# Implementation Plan: job-array-single-wal-record - [ ] 1. Foundation: WAL/schema additions and jobj.c hardening - [x] 1.1 (P) Add the array WAL record type - Add a new `WAL_JOB_ARRAY_SUBMIT` value to the WAL entry type set, distinct from `WAL_JOB_SUBMIT` - Classify it as a WAIT-mode (requester-awaiting) commit, same as the existing single-job type - Observable: the new type is recognized by the WAL commit-mode classifier and compiles cleanly; the existing single-job type's classification is unchanged - _Requirements: 1.1, 1.2, 1.3_ - _Boundary: WAL Array Submission_ - [x] 1.2 (P) Add the compact array push wire variant - Add one new additive variant to the existing controller-to-scheduler/apiserver push message, reusing the client submit request's existing (base jobid, array size, one spec) shape verbatim — no new struct - Observable: the schema compiles and generates encode/decode functions for the new variant without touching any existing variant's wire layout - _Requirements: 6.1, 6.2_ - _Boundary: Compact Scheduler/API-Server Push_ - [x] 1.3 (P) jobj.c hardening - Make job construction check the interning/string-construction return value and propagate failure instead of silently storing a NULL success - Root-cause and fix the previously observed construction-table initialization-ordering gap; if root-causing shows the actual gap is outside this file's own init/call ordering (e.g. controller boot sequencing), stop and flag it as a separate follow-up rather than forcing a fix into this task's boundary - Verify (with a test) that the destructive-move fields on a freshly-built job payload are always NULL, so repeated use against a shared template is provably benign - Fix the known leak on job teardown for the one field that was never freed - Verify (with a test) that the field claimed to be an undocumented leak risk actually has no wire representation to leak in the first place - Observable: a new construction-failure path returns an error instead of a silently-broken success; the leak-fix is visible under a leak-detection test run; all five items have a passing test each - _Requirements: 10.1, 10.2, 10.3, 10.4, 10.5_ - _Boundary: jobj.c Hardening_ - [ ] 2. WAL Array Submission: encode, append, commit - [x] 2.1 Implement the single-record array append and commit path - Encode one compact payload carrying (base jobid, array size, one shared job spec) — the same shape as the client's own submit request - Append it as exactly one `WAL_JOB_ARRAY_SUBMIT` WAL entry and register exactly one commit continuation for it, regardless of array size - Observable: submitting an array produces one WAL append call and one registered commit continuation in a controlled test, not one per element - _Requirements: 1.1, 1.2, 1.3, 4.2, 9.2_ - _Boundary: WAL Array Submission_ - [x] 2.2 Wire array submissions into the request handler - Branch the submission handler on array size: exactly 1 continues through today's existing single-job code path completely unmodified; greater than 1 routes to 2.1's single-append path - Preserve the existing pre-commit range validation (collision check plus in-flight claim) unchanged and in the same order, still rejecting strictly before any WAL append - Reuse the existing batched-reply mechanism, setting it to expect exactly one outcome instead of one per element - Observable: a single-job submission (array size 1) is byte-identical in behavior to before this feature; an array submission returns exactly one reply after exactly one outcome resolves - _Requirements: 1.1, 1.2, 1.3, 8.1, 9.1, 9.2_ - _Boundary: WAL Array Submission_ - _Depends: 1.1_ - [x] 2.3 Unit tests for the array append/commit path - Verify exactly one WAL entry and one commit continuation are produced for an array submission, for several array sizes - Verify the encoded payload's size does not grow with array size (stays constant regardless of element count) - Verify a single-job (array size 1) submission produces a byte-identical WAL record, commit-barrier count, and reply compared to the pre-feature baseline - Observable: a passing test suite demonstrating all three properties above - _Requirements: 1.1, 1.2, 1.3, 7.1, 7.2, 8.1_ - _Boundary: WAL Array Submission_ - [ ] 3. Array Apply Expansion: shared N-way expansion and dispatch wiring - [x] 3.1 Implement the shared array expansion primitive - Decode the committed array payload and, for each index in the array's range, build a job entry without yet making it visible to any reader - Skip building an entry for any index that already exists (idempotent re-apply); if every index already exists, treat the whole record as an already-applied no-op - Once every index has successfully built, make the whole set visible in one atomic step; if any index fails to