fix(scheduler): resolve limit host and project scopes against their own groups (bug-1933)

The limit plugin called build_limit() with the host-group and
project-group managers swapped, so a limit's hosts: members were looked up
among the project groups (a host-group name became a literal host name and
the limit never applied) and its projects: members among the host groups.
Pass them in the order build_limit() declares.

New test test_limit_scopes_resolve_against_own_group_kind; the test's
main() now initializes the interned-string table that group names need.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

.wolf/bugs/bug-1933.md

@@ -0,0 +1,104 @@
+---
+id: "bug-1933"
+status: "open"
+status_updated: "2026-10-10"
+status_note: "newly logged"
+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"]
+---
+
+# 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`