offline Catholic daily readings and liturgical calendar in Go, with CLI, TUI and web clients https://git.labunix.xyz/lectio.git/atom?h=main 2026-08-24T20:02:39Z 2026-08-24T20:02:39Z Lukasz Kasprzak lukas@labunix.xyz 2026-08-24T20:02:39Z urn:sha1:b24702cc9b8d7f2e408bb92032e8f7fa2aaa836b The prior commit (ea6e598) memoised efTransferPlan but left the SAME occupiedByClass1/Or2 O(len(merged)) scan pattern in a second place: transferIfImpededEF's own fallback path, called from computeEF once per day for every class-1 candidate the (now cached) plan does not resolve -- confirmed by CPU profile, not assumed: computeEF.func1 (the old occupiedByRank closure) was ~62% of BenchmarkDays7EF's total time, almost all of it inside buildCelebration, called from BOTH efTransferPlan internally AND this second, uncached site. Before optimising, established precisely what "occupied" depends on, per the coordinator's warning that occupancy might genuinely mutate during planning (efTransferPlan's own `claimed` map suggested as much). It does not: occupiedByRank asks only "does some OTHER entry's ORIGINAL, untransferred date (buildCelebration + celebrationDate, which never considers a transfer) equal d" -- a pure function of (merged content, year, sel) alone, identical to what the transfer-plan cache already keys on. `claimed`, by contrast, genuinely mutates during one planning pass (it tracks which TARGET days a transfer walk has already assigned) and is NOT part of occupiedByRank's computation at all -- it remains computed fresh inside efTransferPlan every call, untouched by this change. These are independent, not the same thing wearing two names: efTransferPlan's own forward-walk loop already checks both, plus a third condition (the target day's own temporal class), as separate disjuncts. Given that, an occupancy INDEX -- not a second cache, and not a "we already know the answer" shortcut derived from plan's absence (which would have been correct for the transferIfImpededEF fallback's own control flow ONLY by coincidence: it ignores the unconditional All Souls Sunday-transfer special case that runs before the class-1 check on ANY rank, so a shortcut skipping straight past it would misfire the moment a user overlay retagged All Souls class-1, however unlikely on shipped data) -- is the safe fix: buildEFOccupancyIndex does the same merged-scan ONCE, into date -> []{slug, rank}, and .occupied does the exact O(1)-ish lookup + tiny-list filter occupiedByRank always computed, just precomputed. transferIfImpededEF's own signature, control flow and All Souls handling are completely unchanged; only what its two closure parameters read from changed. The index shares the transfer-plan cache's existing key (year, Selection, SHA-256 of merged) rather than adding a new one -- both are pure in exactly those three inputs, built in the same pass, so one key correctly covers both. Only the plan is copied per call (clonePlan); the index, which can hold one entry per merged slug (~330 on shipped data), is returned uncopied and documented immutable-after-construction -- safe under Go's concurrent-read guarantee since nothing anywhere writes to a returned index. New TestEFOccupancyIndexDetectsSameDateClass1Collision covers a path no existing test reached: two class-1 SANCTORAL entries sharing one ORIGINAL date (St Joseph/the Annunciation, covered by the prior commit's tests, collide via HOLY WEEK's temporal precedence on DIFFERENT dates, never with each other). A synthetic overlay (Compute's own public API, same style as the existing tests) puts two class-1 entries on the same otherwise-ordinary date: alone, either is simply observed; both together, RG 97/98 transfer both forward and the shared date reverts to its temporal office. Mutation-proved: dropping the index's exceptSlug self-exclusion (reverted after) made the test fail immediately -- every class-1 entry saw itself in the index and wrongly self-impeded, even the single-entry case. TestEFTransferPlanCacheConcurrentUse gained a third, disjoint key exercising this same collision path from goroutines alongside the two existing ones; `go test -race` on the whole package is clean. Benchmarked (interleaved before/after, same method throughout this branch): BenchmarkDays7EF drops from ~46-48ms (the prior commit's own plan-cache-only state) to ~15-18ms/op (allocs 208639 -> 98727, -53%; bytes 16.1MB -> 4.2MB, -74%) -- roughly a further 3x, ~4.6x cumulative against the original ~74ms. BenchmarkDaysWeek (OF, which never touches any of this) is unaffected: ~4.9-5.9ms/op both before and after, with byte-for-byte identical allocs/bytes in every run -- the ms-level wobble is machine noise, not a regression. A fresh CPU profile confirms the new remaining bottleneck precisely: writeSortedFields/hashMergedForPlan (the cache key's own SHA-256 of merged, ~330 entries) is now ~35% of total time, because it still runs on EVERY day (7x/week) to know whether a call is a cache hit, even though the work it gates now mostly isn't. Not fixed here: hoisting the key computation itself up to mobile.Days's batch level (mirroring the first commit on this branch, b6ee8f0) would need Compute's public signature to accept a precomputed key, a bigger surface change than this task's scope, reported rather than taken unilaterally. Output identity re-verified: the same 492-case sweep (both forms, both UI languages, all four corpora, the leap day/Triduum/Requiem/season- boundary dates, and the three Joseph/Annunciation years) is byte-identical (SHA-256-equal) before and after -- the same SHA-256 as the prior commit's own sweep, confirming zero output drift across the whole chain. go test ./... and make ci (both build tags, oracle/differential suite included) are green; go test -race on the whole internal/calendar package is clean. 