`ensure_server` reused any live server whose `language_id` matched,
regardless of project root — its own comment documented this as a known
post-v0.1 limitation. For project-model-strict servers that is a
correctness failure, not a rough edge: `lake serve` is bound to one Lake
package, rust-analyzer and gopls to one workspace, so the second project
a user opens gets a server that cannot resolve its imports.
Server affinity is now keyed on the project root, with one rule that
keeps the change from regressing every other language:
The affinity key is the root only when a root was actually FOUND.
`project_root_for` never returns nil for a file that has a path — its
last resort is the file's own directory — so a naive `(language_id,
root)` key would give every directory of loose scratch files its own
server, for every language: two stray .py files in different directories
would spawn two pyrights where today they share one. It now returns
`root, source` with source one of "config" / "detected" / "fallback",
and only the first two become an affinity key.
Matching is on the spawned spec's `root_uri`, nil matching nil, so the
fallback spawn passes `root_uri = nil` for the key and the stored spec to
agree. `cwd` still carries the directory, and `build_initialize`
(src/lsp.rs) derives the identical `rootUri` from `cwd` when the field is
None — using a percent-encoder with the same allowed set as Lua's
`file_uri_for`. The initialize payload for that case is therefore
byte-identical to before; only what the reuse loop matches on changes.
`build_initialize` is the only reader of `spec.root_uri` in the tree.
Two consequences, both deliberate and both asserted rather than
discovered:
- A server hand-spawned from init.lua with only `cwd` set also reads
back nil, so a root-bearing attach will not adopt it. We cannot know
which root it was meant to serve, and guessing wrongly routes a
project's files to the wrong server.
- Opening files across N project roots spawns N servers. rust-analyzer
has the same property and no editor caps it by default; `pmacs.lsp.stop`
is the manual escape and an LRU reaping policy stays deferred.
`config[language].root` may now be a `function(path) -> string|nil` as
well as a string, for languages whose root rule the shared marker walk
cannot express — an innermost-wins walk cannot find an *outermost*
marker. A resolver returning nil declines and falls through to the marker
walk. Results are memoized per directory because hoisting the root
computation above the reuse loop puts it on every attach rather than
every spawn; the memo is keyed weakly by the resolver function itself, so
replacing `config[lang].root` cannot serve a root the old one computed.
`pmacs.lsp.list()` rows gain `root_uri` and `cwd`. `root_uri` is the spec
field verbatim, deliberately not the URI the server was initialized with.
No protocol change. No Lean content: this is the shared affinity function
for every LSP language, so it ships as its own PR and is exercised
through rust, python, go and typescript against `pmacs_fake_lsp`.
tests/lsp_multi_root_acceptance.rs covers acceptance 13-21. Every fixture
sets `pmacs.project.set_search_boundary` at its own tempdir root:
without it the marker walk climbs to the filesystem root, and a stray
`.git` above the temp directory would turn the markerless cases into
detected ones — the assertions would still pass while testing nothing.
Refs docs/lean4-mode-framing.md Q#LN15, acceptance 13-21.
Levi Neuwirth
1ae5963e9d