resource-limits.json and topology.json were read with parse errors
folded into an empty map, and written in place with std::fs::write. One
truncated resource-limits.json followed by a single set_limits call
rewrote the file with only that agent's entry, erasing every other
agent's CPU and memory overrides without a log line. topology.json had
the same shape: reconcile rebuilt it from the live set, losing pending
(provisioned, never spawned) names.
- agent_config::read_map / write_map are generic over the stored type.
tool-groups and capabilities behave as before.
- resource_limits::read / effective return an error for an existing but
unreadable file; a missing file is still the empty map. set_limits
fails without writing on such a file, and writes atomically.
- topology: reconcile fails without writing on an unreadable file and
writes atomically. all_agents logs the error and returns no agents,
so a ManageRootAgent holder starts without cross-agent mounts.
Read-path behaviour on an unreadable resource-limits.json, per caller:
- write_dropins (every spawn / swap / WriteDropin): logs the error and
keeps the limits drop-in already under /run; the agent still starts.
With no drop-in yet (first start since boot) it writes the hive
defaults, because no drop-in means an uncapped container.
- render_flake: propagates, so sync_agents (and spawn/rebuild/destroy
jobs) fail. An empty map would give tighter-capped agents the hive
memoryMaxBytes.
- container_view::build_all: logs the error each scan and renders the
rows at the hive defaults (no ContainerView wire change).
- set_resource_limits reply: propagates.
Closes#4731