Comparison

A · AGENTS.md · pnpm/pnpm B · AGENTS.md · pnpm/pnpm

What each file covers, counted
Dimension	Shared	Only in A	Only in B	Overlap
Sections	2	19	7	7%
Commands	7	25	0	22%
Section tags	5	4	1	50%

What each file covers

Sections

2 shared · 19 only in A · 7 only in B

− AGENTS.md (pacquet)
− The cardinal rule
− Modeling branded string types
− Follow the project guides
− Repo layout (inside `pnpm/`)
− Commands
− Tests
− No "tolerant" tests for missing tools
− Running tests narrowly
− One crate
− One test by name substring
− One integration test file
− Style
− Preserve existing method chains
− Code reuse (pacquet specifics)
− Errors and diagnostics
− Commit and PR hygiene
− Commit messages
− Things not to do
+ AGENTS.md (pnpr)
+ Relationship to pacquet
+ Layout
+ Code reuse
+ New registry-only crates
+ Dependencies
+ Style, tests, commits
What this project is
Comments

Commands

7 shared · 25 only in A · 0 only in B

− cargo nextest run -p pacquet-lockfile
− cargo nextest run -p pacquet-lockfile <name_substring>
− cargo nextest run -p pacquet-lockfile --test <file_stem>
− pnpm:<channel>
− pnpm login
− pnpm publish
− just ready
− cargo nextest run
− cargo clippy --locked --workspace --all-targets -- --deny warnings
− cargo check --locked --workspace --all-targets
− cargo fmt
− just cli -- <args>
− just registry-mock <args>
− just integrated-benchmark <args>
− cargo insta review
− cargo test
− just registry-mock launch
− git restore <file>
− git
− node
− npm
− pnpm/scripts/pre-push-rust.sh
− cargo clippy
− cargo-dylint
− git log --oneline
pnpm/
cargo
just
just test
just lint
just check
just fmt

Section tags

5 shared · 4 only in A · 1 only in B

− test
− types
− testing-strategy
− monorepo
+ dependencies
lint-format
code-style
architecture
git-pr
docs

Line diff

+83 added−403 removed32 unchanged7.4% identical

pnpm/pnpm · pnpm/AGENTS.md

@@ −1 @@

1# AGENTS.md (pacquet)

3Guidance for AI coding agents working in `pnpm/`.

5**Read [`../AGENTS.md`](../AGENTS.md) first.** It covers the conventions that apply across the whole monorepo — GitHub PR workflow, signing agent-authored content, conventional commit messages, code-reuse philosophy, "never ignore test failures," and the PR-conflict resolution script. This file specializes those rules for pacquet's Rust code and adds pacquet-only ones.

7## What this project is

9`pacquet` is the [pnpm](https://pnpm.io) CLI implemented in Rust. It is one of

10two parallel implementations of the same package manager — the other is the

11TypeScript pnpm CLI (the workspaces outside `pnpm/`). The two are kept

12behaviorally identical: the same commands, flags, defaults, error codes, file

13formats, lockfile shape, and directory layout. pacquet is not a downstream port

14that trails the TypeScript CLI; it is a source of truth in its own right, at

15near-complete feature parity, and the two stacks are developed together.

17## The cardinal rule

19**pacquet and the TypeScript pnpm CLI must stay behaviorally identical.**

20They are parallel implementations of one package manager, developed together at

21near-complete feature parity. Any user-visible change — a command, flag,

22default, error code or message, lockfile/manifest/state-file format, log

23emission parsed by `@pnpm/cli.default-reporter`, store layout, or hook

24semantic — must land in both stacks at the same time. The repo-wide statement

25of this obligation lives in

26[`../AGENTS.md`](../AGENTS.md#keep-pnpm-and-pacquet-in-sync); this section is the

27pacquet-side detail.

29Neither stack is downstream of the other. You are not "porting from" the

30TypeScript code: when you implement or change behavior in pacquet, make the

31equivalent change in the TypeScript workspaces in the same PR, and vice versa.

32If you genuinely can't (different expertise, scope too large, or the other

33stack hasn't grown the surrounding feature yet), ship your side and say so in

34the PR description so the matching commits can follow before it lands.

