Module project 

Which project a path belongs to (slice PR.1).

Design: project-resolution.md.

A project is a pure function of a path with a cache in front of it. There is no “current project” here — no mutable session state to persist, invalidate, or fall out of sync. Multiple projects therefore co-exist by construction: buffers from three checkouts each answer with their own, and an action in one cannot re-root another because there is no shared cell for it to write.

Why for_path is total

ProjectResolver::for_path returns Project, never Option<Project>. That signature is the design. lattice-magit’s workdir.rs records what the alternative produced: eleven hand-written copies of the same discovery, three of them passing a file where a directory was required and silently defaulting — one of which meant gutter diff signs had never worked, for any file, since they landed. Every caller writing its own .unwrap_or_else(cwd) is every caller getting a chance to write it wrong. A consumer that cannot express “no project” cannot get “no project” wrong.

Why no gix

.git is the first marker, and a marker walk is sufficient: a .git entry marks a worktree root whether it is a directory (ordinary clone) or a file (submodule, git worktree add). The walk and gix::discover therefore agree in every case a user will meet; they diverge only under GIT_WORK_TREE / GIT_DIR, core.worktree, and ceiling directories.

That divergence is accepted deliberately. Only three crates depend on lattice-vcs today, and every crate depends on this one — routing resolution through gix would pull a heavy compile-time and binary-size dependency behind lattice-core and therefore into the whole workspace, to walk up a directory tree. magit is the one consumer for which the distinction is load-bearing, and it keeps its own gix discovery because it needs the Repository object anyway.

ProjectResolver is a trait, so this is reversible: a gix-backed impl can be registered later without any consumer changing.

Structs

ExcerptSource

Where a composed line came from: the source document, its file, and the 0-based line within it.

MarkerResolver

The built-in ProjectResolver: walk up for a marker, else pwd.

Project

The project a path belongs to.

Enums

ProjectKind

How a Project’s root was decided — for :project-root, for diagnostics, and for the rare consumer that legitimately cares (magit wants a VCS root specifically; a terminal does not).

Constants

DEFAULT_ROOT_MARKERS

The markers a project root is recognised by, in priority order within a single directory.

Traits

ExcerptSourceResolver

Answers where a line of a composed (multibuffer) buffer came from.

ProjectResolver

Resolves paths to projects.

ViewArgsResolver

What arguments a provider view is currently showing (slice OA.27).

Functions

root_from_cwd

The project root containing the process’s working directory, over the default markers.

Type Aliases

ExcerptSourceResolverHandle

Shared handle to an ExcerptSourceResolver.

ProjectResolverHandle

Per the ServiceRegistry Arc/TypeId convention: register and look up under this exact alias.

ViewArgsResolverHandle

Shared handle to a ViewArgsResolver.