms/, test_relevance*, test_ccr, test_toin_integration,
test_quality_retention, test_acceptance, test_critical_fixes).
- 18 in `test_smart_crusher_rust_parity.py` (1 sanity + 17 fixtures).
- 388 rust unit tests still green.
One stale-error-message regex in `test_relevance_extra.py` updated
from "requires sentence-transformers" → "requires fastembed".
- Fix 34 mypy errors across 17 files with type annotations and casts
- Add type: ignore comments for legitimate dynamic patterns
- Handle None operands with (value or 0) pattern
- Cast return values to proper types (int, float, str, bool)
- Add EstimatingTokenCounter imports where needed
- Use getattr() for potentially missing attributes
- Fix flaky test_paraphrase_match with more distinct semantic examples
- Add mlx to mypy ignore list (broken third-party stubs)
