myxce/.wolf/bugs/bug-1943.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-1943	fixed	2026-10-10		scheduler	wrong-result	2026-10-10T08:14:54Z	2026-10-10T08:14:54Z	1	src/scheduler/src/core_events.c src/scheduler/src/scheduler.c	scheduler sim equivalence limit		8b89a0ce	374	fixed	68ef4f5dc713

bug-1943: xce_scheduler --sim does not load user and host groups, so group-scoped limits differ from live

Description

Observed: (source reading, .kiro/reviews/project-gap-review-2026-10-10.md (P0); to be confirmed by a failing test before the fix) On a config push the live scheduler loads user and host groups (groupmgr_load_configs, src/scheduler/src/scheduler.c:1144-1145); the core's config event used by the simulator applies only resources, resource values and queues (core_events.c:846-850).

Expected: Live and simulated scheduling apply the same groups (scheduler-driver-equivalence.md). Impact: Replays of clusters with group-scoped limits make different decisions than the live scheduler. 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. Record a session with a limit scoped to a user group, replay it with xce_scheduler --sim.
2. The limit does not match the group's users in sim.

• 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

Only sched_init_config() (scheduler.c, live) called groupmgr_load_configs; the core CONFIG_PUSH event (core_events.c:xce_core_push_events) and the replay snapshot loader (snapshot_load.c:xce_sched_core_load_snapshot, from which sim_bootstrap_limit_plugin seeds limits) never loaded groups. Pre-existing.

Fix

core.h/core.c: new xce_core_load_groups() is the single loader, called from sched_init_config() (replacing its direct calls), the CONFIG_PUSH event (first) and snapshot_load.c (before the limit plugin is seeded); snapshot.c field-completeness note updated. Follow-up: limits are not re-seeded on a mid-replay CONFIG_PUSH.

Verification

• Test: test_user_group_limit_matches_in_sim_as_in_live (src/scheduler/testsuite/test_sim_group_limit_parity.c): RED :318: FAIL: Expected 1 Was 0 (sim must match the user-group-scoped limit), and with only the CONFIG_PUSH part reverted :334: FAIL: CONFIG_PUSH must register the config's user groups, 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: 8b89a0ce (on scheduler-framework; worker-branch original in the merge)
• Review: .kiro/reviews/project-gap-review-2026-10-10.md