build, discard everything built in this attempt without ever making any of it visible — a retry starts over from the first index - Include a test-only, forceable failure point (compiled out in production) that a test can use to force a failure at a chosen index - Observable: a test can force a mid-array failure and confirm zero elements are visible afterward, then force success and confirm the full set becomes visible in one step - _Requirements: 2.1, 2.2, 2.3, 3.3, 4.1, 5.1, 5.2, 5.3, 9.3, 9.6_ - _Boundary: Array Apply Expansion_ - _Depends: 1.3_ - [x] 3.2 Wire array expansion into live apply - Call 3.1's primitive from the live-apply/boot-replay dispatch path for the new WAL record type - After a successful expansion, fire the existing job-created notification exactly once, carrying every newly created element in one list — never once per element - Observable: applying one committed array record produces exactly one notification event carrying all N elements - _Requirements: 3.1, 3.4_ - _Boundary: Array Apply Expansion_ - [x] 3.3 Wire array expansion into standby catch-up (defensive parity — see note below) - Call 3.1's same primitive from the separate standby catch-up/replicated-apply dispatch path for the new WAL record type, without firing any notification (matching that path's existing hook-free behavior for the single-job case) - Observable: a test applies the same committed array record through both the live-apply dispatch and the standby catch-up dispatch and confirms byte-identical resulting job state either way - _Requirements: 3.1, 3.2, 4.1 — delivered by task 3.2 alone (see Implementation Notes); this task is defensive parity, not an independent delivery path_ - _Boundary: Array Apply Expansion_ - [x] 3.4 Unit tests for array expansion - Verify N-way expansion produces the correct contiguous set of element identities for several array sizes - Verify idempotent re-apply of an already-fully-applied record is a no-op that creates nothing new - Verify, using 3.1's forceable failure point, that a failure partway through leaves nothing visible, and that a subsequent successful retry produces the complete, non-duplicated set - Observable: a passing test suite covering all three properties above - _Requirements: 2.1, 2.2, 2.3, 3.3, 5.1, 5.2, 5.3, 9.4, 9.6_ - _Boundary: Array Apply Expansion_ - [ ] 4. Live Apply Resource Fence - [x] 4.1 Make the apply pump respect apply failures - Stop discarding the array-expansion (and every other WAL type's) apply outcome; on a failure, halt the apply walk at that position without advancing past it, and log a loud, operator-visible error naming the stuck position - Observable: a simulated apply failure at a given position causes the walk to stop exactly there and not proceed to later entries - _Requirements: 9.4_ - _Boundary: Live Apply Resource Fence_ - [x] 4.2 Add the live, self-healing fence - Add a new piece of state (distinct from the existing boot-only unrecoverable-fence flag) recording "a position is currently stuck failing to apply" - Engage it when 4.1's halt condition triggers; clear it automatically, from inside the apply walk itself, the moment a retry of that same stuck position succeeds - Observable: after a forced failure the new state reads "fenced"; after the same position later succeeds on retry, the state reads "clear" without any external action - _Requirements: 9.4, 9.5_ - _Boundary: Live Apply Resource Fence_ - [x] 4.3 Gate promotion on the live fence - Add the new fence state as a required condition at both existing points where a node's eligibility for promotion is decided (the periodic release check and the election-time check) - Observable: a node with the fence engaged is refused promotion at both points; once the fence clears, the node is eligible again without any other change - _Requirements: 9.4, 9.5_ - _Boundary: Live Apply Resource Fence_ - [x] 4.4 Fault-injection test for the live fence - Using 3.1's forceable failure point, force a resource-exhaustion-style failure during array expansion and verify: the node fences itself and is refused promotion, constructs no partial or divergent set of elements, does not affect any other (simulated) node's independent progress, and self-heals — clearing the fence and completing the apply — once the forced condition is removed and the retry succeeds - Observable: a single passing test exercising the full engage-refuse-clear-recover sequence - _Requirements: 9.4, 9.5, 9.6_ - _Boundary: Live Apply Resource Fence_ - _Depends: 3.1_ - [ ] 5. Compact Scheduler/API-Server Push - [x] 5.1 (P) Build the compact scheduler push - Add a function that encodes the compact (base jobid, array size, one spec) message for the scheduler and branch the existing job-created push handler to call