Migrates match_job_global_limit_()/limit_job_election()/
match_job_host_limit_() (plugins/limit.c) to read plugin->core (added
task 1.2) instead of deriving xce_scheduler_t* from plugin->sched,
which stays NULL for a plugin registered via plugin_register_core()
(simulation mode). Removes the dead ctx.sched write flagged during
task 2.1's review -- verified this ctx never has .sched read anywhere
downstream.
Fixes bug-1828 (found while writing this task's own TDD test for a
previously untested code path): match_job_host_limit_() had the same
key_find()-negative-rc-treated-as-fatal defect bug-1786 already fixed
in its global-limit sibling, but never applied here -- meaning
host-scoped resource limits were never actually enforced, in any
mode, until this fix (not merely a display gap; the limit's vres was
never added to obj->hlimits, so sched_fill_limit_requests() always
saw an empty list for it).
TDD: new tests drive the real hook-registered entry points against a
plugin_register_core()-registered plugin, asserting real usage
instances via limit_get_usage_instances() for both global and
host-scoped limits.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RLSNJhNoULvVcUhXEFafQC
Rongsong Shen
fc23ea8d31