---
id: "bug-1933"
status: "fixed"
status_updated: "2026-10-10"
status_note: ""
component: "scheduler"
severity: "wrong-result"
timestamp: "2026-10-10T03:36:53Z"
last_seen: "2026-10-10T03:36:53Z"
occurrences: 1
files: ["src/scheduler/src/plugins/limit.c", "src/lib/xcelimit.c"]
tags: ["scheduler", "limit", "project", "hostgroup"]
related: ["bug-1785"]
fix_commits: ["6ecd418d"]
gitea_issue: 358
gitea_synced_status: "fixed"
gitea_synced_hash: "0d19e8b066b2"
---

# bug-1933: xce_scheduler limit plugin resolves hosts: scopes against project groups (host-group limits ignored)

## Description
**Observed:**
The scheduler's limit plugin built every limit with the host-group and
project-group managers swapped. A limit scoped to a host group never
matched that group's hosts; a limit scoped to projects resolved its member
names against the host groups. The new regression test, before the fix:
```
../scheduler/testsuite/test_limit_plugin.c:491:test_limit_scopes_resolve_against_own_group_kind:FAIL: Expected 1 Was 0
```
(host group `hg1` = {`hostA`}; a limit with `hosts: [hg1]` did not match
host `hostA`.)

**Expected:** a limit's `hosts:` members resolve against the host groups
(`hosts: [hg1]` matches every host in `hg1`), and its `projects:` members
resolve against the project groups (a project name never matches a host
group).
**Impact:** wrong result, silent. Every host limit that names a host group
applies to no host (only to a host literally named like the group), so the
limit is never enforced. A project limit whose member name equals a host
group's name matches the projects named like that group's hosts instead of
the project itself. Limits naming plain host or project names, and limits
without host/project scopes, are unaffected. In addition, the groups a
limit builds for its own scopes were registered in the wrong manager
(`<limit>-pg-group` in the host groups, `<limit>-hg-group` in the project
groups).
**Found by:** review, during `/kiro-spec-requirements project-config`
(2026-10-10, codebase survey of project-scoped limits).

## 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), `ASAN_OPTIONS=detect_leaks=0`
- Code: scheduler-framework @ 25cdbc79-dirty
- Deployment: n/a (unit test of the scheduler limit plugin); the defect is in
  code shared by the live scheduler and `xce_scheduler --sim`.

## Reproduction
1. `cd src && nix develop . --command meson compile -C xce.build sched_limit_plugin_test`
2. `ASAN_OPTIONS=detect_leaks=0 ./xce.build/scheduler/testsuite/sched_limit_plugin_test`
3. Test `test_limit_scopes_resolve_against_own_group_kind`
   (`src/scheduler/testsuite/test_limit_plugin.c`): loads host group
   `hg1` = {`hostA`}, configures limit `host_scoped` with `hosts: [hg1]` and
   limit `project_scoped` with `projects: [hg1]`, then checks
   `match_limit()` for host `hostA`/`hostB` and project `hostA`/`hg1`.
- Frequency: deterministic
- Evidence: the test above; no logs kept.

## Root cause
`build_limit()` (`src/lib/xcelimit.c:292`) takes its group managers as
`(ugmgr, qgmgr, hgmgr, pgmgr)`, but `limit_seed_config_impl()`
(`src/scheduler/src/plugins/limit.c:77`) passed
`(core->ugmgr, core->qgmgr, core->pgmgr, core->hgmgr)`. `build_consumer()`
therefore built the HOST consumer with the project-group manager and the
PROJECT consumer with the host-group manager. `make_g_member()`
(`src/lib/group.c`) treats a member name as a nested group only if the
manager it is given knows that group, so `hg1` became a literal host name
(the project-group manager is empty) and a project member named like a host
group became that host group. Since `ecf1916d` (2026-01-12, "support
limit"), the first version of the plugin call; carried through `7c229284`
and `487e7b94`. Scope: `limit.c:77` is the only production caller of
`build_limit()` (checked with `grep -rn "build_limit("`); the lib tests
(`src/lib/testsuite/test_limit.c`) pass the managers in the right order.

## Fix
`src/scheduler/src/plugins/limit.c`: pass `(core->hgmgr), (core->pgmgr)` in
the order `build_limit()` declares, so each scope resolves against its own
kind of group. No wire, WAL, snapshot or config change. The project-group
manager is still never loaded from config (projects have no config yet);
that is `project-config` scope (Requirement 6.7).
`src/scheduler/testsuite/test_limit_plugin.c`: new regression test; `main()`
now initializes the interned-string table (`xstring_table_init()`), which
group names need and which no earlier test in this binary exercised.

## Verification
- Test: `test_limit_scopes_resolve_against_own_group_kind`
  (`src/scheduler/testsuite/test_limit_plugin.c`): RED before the fix
  (`Expected 1 Was 0` at line 491, `hosts: [hg1]` not matching `hostA`),
  GREEN after (6/6 in `sched_limit_plugin_test`).
- Suites: scheduler suite 119/119 OK, libxce tests 2/2 OK, asan
  (`xce.build`), 2026-10-10.
- Live: n/a: the change is one argument order in config-time limit
  construction, fully covered by the unit test; no live limit run.

## References
- Found during: `.kiro/specs/project-config/requirements.md` (Requirement 6.7)
- Introduced: `ecf1916d`