Arc 8 Stage 3a (framing Q#LN9, Q#LN20). No Lean content: this changes
the event drain every LSP language runs through, and is split from the
Lean server work for the reason Stage 2 was.
**The seams.** `handle_server_requests` handled five `request` methods
and `initialized`, dropping every `notification` and `response` on the
floor. Dropping responses made `pmacs.lsp.send_request` a write-only API
from Lua — the reply was drained and discarded, so nothing outside
Rust's typed stores could consume one. Two new arms route to
`pmacs.lsp.on_notification(method, fn)` (persistent, method-keyed) and
`pmacs.lsp.on_response(sid, request_id, fn)` (one-shot). Both extend the
existing loop rather than opening a second `events_take` caller, which
would steal events from it.
A one-shot is removed **before** invocation, so a raising handler cannot
be re-entered. Every subscriber is `pcall`ed and a raise reports through
`pmacs.editor.set_status` per COHERENCE §1.2 — not `pmacs.error`, which
is defined nowhere in production. The notification list's length is
captured before the walk so a subscriber registering another cannot
extend the list being iterated.
**The purge is driven off `pmacs.lsp.list()`, not off a death event.**
The framing said acceptance 34's second edge was a killed buffer. That
was wrong, and scouting the implementation is what caught it: pmacs
fires exactly five hooks (`buffer.after-edit`, `buffer.after-load`,
`buffer.after-switch`, `frontend.detached`, `process.after-tick`) and
there is no buffer-kill hook at all, so `lsp.lua` never tears an
attachment down and the drain keeps reaching that server. No leak there.
The real leak is a different path with the same root cause. The drain
builds its sid list from `attachments`, and `attach_buffer` drops a sid
from that table the moment `server_is_live` reports false — rebuilding
against a fresh server. So the `crashed` / `stopped` event that should
trigger the purge is precisely the one most likely to go undrained. A
purge wired to that event leaks exactly when it matters.
`pmacs.lsp.list()` enumerates the manager directly and is unaffected by
attachment bookkeeping, so the purge polls it after each drain: a sid
that is absent, terminal, or running a **new generation** settles its
pending one-shots with an error. The generation check uses the `attempt`
field, because a crash-then-restart reuses the sid — without it a
one-shot would sit waiting on a reply the dead generation owed.
**`pmacs.fs.canonicalize`** (Q#LN20) is the one synchronous function on
`pmacs.fs`, and synchronous is the point: its consumer is a
function-valued `config.root` called from `ensure_server` <-
`attach_buffer` <- `buffer.after-load`, where there is no coroutine and
`pmacs.fs.stat`'s awaitable handle is unusable. It is installed from
`install_async` rather than `install_project` purely for load order —
`make_workspace` runs after `fs.lua` is evaluated, so a canonicalizer
placed there reads nil.
Acceptance: `tests/lsp_dispatch_seams_acceptance.rs`, 14 tests, driven
against `pmacs_fake_lsp` through rust so nothing needs a toolchain.
Dispatch integrity is exercised at real co-occurrence — the fake server
writes `workspace/applyEdit` and the `executeCommand` reply back to
back, so both land in one `events_take` batch. 34b asserts affinity
survives a symlinked open and is paired with its own falsification: the
same resolver minus the canonicalize call spawns two servers, so the
positive case cannot be vacuous.
Levi Neuwirth
12236b265d