it, instead of the existing per-job push, whenever the notification carries more than one element - Leave the single-element (ordinary single-job) branch completely unmodified - Observable: a synthetic multi-element notification produces exactly one compact push call, not N individually-encoded job structs; a synthetic single-element notification is unaffected - _Requirements: 6.1, 6.3, 6.4_ - _Boundary: Compact Scheduler/API-Server Push (controller-side scheduler push)_ - [x] 5.2 (P) Build the compact API-server push - Same construction as 5.1, for the API-server push handler and its own existing per-job push - Observable: a synthetic multi-element notification produces exactly one compact push per connected API server, not N individually-encoded job structs; the single-element branch is unaffected - _Requirements: 6.2, 6.4_ - _Boundary: Compact Scheduler/API-Server Push (controller-side apiserver push)_ - [x] 5.3 (P) Scheduler-side local expansion - Decode the compact push and expand it locally into N ordinary schedulable tasks using the same base-jobid-plus-index arithmetic the controller itself uses - Deduplicate by element identity so a redelivered push (e.g. after a scheduler reconnect) does not create duplicate tasks - Log one identifiable confirmation line (base jobid plus element count) once expansion completes - Observable: feeding the same compact push twice to the receiver produces the task set once, not twice, and exactly one confirmation log line per successful expansion - _Requirements: 6.3, 6.4, 6.5, 8.4_ - _Boundary: Compact Scheduler/API-Server Push (scheduler daemon receive path)_ - _Depends: 5.1_ - [x] 5.3b Fix the shared wire dispatcher to carry the compact array push - `extract_data()` (`src/lib/request.c`) is the shared reassembly step every inbound push (scheduler and API-server alike) passes through inside `vtask_entry()` (`src/lib/xcectx.c`) before a receiver's handler ever runs. Its dispatch switch has no case for the `Data_data_jobArray` variant (added task 1.2) and falls into `default: rc = -EINVAL`. Because `vtask_entry()`'s `if (callnext)` treats ANY nonzero return — including a negative errno — as "reassembly complete, proceed," this doesn't surface as an error: the real payload is freed and the receiver is silently handed an empty, zeroed `dataset_t` (`rows=NULL, nrows=0`), with no log anywhere in the chain (`vtask_entry()` discards the handler's own return value unconditionally) - Add a `case Data_data_jobArray:` to `extract_data()` that passes the single, unchunked `JobSubmit` descriptor straight through to the caller's `dataset_t` — no pagination/accumulation loop is needed (unlike the existing LIST-shaped cases), since this push is always exactly one descriptor per commit, matching the "wire shape note" both `xcesched_push_jobarray()` (task 5.1) and `apiserver_push_jobarray()` (task 5.2) already establish - Confirms both the scheduler (task 5.3, already landed) and the future API-server Go receiver (task 5.4) share this exact fix — this task only needs to land once - Observable: a synthetic `Data_data_jobArray` push driven through the REAL `vtask_entry()`/`extract_data()` path (not task 5.3's white-box `sched_handle_dataset()`-direct test) reaches the scheduler's `sched_on_job_array()` with the genuine payload intact, not an empty dataset - _Requirements: 6.1, 6.2, 6.4, 8.4_ - _Boundary: shared wire transport (`src/lib/request.c`, `src/lib/xcectx.c`) — out of the Compact Scheduler/API-Server Push component's original File Structure Plan; discovered during task 5.3's review (2026-07-15), design.md corrected to record it_ - _Depends: 5.1, 5.2_ - [x] 5.4 (P) API-server-side local expansion - Decode the compact push and expand it locally into N per-element records using the same base-jobid-plus-index arithmetic - Deduplicate by element identity so a redelivered push does not create duplicate records - Log one identifiable confirmation line (base jobid plus element count) once expansion completes - Observable: feeding the same compact push twice to the receiver produces the record set once, not twice, and exactly one confirmation log line per successful expansion - _Requirements: 6.2, 6.4, 6.5, 8.4_ - _Boundary: Compact Scheduler/API-Server Push (apiserver receive path)_ - _Depends: 5.2_ - [x] 5.5 Integration test: end-to-end compact push - Commit one array record end-to-end and confirm the scheduler and the API server each receive exactly one push and each expand it into N correctly-addressable entries - Confirm a simulated redelivery (reconnect) to either receiver does not double-expand - Observable: a passing integration test covering both receivers' one-push/N-entries/no-double-expand behavior, including both receivers' confirmation log lines - _Requirements: 