Module stack_relief 

Fresh-task stack relief for deep async construction chains.

At opt-level=0 LLVM performs no stack-slot coloring, so the poll function of a large async fn reserves a separate stack slot for every local in every branch. Deep construction chains (session runtime registration, agent build, mob machine commands) therefore carry enormous poll frames, and awaiting them inline stacks those frames beneath the caller’s own poll chain — e.g. an agent’s run loop → tool dispatch → mob spawn → child-session registration. That sum is what overflowed the 2 MiB production worker-stack budget asserted by tools_full_with_explicit_auth_binding_can_spawn_within_production_stack_budget.

relieve_caller_stack moves such a chain onto its own tokio task, so its frames start near the top of a fresh task poll rather than on top of the caller’s. It takes a future-maker rather than a future because tokio::spawn moves its argument by value: a large future would otherwise transit the caller’s stack (and the spawn call’s frame) at its full size. The maker closure is small (its captures), and the future it makes is materialized and boxed on the fresh task’s stack instead.

Functions

relieve_caller_stack

Runs the future produced by make_future on its own tokio task and awaits its completion, aborting the task if the caller is dropped first.