chore(backlog): TASK-59 all ACs checked + Done

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: ahrzb

backlog/tasks/task-59 - Stage-B-join-multiplicity-under-shapemany-—-dup-key-cross-inequality-and-self-joins.md

@@ -3,10 +3,10 @@ id: TASK-59
 title: >-
   Stage B: join multiplicity under shape='many' — dup-key, cross/inequality, and
   self-joins
-status: In Progress
+status: Done
 assignee: []
 created_date: '2026-07-28 01:55'
-updated_date: '2026-07-28 01:57'
+updated_date: '2026-07-28 03:07'
 labels:
   - specializer
   - stage-b
@@ -29,12 +29,12 @@ Hard stop after shipping: columnar-API discussion with the user before any next
 
 ## Acceptance Criteria
 <!-- AC:BEGIN -->
-- [ ] #1 Pins spec for multiplicity semantics (emission order/determinism, LEFT-miss, cross/inequality, self-join star forms, NULL keys among dups) with raw JSONs
-- [ ] #2 All stage-B constructs REJECT under shape='filter'/'map' exactly as today; they build only under shape='many'
-- [ ] #3 1:N equi-joins, cross/inequality joins, and self-joins serve bit-exact (order-insensitive multiset vs DuckDB) under shape='many'
-- [ ] #4 Corpus replay strictly above 529 with zero FAILs (replay builds stage-B cases with shape='many')
-- [ ] #5 Limitations doc + twin updated: stage-B rows move from 'designed, not built' to the shape='many' contract
-- [ ] #6 Full gates green on release build; PR opened (stacked on #44)
+- [x] #1 Pins spec for multiplicity semantics (emission order/determinism, LEFT-miss, cross/inequality, self-join star forms, NULL keys among dups) with raw JSONs
+- [x] #2 All stage-B constructs REJECT under shape='filter'/'map' exactly as today; they build only under shape='many'
+- [x] #3 1:N equi-joins, cross/inequality joins, and self-joins serve bit-exact (order-insensitive multiset vs DuckDB) under shape='many'
+- [x] #4 Corpus replay strictly above 529 with zero FAILs (replay builds stage-B cases with shape='many')
+- [x] #5 Limitations doc + twin updated: stage-B rows move from 'designed, not built' to the shape='many' contract
+- [x] #6 Full gates green on release build; PR opened (stacked on #44)
 <!-- AC:END -->
 
 ## Implementation Plan
@@ -46,3 +46,13 @@ TODAY: both backends are strictly one-emit-per-row. Interpreter: per row, block
 
 DESIGN DIRECTION for multiplicity (validate in spec): (1) emission becomes an explicit operation instead of a terminal side effect — either Inst::EmitRow (appends the current out-lane values) with CTerm::Emit demoted to plain end-of-row, or loop-structured blocks using the EXISTING Brif/Jump machinery (loop header + body + back-edge) with an EmitRow inst in the body. Verify/canonicalize must accept back-edges (check: today's block graph is probably a DAG — verify.rs may assume forward-only; if so that is the first thing to extend). (2) New probe ops: ProbeStart {join} -> cursor, ProbeNext {join, cursor} -> (has: i1, cursor', value lanes) over per-key row LISTS in StaticTy::Map (values become Vec-of-rows per key — flat arena + (off, len) per key is the lean layout). (3) Cranelift: emission via a helper call h_emit_row(cx) that appends to st.out (helpers already write through Cx), loop via normal CLIF blocks — feasible without new architecture; the return code stays for trap/end only. If this turns out heavy, interpreter-first for shape='many' with cranelift fallback is the documented fallback plan (bench guard exempts 'many' from backend-identity tests). (4) Self-join: per-call build of the batch-side map before the row loop (new PreparedStatic variant built in run(), or a batch-map handed via RunState); marshaller unaffected. (5) Cross/inequality: a join with ZERO key columns = single bucket = ProbeStart/Next over the whole static (or batch) + residual predicate in the loop body. (6) LEFT: emit null-extension when the loop body emitted nothing for this row (a per-row 'any_emitted' flag register). (7) shape gate: prepare learns the target shape (prepare_opaque param or Prepared metadata + duckdb/mod.rs check): multiplicity constructs produce a NAMED reject unless shape='many'; corpus replay builds stage-B-shaped cases with shape='many' (detect by retrying on the named errors, or always pass shape='many'? NO — corpus must keep proving the default rejects; retry-with-many on the named needles is the honest harness).
 <!-- SECTION:PLAN:END -->
+
+## Final Summary
+
+<!-- SECTION:FINAL_SUMMARY:BEGIN -->
+Stage B shipped as two stacked PRs: #45 (part 1: dup-key equi-joins, cross/inequality/constant-ON joins) and #46 (part 2: self-joins via the batch as build side). Corpus 529 -> 550 match / 0 FAIL of 678 (81%); the 27-case stage-B pool is fully resolved (21 served + 3 USING-self-join named rejections + 3 rowid self-joins routed to the documented rowid descope).
+
+Everything builds ONLY under shape='many' (TASK-58's fence): default shapes are byte-identical, dup keys and self-joins still reject. Machinery: Term::EmitTo emit-and-continue back-edges (verifier now allows terminating cycles only), StaticTy::MultiMap (stable-sorted equal-key runs; insertion order = the engine's documented 1:N emission order) + ProbeRange/ProbeRead, StaticTy::BatchMap (per-call batch flattening for self-joins, whole ON as per-pair residual — cross-then-filter, pins-proved identical), loop-structured lowering riding state on the live stack with per-block probe-cache reseeds (block splits from CASE machinery), residual-vs-WHERE gate split (residual decides match-ness and the LEFT null-extension; WHERE only gates emission). Interpreter-only; cranelift pre-rejects into the existing fallback.
+
+Central pins finding: DuckDB's join output ORDER is a hash-join accident (LIFO chains, lockstep vector passes, run-to-run divergence at scale) — parity is MULTISET (corpus sorts; duck oracle tests sort), and the engine's own deterministic order (probe outer, insertion inner, null-extension in place) is pinned as a test. Pins: 2026-07-28-stageB-multiplicity-pins.md + pins-stageB/*.json (5 agents, 57 pins). Follow-up left open: USING/NATURAL self-joins (named rejection).
+<!-- SECTION:FINAL_SUMMARY:END -->