6.1, 6.2, 6.3, 6.4, 6.5, 8.4_ - _Boundary: Compact Scheduler/API-Server Push_ - [ ] 6. Integration & non-regression soak - [x] 6.0a Fix replay_wal()'s job-count tally for WAL_JOB_ARRAY_SUBMIT - `replay_wal()` (`src/controller/persist.c` ~3902) tallies `*new_job_submits_out` only for `hdr.type == WAL_JOB_SUBMIT`. `WAL_JOB_ARRAY_SUBMIT` (task 1.1) is dispatched to `apply_committed_entry()` and correctly materializes N real jobmgr entries, but contributes 0 to this tally. `persist_verify_apply_correctness()` then compares real jobmgr growth (correct, N-sized) against the undercounted expectation, produces a false `APPLY_DIVERGENT` verdict, and engages `persist_recover_loud_fence_if_unrecoverable()` — a PERMANENT, non-self-healing fence (distinct from task 4.2's Live Apply Resource Fence, which self-heals; this one has no live-clear path short of a later restart landing after a checkpoint advances past the array's LSN) - Live-reproduced during task 6.1's soak attempt (2026-07-15) on 2 of 3 nodes in a single small-array (N=2) sub-round, via two different trigger paths (ordinary boot-time `persist_recover()`, and a standby's election-path recovery fallback) — confirmed deterministic, not racy, not size-dependent. A pre-existing comment at persist.c ~3863-3874 (predates this spec, from `raft-apply-decoupling` task 2.3) already flagged this exact code region as needing re-verification "before tasks 4.1/6.1/6.2/6.3 make this path broadly live" — this is that re-verification, and it failed - Fix: add a `WAL_JOB_ARRAY_SUBMIT` branch to the tally that adds `apply_rc` (the genuine new-element count `apply_committed_entry()`'s array case already returns) to `*new_job_submits_out` when `apply_rc > 0`, mirroring the existing dedup-safe pattern used for `WAL_JOB_SUBMIT` - Observable: the exact live-soak reproduction (small array submit, then restart/re-elect a node) no longer produces `APPLY_DIVERGENT`; the node boots/rejoins cleanly and remains promotable - _Requirements: 3.1, 3.2, 4.1, 9.4_ - _Boundary: Array Apply Expansion (`persist.c`'s replay-side job-count accounting) — discovered during task 6.1's soak (2026-07-15), inserted per explicit user decision; blocks 6.1/6.2/6.3, all of which require a cluster that survives a restart after an array submission_ - [ ] 6.1 Large-array soak scenario - Extend the existing HA soak harness with a large-array submission scenario asserting: one WAL record and one commit barrier regardless of array size, failover replay time governed by the record's size rather than element count, and every array element individually addressable (status, cancel, completion) after a failover - Observable: a soak run reporting the one-record/one-barrier assertion, a replay-time measurement independent of array size, and successful per-element status checks post-failover - _Requirements: 4.3, 5.2, 5.3, 8.2, 8.3_ - _Boundary: Non-Regression & Testing_ - _Depends: 6.0a_ - [ ] 6.2 Chaotic-failover array retry scenario - Extend the soak harness with a scenario submitting an array immediately before killing the primary, then retrying the identical submission against the new primary - Assert the retry follows the same cross-primary dedup mechanism as single-job submission, extended to the array's full index range as one unit, and does not double-submit or partially duplicate - Observable: a soak run showing the retried array resolves to exactly one committed instance of the array, with no partial duplication - _Requirements: 8.2, 8.3_ - _Boundary: Non-Regression & Testing_ - [ ] 6.3 Full regression pass - Run the complete existing unit, integration, and soak suite (sequential and chaotic) and confirm zero new job loss, divergence, or liveness stall attributable to this feature - Confirm the non-array (array size 1) WAL format, commit-barrier count, and reply are byte-identical to the pre-feature baseline - Observable: a clean full-suite run with the byte-identical single-job baseline check passing alongside it - _Requirements: 8.1, 8.2, 8.4_ - _Boundary: Non-Regression & Testing_ ## Implementation Notes - **Task 1.3**: `meson test --suite xce`'s `libxce test` target SIGABRTs under ASAN leak detection whenever any code path exercises a `job_init()` failure — root cause is the vendored `rtti` library's `makeInstance()` not freeing its allocation when a type's `.init()` returns negative (no `.c` source available, headers-only in the nix store). This is pre-existing and independently reproduced against an unmodified pre-task `jobj.c`, not introduced by this feature. It will fire again on any future task whose tests exercise a `create_job()`/`makeJob()` failure path (e.g. task 3.1/3.4's fault-injection tests for `restore_job_array()`) — expect the same SIGABRT-not-assertion-failure signature (`grep ":FAIL"` on the Unity log will be empty; the failure is LeakSanitizer-only) and do not treat it as a new regression without the same stash-and-reproduce check task 1.3's review used. - **Task 1.3**: `job_obj_init()`/`job_obj_fini()` are now idempotent (atomic_flag-guarded) — safe to call more than once without an intervening `fini()`. Any future test construction can rely on this instead of coordinating a single call site. - **Task 1.3**: `makeJobsub()`/`makeJobstartinfo()` now return `-ENODEV` (not a generic `-EINVAL`) when the interning table isn't initialized — if a later task's error handling branches on `job_init()`'s return value, `-ENODEV` is a distinct, checkable signal for "table not ready" vs. other construction failures. - **Task 3.3**: `apply_wal_entry()` (persist.c:2574) is dead code in production — confirmed via exhaustive grep (zero call sites outside its own declaration/definition/comments) and via `ha.c:8024`'s `ha_standby_advance_committed_and_apply` (dated 2026-07-10), whose own doc comment explicitly says standby entity materialization now goes through the SAME `apply_committed_entry()`/`persist_apply_pump_kick` pump the primary uses, not `apply_wal_entry()`. The persist.c:3722 comment claiming otherwise predates that refactor and was never updated (design.md corrected accordingly). Requirement 3.1/3.2/4.1 are fully delivered by task 3.2 alone. Task 3.3's code was kept (not discarded) as defensive parity with `WAL_JOB_SUBMIT`'s existing, also-dead case in the same switch — it is tested and correct, just not currently reachable in production. If `apply_wal_entry()` is ever revived or removed entirely in a future spec, this task's case should move or be deleted with it. - **Task 3.1**: `restore_job_array()`'s atomicity has one narrow, documented exception (design.md updated to match): the final bulk-insert-into-`c->jobmgr` pass can itself fail on allocation/growth exhaustion (`c->jobmgr` grows via `realloc()`; no capacity-reservation primitive exists anywhere in `kv.c`/`kvmgr.c`/`zarray.c` to pre-check this before mutating). On this specific failure, the function never silently claims success — it returns a negative errno — but an already-inserted prefix `[0, inserted)` can be left genuinely, permanently visible in `c->jobmgr` (no `key_del` exists to undo it), and that prefix is NEVER included in `out_new_jobs`, so `HOOK_DETAIL_JOB_NEW` never fires for it, not on this attempt or any later successful retry of the same LSN. **Tasks 3.2/4.x must account for this**: those elements are individually addressable (status/cancel/completion work normally) but permanently un-pushed to the scheduler/API server unless something later re-derives and re-notifies them — this is a real gap in the current design, not yet solved, and task 4.x's Live Apply Resource Fence design should explicitly decide whether/how to handle it (e.g. detecting this residual state and re-notifying on self-heal) rather than only handling the construction-phase failure case. **UPDATE (post-4.4): this gap was NOT closed by Phase 4.** Tasks 4.1-4.4 correctly deliver the generic negative-rc halt/fence/gate/self-heal machinery — a bulk-insert-phase failure DOES still engage the fence and block promotion, same as any other failure — but none of them add the "no partial/divergent set" guarantee specifically for this seam, because that guarantee is structurally false on this path with current APIs (no `key_del`). Task 4.4's own capstone test deliberately used the (fully atomic) construction-phase seam instead, precisely because asserting "zero partial elements" against the bulk-insert seam would be dishonest. **This residual gap remains open and unowned by any task in this spec's current scope** — flag at `/kiro-validate-impl` time; closing it would require either a `key_del`/rollback primitive in `kv.c`/`kvmgr.c`, or a re-derive-and-re-notify recovery path for the orphaned prefix, either of which is design-level work beyond this spec's approved task list. - **Task 4.1**: `persist_apply_pump_run()` now halts the walk (no `last_applied_lsn` advance) on ANY negative return from `apply_committed_entry()`, not just the new array type — this is a general fix. Investigated whether this newly exposes a hazard for the pre-existing job-state fact entries (`WAL_JOB_START/FINISH/FAIL/UPDATE`), which have their own real `-ENOENT` branch when the target jobid isn't in `c->jobmgr`: confirmed NOT a hazard, because `c->jobmgr` (`xkvmgr_type`) has no `key_del` (jobs are never removed for the process lifetime, corroborated by `job.c:428,455,645`), and this task's own strict sequential-no-skip apply means a fact's LSN is only reached after its causally-prior submit already applied. So a live `-ENOENT` on a fact can now