Module derived_cache 

Content-addressed derived-index cache (ADR-099/ADR-112) — port of services/derived_cache.py DerivedIndexCache.load_or_build plus the stat-manifest freshness rungs of services/freshness.py the one-shot path consumes (INDEX-PLAN B3).

Every failure mode degrades to a fresh build: enabling the cache can only change latency, never an answer or an exit code (ADR-080).

Structs

DerivedIndexCache

Enums

ReadModel

What load_or_build returns: a memory-mapped store view (the warm path), or the freshly built structures when the store could not be written or reopened (ADR-080 — never a failure).

Constants

CACHE_DIR_ENV

Functions

cache_enabled

Whether the persistent cache is active for this invocation (ADR-112): on by default; --no-cache per invocation, non-empty DECIDED_NO_CACHE environment-wide.

corpus_hash_from_complete_manifest

Recompose the corpus hash from a complete scan-order manifest without a second filesystem walk. stat_scan always returns exactly this shape.

corpus_hash_from_manifest

Reproduce corpus_content_hash from the manifest’s cached hashes.

default_cache_dir

The derived-cache directory ladder: DECIDED_CACHE_DIR > $XDG_CACHE_HOME/decisions/derived > ~/.cache/decisions/derived > <tmp>/decided-cache/decisions/derived (the homeless floor — never raises).

stat_scan

Diff the corpus against prev_manifest by stat, content-confirming changes. Returns the rebuilt manifest (scan order) and the changed set.

write_marker_public

The tracker’s compaction gate (INDEX-PLAN B6): write the marker for an already-landed store.