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actors.t27: significant children end a team when its lead ends #7003
Description
Problem
A one_for_all team whose lead task finished keeps its helpers alive until something else stops them.
Evidence
OTP 24 supervisors mark children significant and take auto_shutdown (never, any_significant, all_significant) (https://www.erlang.org/doc/apps/stdlib/supervisor.html).
Proposal
A significant flag on a child spec plus the three auto_shutdown modes, with OTP's restriction kept: only transient or temporary children may be significant. The Queen's one_for_one domains have no lead, so the default stays never and the constant says why.
Part of epic #6971 (BEAM-style actors under the Queen, specs/queen/actors.t27). Source: the competitor table in the epic's comments.
Acceptance
- the rule is a
pub fnor constant in specs/queen/actors.t27 (or control.t27 where named), called by a test with runtime asserts (t27c test-report: 0 vacuous); - parse, typecheck, gen-rust, gen-c, gen-verilog exit 0;
t27c gen+zig testpass; tri mutate spec --fn NAME(tri mutate spec: guard and operator mutants of a .t27 spec, run through t27c gen + zig test #6993) on each new function: every survivor is killed by a new assert or named as equivalent in the commit body.
Activity
gHashTag commentedon Oct 6, 2026
Local commit c550b1e55 on
claude/queen-actors-next2(stacked on #7001; it lands in one PR after #7001 merges).One rule beyond the proposal, taken from OTP's own warning on the supervisor page: a supervisor with
auto_shutdownmust not be a permanent child of its parent, or the parent restarts it at once and the shutdown it chose is undone (and each restart counts toward the parent's intensity). It isauto_shutdown_sticks(sup_rtype). It gives the Queen's default a second reason besides "no lead child": the domain supervisors are permanent children of the root, so any mode butneverwould be undone, and a test asserts that.Mutation:
tri mutate spec --fn8/8, 10/10 and 2/2 killed on the three new functions. A hand mutant of the constants found one real gap (AUTO_ALL_SIGNIFICANT2 -> 3 let the range guard admit a non-mode). It is closed by an invariant pinning the modes to 0, 1, 2.spec(queen): actors jitter, significant children, call cycle, max chi…
feat(t27b): std.mem.eql/indexOf on byte slices and byte-array pointers (
fix(codegen): gen-rust enum order and gen-zig float-call cast (#6941) (…