only mean genuine corruption/divergence — halting is correct, not a new footgun. Independent reviewer confirmed this via `test_term_safety_adapter.c:2039-2043`'s synthetic (non-production-representative) trigger. design.md's "Existing Architecture Analysis" table row overclaims ("every existing WAL type... returns 0 or positive in practice") — technically inaccurate re: the fact-ENOENT branch — left as-is since the persist.c code comment at the site already documents the exception correctly; low-severity, non-blocking. - **Task 4.2**: New `_Atomic uint64_t apply_resource_fenced_lsn` field on `persist_t` (0 = clear, nonzero = the stuck LSN) plus `persist_apply_resource_fenced()`/`persist_mark_apply_resource_fenced()`/`persist_clear_apply_resource_fence()`, wired into `persist_apply_pump_run()`'s existing halt branch (engage) and unconditionally after every successful advance (clear). The unconditional clear is provably equivalent to "clear only on the fenced LSN's own successful retry" because `last_applied_lsn` has exactly 3 writers codebase-wide, the other two (`replay_wal`, `persist_recover`) are boot-only and temporally disjoint from the live pump, and a failed walk never advances past the stuck LSN — so the next success by construction IS that LSN's retry. **Known residual gap (out of this task's boundary, flagged by review, NOT yet fixed)**: `replay_wal()` (boot/restart replay, persist.c:3875-3888) still discards `apply_committed_entry()`'s failure return the same way the live pump did before task 4.1, and `persist_init()` unconditionally zeroes the fence field on every restart. A node that crashes while fenced and re-hits the identical resource-exhaustion condition during boot replay will silently pass it and look fully promotable while actually divergent — task 4.1/4.2's protection does not yet extend to the boot-replay path. This is a pre-existing gap (not introduced by this feature) but is now inconsistent with the live path's new guarantee; worth a dedicated follow-up task before anything downstream places full trust in this fence across a restart. - **Task 5.1**: New `xcesched_push_jobarray()` (`sched.c`) sends via direct `xce_request()`/`OPCode_push`/`Request_body_pushmsg` rather than the existing `xce_push_data_req()` helper — `xce_push_data_req()`'s dispatch switch hard-rejects (`-EINVAL`) anything outside jobs/workers/resources/resvals, so it cannot carry a single non-list `Data.jobArray` descriptor. design.md corrected to match (Dependencies + API Contract for the Compact Scheduler/API-Server Push component). Task 5.2's API-server push will hit the identical fork and should follow the same direct-`xce_request()` pattern rather than re-deriving it. One accepted, low-severity trade-off: the direct path does not go through `xce_push_data_req()`'s `checkf`-gated `check_controller`/`c->running` liveness check that every other push gets — a narrow shutdown-race behavioral difference from sibling pushes, not a new safety hazard; not fixed here since threading a liveness check into a single new call site duplicates rather than reuses the shared gate. `sched.c`/`dataex.c`/`egress.c` were never linked into `controller_unit_test` (two existing test files there ship their own fake `on_scheduler_join()`/`notify()`/`collect_confvars()` precisely because of this, and linking the real ones would collide) — task 5.1's tests live in a new standalone `sched_push_unit_test` binary instead; task 5.2 will likely face the same fork for `apiserver.c` and should check for an analogous existing-fakes collision before choosing a test-binary strategy. - **Task 5.2**: `apiserver_push_jobarray()` (`apiserver.c`) mirrors task 5.1's `xcesched_push_jobarray()` exactly — same field derivation, same direct-`xce_request()` transport, same `l->count > 1` discriminator — and additionally, correctly replicates `apiserver_push_joblist()`'s existing per-connected-server fan-out loop (`N_APISERVER_MAX` iteration, same lock discipline), independently verified against 2 simulated connected servers each receiving exactly one push. Confirmed the same `apiserver.c`/`dataex.c` link-collision task 5.1 hit for `sched.c` (a fake `notify()` already exists in `test_commit_barrier_reply.c`) — new standalone `apiserver_push_unit_test` binary added, correctly omitting `egress.c` since `apiserver_push_joblist()`, unlike `sched.c`'s push path, never references `job_submit_committed()`/`collect_jobs_committed()`. One low-severity, non-blocking nit (not fixed): the new test file's comment justifying its `apiserver_init()` idempotency guard is factually inaccurate — it claims a second `apiserver_init()` call would double-register hooks, but `xce_add_hook()` has deduped by `(fn,data)` since bug-845, so that specific claim is wrong; the