myxce/.wolf/bugs/bug-1944.md

id	status	status_updated	status_note	component	severity	timestamp	last_seen	occurrences	files	tags	related	fix_commits	gitea_issue	gitea_synced_status	gitea_synced_hash
bug-1944	fixed	2026-10-10		scheduler	wrong-result	2026-10-10T08:14:56Z	2026-10-10T08:14:56Z	1	src/scheduler/src/core_events.c src/scheduler/src/schedobj.c	scheduler queue priority		7a9d75d6	375	fixed	69bd8ab4a2cc

bug-1944: xce_scheduler gives a job moved to another queue the queue's priority, so it jumps ahead

Description

Observed: (source reading, .kiro/reviews/project-gap-review-2026-10-10.md (P0); to be confirmed by a failing test before the fix) New jobs get priority 0 (schedobj.c:214, core_events.c:353), but on a queue change the job's priority becomes the queue's priority (core_events.c:1360, schedobj.c:684); the picker sorts by job priority within a queue (plugins/builtin_fcfs.c:213).

Expected: Moving a job does not change its job priority. Impact: Wrong ordering: moved jobs overtake jobs submitted earlier to the target queue. Found by: review: .kiro/reviews/project-gap-review-2026-10-10.md (P0)

Environment

• OS: no /etc/os-release; Docker container; NixOS kernel; kernel Linux 6.18.33 x86_64
• libc: glibc 2.42-47 (interpreter /nix/store/wb6rhpznjfczwlwx23zmdrrw74bayxw4-glibc-2.42-47/lib/ld-linux-x86-64.so.2)
• Toolchain: gcc (GCC) 15.2.0, meson 1.9.1
• Build: asan (xce.build)
• Code: scheduler-framework @ 94472ee3-dirty
• Deployment: any (found by source reading; the failing test that confirms it is named in Verification)

Reproduction

1. Two jobs pending in queue B; move a third job from A to B (queue priority > 0).
2. The moved job is picked first.

• Frequency: deterministic (by code reading; confirmed by the RED test of the fix)
• Evidence: the code sites quoted in Description; no logs kept.

Root cause

On a queue change both xce_core_push_events (JOB_UPDATE, core_events.c) and sched_update_existing_job (schedobj.c) set job->priority = q->priority; new jobs and snapshot-restored jobs get 0, so moved jobs jumped ahead and live/replay disagreed. Pre-existing.

Fix

Both sites now only re-point job->queue on a move; queue priority still orders the queues. test_job_update.c, which asserted the old behaviour, now expects the job's own priority.

Verification

• Test: test_moved_job_keeps_its_priority_and_place (src/scheduler/testsuite/test_job_move_priority.c): RED :208: FAIL: Expected 0 Was 10 (and :214: Expected 2 Was 1 for the ordering), GREEN after; test_update_existing_job_mutates_in_place RED Expected 1 Was 5 with the corrected expectation, GREEN after.
• Suites: xce-build.sh all asan xce.build --incremental on the merged branch, 2026-10-10: all C suites Ok 155 / Fail 0, frontend Go unit tests ok, xceadmin tests ok; apiserver CGO_ENABLED=0 go test ./... (incl. middleware, router, cmd) ok
• Live: n/a: unit/fixture-level verification only; no live deployment was run (follow-up)

References

• Fix commit: 7a9d75d6 (on scheduler-framework; worker-branch original in the merge)
• Review: .kiro/reviews/project-gap-review-2026-10-10.md