Stage 3 step 2 (Q#S3-1). DEFAULT-PRESERVING WITH ONE INTENTIONAL
NORMALIZATION — not "behaviour-preserving", which would be too broad a
claim. Every adopter keeps its current default, and the full serialized
suite is 3447 passed / 0 failed with ZERO suites differing from the
pre-change baseline. But invalid-input behaviour DID move, deliberately,
and that is pinned rather than asserted in prose.
Before this, FOUR adopters validated the same three-value vocabulary in
four places: Rust for the terminal, and hand-written Lua copies in
listview.lua, compile.lua and dired.lua, each carrying its own copy of
the error string. `parse_adopter_placement` read like the shared parser
its doc comment implied but had exactly one caller. Four copies of one
rule is how the next adopter gets it subtly wrong, and the next adopter
is DAP.
`resolve_adopter_display(operation, raw, default)` now owns exactly
three things: the vocabulary, the error text, and the default policy.
Reachable from Lua as the internal seam `pmacs.window._resolve_display`.
THE DEFAULT IS A PARAMETER, NOT A CONSTANT, and that is load-bearing
rather than stylistic. listview/compile/terminal will resolve omission
to the panel in step 3; DIRED MUST NOT, because
`pmacs.path.set_directory_handler` calls it with `{ dest = dest }` and
no `display` key at all — a flipped default would open `pmacs .` in a
bottom panel. Passing the default in makes dired's exemption visible at
its call site instead of hidden in a divergent copy.
TERMINAL'S `window` MUTUAL-EXCLUSION STAYS IN ITS OWN WRAPPER. Only the
terminal accepts a `window` id and only it must reject `window` combined
with `display = "panel"`. A helper pretending the four parsers were
identical would be its own defect.
THE NORMALIZATION, DECIDED AND PINNED. Terminal read
`get::<Option<String>>("display")?`, so a non-string value raised mlua's
TYPE error before reaching any custom message, while the Lua copies
stringified it into their own. Nothing pinned either behaviour — every
existing assertion passes an unknown STRING, which takes the same path
under both designs and therefore could not have caught a regression
here. The custom error wins because it names the legal vocabulary; the
value is rendered by TYPE ALONE (`unknown display (integer)`) so the
message cannot imply a string was passed.
Pinned at the terminal entry point in acc19 — the one adopter whose
behaviour changed — asserting the shared error AND that nothing is
created. The type SPELLING is deliberately not pinned: Lua 5.4 says
`integer` where LuaJIT has no integer subtype, so asserting either
literal would pass on one CI flavor and fail on the other. Verified
46/46 under both.
COMPILE NEEDED AN EXPLICIT OMISSION CAPTURE, and finding that out is
what this step is for. The resolver collapses omission into its default,
but compile's recompile gate distinguishes them: it fires on OMISSION
only, never on an explicit `display = "current"`, which is the
documented opt-out and must reach the raw switch even when the previous
run was panel-placed. Resolving first and testing `== "current"`
afterwards would have silently merged the two and broken the opt-out
with every test still green. `display_omitted` is captured before the
resolver call and the gate keys on it.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Levi Neuwirth
41d37fcbcb