guard itself is still correct/necessary for a different, real reason (avoids re-`mylock_init()`-ing an already-initialized mutex, UB). - **Task 5.3**: `sched_on_job_array()` (`handler.c`) decodes `Data_data_jobArray`, derives each element's jobid via `base_jobid + i`, and routes constructed elements through the unmodified per-job pipeline (`sched_on_jobs()`). Each element gets its OWN deep clone (`clone_job_submit_data`/`clone_job_startinfo`) of the shared submit spec — required because `sched_pend_update_killer()`'s per-element teardown (`free_Job_ptr`) frees each element's `submit` independently and a shared pointer across N elements would double-free; independently verified. Dedup reuses `sched_get_job()` against the same `sched->jobs` kvtab `sched_add_job()`'s `key_add` authoritatively guards — sound at the data-integrity level, but review found a narrow, non-corrupting TOCTOU: the dedup pre-check runs synchronously at receive time while the actual insert only happens later when `sched_update()` drains `pend_updates[0]`, so a redelivery landing before that drain can re-construct/re-enqueue a duplicate (harmless) object and double the confirmation log line — the same pre-existing, task-5.3-unrelated pattern as `sched_update_jobs()`'s already-ignored `key_add` `-EEXIST` return on the ordinary single-job path. Not fixed (pre-existing class of gap, narrow window, non-corrupting). **CRITICAL discovery during this task's review (2026-07-15), NOT a defect in task 5.3 itself**: the shared wire dispatcher `extract_data()` (`src/lib/request.c`) has no case for `Data_data_jobArray` and silently drops every real array push before ANY receiver's handler runs (see new task 5.3b, inserted immediately after this task per explicit user decision). Confirmed to affect task 5.4's future API-server receive path identically (both share the same `xcecli_ctx_init()` → `vtask_entry()` → `extract_data()` pipeline). Task 5.3's own tests are unaffected by this gap since they use the same established white-box convention as every sibling `handler.c` test (calling `sched_handle_dataset()` directly, bypassing the transport layer) — this is not a new testing shortcut, it just means task 5.3's passing tests do not, and were never intended to, prove real-wire delivery. - **Task 5.3b**: Added `case Data_data_jobArray:` to `extract_data()` (`request.c`) — sets `dataset->rows`/`nrows=1` directly (no pagination, matching the always-one-shot wire shape) and nulls `getdata->data.job_array` after transferring it. The null is NOT cosmetic — independently verified `free_Request()`'s `Request_body_pushmsg` case calls `free_Data()`, which has a live `Data_data_jobArray` branch that would double-free/UAF without it. Proven end-to-end with a real `xce_encode()`/`xce_decode()` round-trip through `extract_data()` → `sched_handle_dataset()` → `sched_on_job_array()` (task 5.3, unmodified), not just a unit-level check. Also independently confirmed the alternate hypothesis some earlier notes floated — that `scheduler_req_handler()` itself has a `pushmsg`-rejecting branch — is dead code on the live wire path, since `vtask_entry()` always converts `body_which` to `datamsg` before invoking any handler. **New residual gap, self-flagged, NOT fixed (pre-existing since task 5.3, not introduced here, genuinely out of this task's `request.c`-only boundary)**: `dataset->rows` for the jobArray case is never deep-freed downstream — `free_Dataset()` is an empty no-op for all table types, and `sched_handle_dataset()`'s jobArray case (task 5.3) doesn't null it after consuming it. Net effect: one bounded `xce_job_submit_t` + embedded spec leaks per successfully-delivered array push commit (not per element, not unbounded) — real but small; worth a dedicated follow-up before this spec is considered fully closed, alongside the other self-flagged residual gaps (task 3.1's bulk-insert orphan prefix, task 4.2's boot-replay fence gap). - **Task 5.4**: Go/CGO receive path — `rawJobArrayToModels()` (pure-Go N-way expansion), `cJobArrayToModels()` (CGO adapter sibling to `cJobToModel`), `dispatchJobArray()` (dedup via the SAME `store.Jobs.Has()` the ordinary `Data_data_jobs` path writes through, one confirmation log only on ≥1 newly-dispatched element), new `case C.Data_data_jobArray:` in `handleDataset`. Elements route through `OnJobUpdated` (not `OnJobCreated`), matching the ordinary single-job push's own routing — verified consistent, not a divergence. CGO boundary needed zero changes — `C.xce_job_submit_t` and `C.Data_data_jobArray` were already exposed/generated from prior tasks. A structural TOCTOU exists between the `Has()` dedup check and the eventual store write (two separate lock acquisitions, no compare-and-set primitive) but is narrower than