Journey Stage 1a built `pmacs.window.commit_to` for the continuation
boundary --- "the listing settles a tick or more later, and by then the
ambient frontend, selected window, and active buffer may all name
something else" --- but nothing outside the `path.open-directory`
dispatch could mint a destination to hand it. Every other async Lua
continuation therefore resolved its target from ambient state a tick
after the request, which is PR #227's P1a finding: run `git.status` in
frontend A, let B become active, and A's panel opens in B.
This is the prerequisite lane #227 blocks on
(`docs/destination-capture-framing.md`, revision 5). No adopter here:
git's adoption is #227's work, since a prerequisite that converts its
own first consumer cannot be reviewed separately from it.
Three parts.
**`pmacs.window.capture_destination()`** returns the same
nonconstructible userdata for the current frontend. No arguments, and
that is load-bearing rather than minimal (Q#DC-1): a Lua-supplied
frontend id would reintroduce exactly the fabrication hole the userdata
design closes. Profile-blind for the same kind of reason (Q#DC-4) ---
capture freezes what is true now, and what a commit depends on is
declared later, at the commit.
**`DirectoryDestination` -> `ViewDestination`**, with the Lua userdata
and the capture renamed to match. The captured triple was already
generic; only its name and its capture site were not. The document pair
is now `Option`, set and cleared together, so a frontend with no live
document window still captures rather than returning nothing and
sending the caller back to the ambient state this exists to replace.
**`commit_to(dest, body [, profile])`** (Q#DC-2/Q#DC-5), a closed set of
two. The document profile keeps all four preflight checks. The panel
profile keeps only the first --- the requesting frontend still has a
layout --- because a panel result does not occupy the captured document
window, does not replace its buffer, and does not need it to exist, so
each of the other three would refuse for a reason unrelated to what the
continuation does. Omitting the profile means `"document"`, which is
what makes the preservation promise contractual rather than careful:
every existing two-argument caller keeps all four checks by definition
of the signature.
The profile argument is typed `mlua::Value`, NOT `Option<String>`, so
its error is REACHABLE: with the narrower type mlua rejects a number or
a table during argument conversion, before the closure body runs, and
the message naming the accepted values never appears. That is the same
trap the `dest` argument documents one position to its left. `nil` and
absence are the same answer; anything else is refused by one message
that names both accepted values.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016bqGA6s9tTUFzYpbeW3tai
Levi Neuwirth
9fee5618ee