2026-08-24T19:42:48Z Lukasz Kasprzak lukas@labunix.xyz 2026-08-24T19:42:48Z urn:sha1:ea6e59862dbdb607b9bcb221212a85ee3e4bd84a computeEF calls efTransferPlan once per day, but the plan is pure in (year, the merged sanctoral content, Selection) and identical for every day sharing those three -- e.g. every date in one mobile.Days week. Rebuilding it per day was a real cost: efTransferPlan walks every merged entry looking for class-1 candidates, and for each one it considers, occupiedByClass1/Or2 (an occurrence check it also uses) walks merged AGAIN -- confirmed by CPU profile, not just by reading the code (github.com/lukaszkasprzak/lectio/internal/calendar.computeEF.func1, the occupiedByRank closure, at ~62% of BenchmarkDays7EF's total time before this fix, almost all of it inside buildCelebration). efTransferPlanCached (transfer_plan_cache.go) wraps efTransferPlan with a small, bounded, thread-safe LRU (container/list + sync.Mutex, capped at 64 entries -- gomobile may call in from multiple goroutines, and an unbounded map keyed by year would grow as a user scrolls through decades). The cache key is (year, Selection, a SHA-256 of merged's full content): merged is a map, so it cannot be a map key field itself, and Go's randomised map iteration order means two calls with identical content can visit it differently, so the hash sorts slugs and, within each entry, its Fields/Variant keys before hashing, and covers every field of every entry -- not just Rank/Date, the ones efTransferPlan's own read path happens to touch today, because which entries even qualify as class-1 is itself computed from that data, and occupiedByClass1/Or2 scan ALL of merged, not just the class-1 subset. Selection is included even though EF date resolution ignores it today (resolveDate never reads its sel parameter) -- keying on it costs nothing (four small strings) and protects a future change from silently poisoning a cache that never accounted for it. The returned map is always a fresh copy (clonePlan), never the cached instance, so sharing it across goroutines needs no further synchronisation. Verified the key is complete rather than trusted: with the content hash temporarily dropped from the key (mutation test, not committed), TestEFTransferPlanCacheInvalidatesOnOverlay failed immediately -- a plan warmed for the shipped 2008 calendar was wrongly served back for the same year with a user overlay applied (the Annunciation suppressed, which changes where the RG 96(a)/97/98 collision sends St Joseph: 31 March instead of 1 April, empirically confirmed against the pre-cache code before the test was written). TestEFTransferPlanCacheInvalidatesOnYear is a lighter companion covering the year field. TestEFTransferPlanCacheConcurrentUse hammers the cache from 12 goroutines across two different keys and reasserts correctness afterward; clean under `go test -race`. Benchmarked (interleaved before/after, same method as the readings.Prepare commit, to control for machine thermal drift): BenchmarkDays7EF drops from ~48-51ms to ~32-35ms/op (allocs 253810 -> 208639, -18%; bytes 28.1MB -> 16.1MB, -43%), roughly a third faster. BenchmarkDaysWeek (OF, which never calls efTransferPlan at all) is unaffected, ~3.5-4.1ms/op both before and after -- within noise, confirming this change is EF-only as intended. EF remains well outside OF's range (~32ms vs ~4ms), and a fresh CPU profile after this fix places the dominant remaining cost precisely: it is the SAME occupiedByClass1/Or2 pattern, but living OUTSIDE efTransferPlan -- transferIfImpededEF's own fallback path, called once per day for every class-1 candidate NOT already resolved by the (now cached) plan, i.e. the ordinarily-unimpeded ones (~15-20 of them), each triggering another O(len(merged)) scan. That call site was not part of what this task named, and memoising it is a materially different change (it is keyed per-candidate, not once per day), so it is reported here rather than folded into this commit. Output identity re-verified: a 492-case sweep of mobile.Day/mobile.Days (both forms, both UI languages, all four corpora, a leap day, the Sacred Triduum, a Requiem day, Christmas/Pentecost/Assumption/All Souls windows, and the three Joseph/Annunciation transfer-collision years this fix specifically touches -- 2008, 2035, 2046) produced byte-identical (SHA-256-equal) JSON before and after. go test ./... and make ci (both build tags, oracle/differential suite included) are green.