`latex_within_boundary` answered a question about path COMPONENTS with
string arithmetic:
dir:sub(1, #boundary + 1) == boundary .. "/"
With a `/` boundary the needle is `"//"`, which no canonical path
begins with. Every ancestor was therefore judged out of bounds, the
marker walk never examined a single directory, and each chapter of a
thesis got its own root — two texlab processes for one document tree.
The lane's headline behaviour, silently off, with all fourteen shipped
tests still green because every one of them clamps the boundary to its
own tempdir.
Fixed by comparing segments rather than characters, so the root is a
boundary with zero segments — containing everything by construction
instead of by a special case, and tolerating a trailing separator for
free. The same root-is-special trap sat at two other points on the same
path and is closed with it:
* `latex_parent_of` returned nil for a top-level directory, making `/`
the one directory the walk could never examine — the identical bug
from the far end. It now yields `/`, matching `walk_for_marker`'s
`Path::ancestors` on the Rust side, and still terminates because `/`
has no component to strip.
* `latex_root_for` sliced `/paper.tex` to an EMPTY directory, which
canonicalizes to nothing and made the resolver DECLINE — and a
decline is the one path that falls through to `pmacs.project.detect`,
whose walk includes `.git`. A document at the filesystem root now
roots at `/`.
* `latex_marker_in`'s join is guarded for `dir == "/"`, which this
change makes reachable for the first time; the naive form produces
`//name`, the one spelling POSIX leaves implementation-defined.
Two new pins plus a strengthened one, 16 tests:
* `two_chapters_share_one_server_under_a_root_search_boundary` — the
defect end to end through ATTACH, not on the predicate, because the
symptom is two servers rather than a wrong string. Restoring the old
comparison fails exactly this test, with the two-server output.
* `latex_root_walk_stops_at_the_search_boundary` now asserts BOTH
directions. "Stops at the boundary" is also satisfied by a walk that
never runs — which is precisely what a `/` boundary produced — so the
hermeticity property (R8's shape: a stray `latexmkrc` above the
tempdir must stay invisible) is now paired with the walk still
climbing to, and examining, the boundary directory itself.
* `latex_root_for_a_document_at_the_filesystem_root_is_the_root`.
Also corrects `docs/active-work.md`: §3 no longer awaits a revision 3 —
`b5eaf27` IS revision 3 — and the lane entry now records that boundary
handling has been this resolver's interesting part twice, so a reader
weighing whether to trust it knows where to look first.
Gates: ALL GREEN via `./scripts/gate --acceptance lsp_latex_acceptance`.
`/tmp` on this machine is a near-full tmpfs and three grep tests fail
there with `QuotaExceeded`; the green run used
`TMPDIR=/home/jeans/build/pmacs-gate-tmp/lsp-latex`.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016bqGA6s9tTUFzYpbeW3tai
Framing: `docs/lsp-language-coverage-framing.md` (revision 2, §3 and
§6). One `pmacs.lsp.config.latex` entry — command `texlab`, args none,
a function-valued `root`, and deliberately nothing else.
STEP ZERO: the §3 caveat, discharged by observation.
Revision 2 marked marker 1 (`.texlabroot`) UNVERIFIED and blocking:
only texlab's version and CLI had been checked, and the CLI exposes
just `run` / `inverse-search`. Driving a minimal LSP client against
`texlab run` by hand, plus reading texlab's own source at the exact
installed tag, settles it — and corrects the premise underneath it.
`.texlabroot` IS a real marker. `crates/distro/src/language.rs` at
v5.25.1 maps `.texlabroot`/`texlabroot` -> Root, `Tectonic.toml` ->
Tectonic, `.latexmkrc`/`latexmkrc` -> Latexmkrc, and
`ProjectRoot::walk_and_find` (`crates/base-db/src/deps/root.rs`) walks
ancestors testing all three, innermost wins. So the shipped marker set
is texlab's own rather than a plausible-looking guess, and marker 1
stays.
But texlab CANNOT apply that walk to rescue a root pmacs gets wrong.
Each arm of `walk_and_find` searches `workspace.iter()` — documents
already loaded — and the workspace is built from the folders the CLIENT
supplies. Live sessions confirm it: with `rootUri` at a `chapters/`
subdirectory, no marker above it (`.texlabroot` included) widened
texlab's view, and its dependency graph never reached the parent
document; with `rootUri` at the marker directory the parent resolved,
marker present or not. texlab honours the root it is handed and never
corrects a too-narrow one.
That inverts the significance of the resolver rather than weakening it:
whatever `config.latex.root` returns *is* the project scope. It is the
whole value of the lane, not a nicety.
Also observed, because the entry depends on it: bare `texlab` serves
LSP over stdio — `initialize` returns `TexLab 5.25.1` with no
subcommand — so `args = {}` is right and `run` is not needed.
WHY `.git` IS EXCLUDED, AND WHY THAT IS NOT AN OMISSION.
texlab wants the document root; a thesis inside a monorepo must not get
the monorepo. The subtlety is that leaving `.git` out of the marker
list does not achieve this on its own. `project_root_for` falls through
to `pmacs.project.detect` when a resolver returns nil, and that walk
does include `.git` — so a resolver that declined on a markerless file
would hand texlab the repository root by the back door. The resolver
therefore never declines for a file that has a directory: no marker
means the file's own directory, which is also framing marker 4. The
acceptance pins this end to end through attach, not just on the
resolver's return, and asserts in the same fixture that the shared
detector really would have answered the repository root.
NO FILETYPE MAPPINGS, per revision 2 §2 — verified, not inherited.
`src/syntax.rs` already declares `name: "latex"` with `extensions:
["tex", "latex", "sty", "cls"]`, and grammar-extension detection sits
ahead of the LSP filetype map in `detect_buffer_language`
(`syntax.lua`). A `.tex` buffer already resolves to `latex`. The suite
asserts both halves — the extensions resolve, and `pmacs.lsp.filetypes`
is empty for them — so a later "helpful" addition cannot be mistaken
for the thing that made attach work.
Q#LX1: no `settings`, no `init_options`. Build-on-save and
forward-search are both opinionated and forward-search needs a
configured viewer.
Fixtures bound detection with `pmacs.project.set_search_boundary` and
assert the boundary took — R8's hazard is exactly this fixture's shape,
and one test pins the walk stopping at the boundary directly. Attach
fixtures use `pmacs_fake_lsp`, and the missing-server fixture an
asserted-absent path: texlab is installed on this machine, so relying
on either its presence or its absence would behave differently here and
in CI.
Verification: fourteen tests, one per §6 bullet plus the boundary and
decline cases. Seven mutations each fail the suite — resolver declining
on no marker (6 tests), no marker walk (4), a redundant `filetypes.tex`
(1), boundary ignored (1), `io.open` truthiness so a directory counts
as a marker (1), marker set narrowed (4), command renamed with
opinionated settings added (1).
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016bqGA6s9tTUFzYpbeW3tai
Levi Neuwirth