Tianyi Cui
743eb9ea09
The ACP bridge gives each session its own workspace (SessionHeader.cwd), and
dsh-tool-bash already resolves a bash workdir against it. But ctx.fs.resolve(path)
took no caller context and dsh-fs-local resolved every relative path against a
fixed config.cwd (process.cwd() at plugin load) — so in the ACP demo `write
foo.txt` and `bash cat foo.txt` hit different directories the moment an editor
opens any project other than the server's launch dir.
Thread the session cwd into resolution, mirroring dsh-tool-bash: widen
FileSystem.resolve to resolve(path, opts?: { cwd?: string }); dsh-fs-local bases
a relative path on opts.cwd ?? config.cwd (absolute paths ignore it); the
read/write/edit tools derive it via a shared sessionCwd(exec) helper
(exec.agent?.session.header.cwd). The provider stays free of dsh-agent/dsh-session
— the tool projects exec → cwd and hands over a plain string, per the
explicit-at-seams convention. Backward compatible (the arg is optional).
Tests: fs-local resolve(path,{cwd}) bases relative on the passed cwd / ignores it
for absolute; tool integration writes/reads/edits in a session cwd != config.cwd
and verifies the file on disk (proven to fail on the pre-fix no-cwd path). Fakes
that stood in a bare {session:{}} now carry a header so sessionCwd doesn't throw.
RFC in docs/rfc/implemented/architecture/2026-07-02-fs-per-session-cwd.md.
3.5 KiB
3.5 KiB
@deepseek-ai/dsh-fs-local
The local-filesystem implementation of the ctx.fs provider seam (@deepseek-ai/dsh-fs). Backs the six FileSystem primitives with the host filesystem; loading it as a plugin populates ctx.fs.
import { LocalFileSystem } from '@deepseek-ai/dsh-fs-local'
await ctx.plugin(LocalFileSystem, { cwd: process.cwd() })
// ctx.fs is now the local backend; load @deepseek-ai/dsh-fs-policy for the
// freshness policy gate and @deepseek-ai/dsh-tool-fs to expose read/write/edit.
Behavior
resolve(path, opts?)— a relativepathresolves againstopts.cwdwhen the caller supplies one (the model-facing tools pass the calling agent's session cwd — see the per-session cwd RFC), elseconfig.cwd(defaultprocess.cwd()); an absolutepathignores both. ThetargetKeyis the file'srealpath, so two input paths reaching the same file through symlinks share one identity, and writes/edits land on the link target (preserving the link). A not-yet-existing path uses the realpathed parent directory plus basename when the parent exists; only an unresolvable parent falls back to the absolute path.displayPathis the absolute (un-resolved) path.stat— returnsFsInfo(version=mtimeMs:size,typeoffile/directory/other, bytesize) orundefinedwhen the target is absent.readText/streamText— UTF-8 only.readTextreads the whole file;streamTextstreams it in chunks (cross-chunk decoding) so a huge file never has to be held whole in memory. Both reject invalid UTF-8 and NUL-byte binary samples (FS_NOT_TEXT) and non-regular targets. Thereadtool (@deepseek-ai/dsh-tool-fs) decides which to call by size and owns the line windowing.writeText— atomic: writes to a temp file opened exclusively (wx,0o600) inside a randomly-named private staging dir (0o700) next to the target, fsyncs, then renames over the target. An existing file's mode is preserved, while new files default to0o600. Theexpectedguard is OPTIONAL: omitting it unconditionally creates-or-overwrites;createIfAbsentcreates a missing target and rejects an existing one (FS_NOT_OBSERVED);replaceIfVersionreplaces only at the observed version (a missing target or mismatch isFS_STALE_VERSION).editText— atomic literal read-modify-write over the same primitive, serialized per target by a mutation lock. Theexpectedguard is OPTIONAL: when supplied it verifies the version BEFORE literal matching (a stale edit reportsFS_STALE_VERSION, neverFS_EDIT_NOT_FOUND/FS_AMBIGUOUS_EDITagainst newer content); omitting it edits the current content unconditionally. A missing target reportsFS_STALE_VERSIONeither way. LF-normalizes for matching, restores the file's dominant CRLF/LF style, and rejects emptyoldString/ zero matches (FS_EDIT_NOT_FOUND) or ambiguous multi-matches withoutreplace_all(FS_AMBIGUOUS_EDIT).
cwd is not a sandbox
config.cwd is a resolution default, not a containment boundary — absolute paths and .. escape it. Enforce containment with a stricter ctx.fs backend or a permission plugin on the tools/execute waterfall. See the filesystem capability-seam RFC's Risks section.
The raw I/O lives in src/fsio.ts (Cordis-free, independently unit-tested); src/index.ts is the thin service wiring.