`buffer.after-edit` fan-outs NEST — the typed-edit contract supports a
consumer calling `pmacs.hook.run`, and typed_edit.lua's header says so
in its second paragraph. A nested run re-enters every subscriber,
including the deferred expansion's, while the OUTER chain is still
walking its consumer list and pairing has not yet seen the terminator.
So a consumer registered at priority 75 — between the expander at 50
and pairing at 100 — that runs one nested fan-out made `\alp(` yield
`α(` again: the nested pass consumed the queued expansion and edited,
and outer pairing then resumed holding a record the replace had
invalidated. That is round 10's failure reached through the chain's
documented re-entrancy seam rather than through claiming, which is why
deferring alone did not close it.
Deferring work past a fan-out means owning WHICH fan-out it belongs to.
The chain's subscriber and this module's each run exactly once per
fan-out, in that order, so counting invocations of the first and
matching them off in the second identifies the nesting level. Only the
outermost pass expands; a nested one leaves the expansion queued. No
new seam in typed_edit.lua, which is merged Stage 4a substrate.
Both halves bite: removing the level check and never counting
invocations each fail the new acceptance 45n.
Also fixes a test comment that still described the span design round 10
discarded — it claimed the expansion replaces the span "INCLUDING the
terminator". The behaviour asserted was right; the explanation was
stale. Framing rev 11.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011LFvC4FQtux4y32KuevZ7B
Levi Neuwirth
0d7ec7e3a6