task 5.3's accepted C-side gap (no intervening async hop) and strictly safer than the pre-existing baseline (the ordinary `Data_data_jobs` path has NO dedup check at all today) — not fixed, judged acceptable. `cJobArrayToModels()` has zero direct unit coverage at the CGO-struct level, but this exactly mirrors the pre-existing, repo-wide precedent for `cJobToModel()` itself (also never unit-tested with a real C struct) — reviewer independently reconstructed a full `CGO_ENABLED=1` build+link+test run against the real generated headers to confirm correctness beyond a compile-only check. `store.ArrayJobs` (array-level rollup aggregate) deliberately left unpopulated — confirmed genuinely out of this spec's scope per requirements.md's Boundary Context, which explicitly defers whole-array bulk query/cancel to a future spec; zero code anywhere in the codebase populates it today, including this diff. - **Task 5.5**: Cross-daemon integration test, test-only (zero net production diff, confirmed on `request.c` and every task 5.1-5.4 file). Drives real `xce_encode()`/`xce_decode()` wire bytes through the REAL production dispatch chain on both daemons — `extract_data()` → `scheduler_req_handler()` → `sched_handle_dataset()` → `sched_on_job_array()` (C, via `#include "../src/handler.c"` in the test) and `go_push_handler()` → `handleDataset()` → `cJobArrayToModels()`/`dispatchJobArray()` (Go/CGO) — skipping only `vtask_entry()`'s ~10 lines of `static` glue, which the test mirrors verbatim (independently verified line-by-line accurate on the one behavior that mattered: `if (callnext)` treating any nonzero `extract_data()` return, including a negative errno, as "proceed"). Redelivery is tested via genuinely independent fresh decodes of separately-encoded bytes, not a cheaper decode-once-call-twice shortcut. Bug-catching capability independently proven twice (implementer, then reviewer): temporarily reverting task 5.3b's fix makes both the C and Go tests fail meaningfully; restoring returns both to green. Go/cgo toolchain constraint discovered: `import "C"` is disallowed in any `_test.go` file, forcing a two-file split (`wire_dispatch_support.go` for cgo-preamble helpers, `wire_dispatch_test.go` for the actual tests) — logged as bug-1440/1441/1442. One low-severity, non-blocking nit (not fixed): the C test file's own header comment misdescribes which assertion fails first under the RED-phase revert (claims the `callnext != 0` check; actually a downstream `>= 0` check) — cosmetic only, the test's real bug-catching property is independently confirmed accurate. - **Task 6.0a**: Fixed `replay_wal()`'s job-count tally (persist.c ~3902) to add a `WAL_JOB_ARRAY_SUBMIT` branch that tallies `apply_rc` (the genuine per-record element count `apply_committed_entry()`'s array case already returns) when `apply_rc > 0`. Independently traced the FULL return-value space of `restore_job_array()`/`apply_committed_entry()`'s array case (6 distinct cases: 3 negative pre-mutation failures, `-EEXIST`→`apply_rc=0` idempotent no-op, the task-3.1 bulk-insert partial-failure case (stays negative, correctly still NOT tallied — a pre-existing, out-of-boundary undercount that still surfaces as a detectable anomaly rather than masking one), and positive `created` on genuine success) and confirmed every positive `apply_rc` this fix tallies is PROVABLY equal to real jobmgr growth for that record — the fix cannot overcount, and therefore cannot weaken `persist_verify_apply_correctness()`'s ability to catch a genuine divergence. Verified end-to-end via a from-scratch live 3-node HA soak re-run (`--array-soak`, both by the implementer and independently by the reviewer): zero `APPLY_DIVERGENT` across all three of the original bug's trigger paths (restart-mid-small-array, standby election-path recovery fallback, restart-mid-N=10000-array), one-WAL-record/one-commit-barrier confirmed for both N=2 and N=10000, per-element post-failover status/cancel/completion confirmed. This soak run also directly satisfies task 6.1's own Observable — its results should be reused rather than re-run from scratch. **New non-blocking finding (pre-existing, NOT introduced by this task)**: `controller_unit_test`'s single outer `UNITY_BEGIN()` is silently reset by ~19 of its called test-group functions' OWN nested `UNITY_BEGIN()/UNITY_END()` calls, making the process exit code / meson `Ok:/Fail:` summary line unreliable for detecting a regression in any group running before the last such nested call — both the implementer and reviewer worked around this by grepping raw `testlog.txt` for `:FAIL:` lines directly rather than trusting the summary, and this should be the standard practice going forward for this binary until a dedicated follow-up fixes the harness itself.