36Working rules:

381. **Keep the two implementations in agreement.** When you touch behavior in

39 pacquet, find the counterpart in the TypeScript workspaces — they live at

40 the repo root (`pnpm/` for the CLI entry, `pkg-manager/`, `resolving/`,

41 `lockfile/`, `store/`, `fetching/`, `config/`, `hooks/`, and so on; see the

42 [repo-structure section](../AGENTS.md#repository-structure)) — and change it

43 there too. The two must agree on logic, edge cases, config resolution, error

44 messages, and file/lockfile formats.

452. **Match observable behavior, not structure.** Structural similarity (similar

46 function decomposition and names) is a convenience for cross-referencing, not

47 a requirement. What must match is what a user or a downstream tool can

48 observe.

493. **Don't diverge unilaterally.** Do not add a feature, flag, or quirk to one

50 stack without the other, and do not "fix" a behavior in only one. A genuine

51 bug present in both is fixed in both.

524. **Log emissions are part of behavioral identity.** A function that fires

53 `pnpm:<channel>` events through the reporter must use the same call site,

54 payload, and ordering in both stacks so `@pnpm/cli.default-reporter` parses

55 pacquet's NDJSON the same way it parses the TypeScript CLI's. See

56 [Reporter / log events](./CODE_STYLE_GUIDE.md#reporter--log-events)

57 in the style guide for the convention (channel mapping, threading

58 `R: Reporter`, emit-site placement, recording-fake tests).

595. **Prefer real fixtures; reach for the dependency-injection seam

60 only when they can't cover the branch.** Most happy paths and

61 error paths should be tested with a `tempfile::TempDir`, the

62 mocked registry, or an integration test that spawns the actual

63 binary. Use the DI seam — a capability trait on the `Host`

64 provider, threaded as `Sys: <Bounds>` — only for branches a real

65 fixture can't reach portably: filesystem error kinds

66 (`PermissionDenied`, `ENOSPC`, …), deterministic time, shared

67 process-global state a test would otherwise mutate

68 (`env::set_var`, `set_current_dir`, the umask, …), or the

69 external-service happy paths in features like `pnpm login` (2FA)

70 and `pnpm publish` (OIDC / provenance) when those land. See

71 [Dependency injection for tests](./CODE_STYLE_GUIDE.md#dependency-injection-for-tests)

72 in the style guide for the gating rule, the names (`Sys`, `Host`,

73 `Fs*`, `Clock`, `EnvVar`, …), the eight principles, and the

74 `modules-yaml` worked example.

76If the intended behavior is unclear or looks wrong, stop and ask the user

77rather than guessing.

79## Modeling branded string types

81TypeScript pnpm leans on *branded* string types. A branded string is a

82plain string narrowed by a phantom property (for example,

83`type PkgName = string & { __brand: 'PkgName' }`), so the type system can

84track intent that the runtime cannot see. Some brands are stamped through

85a validating constructor. Others are minted with a bare `as` type assertion and

86have no runtime check at all. Both stacks must preserve that distinction,

87because it is part of the public contract pnpm exposes through manifest,

88lockfile, state, and config files. The TypeScript brand and the Rust newtype

89must agree on validation policy.

91Rules for a Rust newtype standing in for a branded string type ("the

92TypeScript side" below is its TypeScript counterpart):

941. **Declare a newtype wrapper.** Do not collapse the brand into a plain

95 `String` or `&str`. Give the type its own struct so misuse is a type

96 error in pacquet too.

972. **If upstream always validates before construction, validate too.**

98 When every brand site in pnpm runs through a checking factory, pacquet's

99 wrapper must construct only via `TryFrom<String>` and/or `FromStr`. Do

100 not provide an infallible public constructor that takes an arbitrary

101 string.

1023. **If upstream never validates, just brand for type-safety.** Some

103 upstream brands exist purely to keep the type system from confusing

104 one string slot with another. For example, a brand may exist to prevent

105 a `PkgId` from being passed where a `PkgName` is expected, even though

106 the value is never validated at runtime. In that case the Rust wrapper

107 should expose an infallible `From<String>` (and `From<&str>` when

108 convenient). The type-safety win is the whole point, and no validator

109 is needed.

1104. **If upstream occasionally constructs without validation, expose

111 `from_str_unchecked`.** When pnpm sometimes mints the brand via a bare

112 `as` assertion, skipping its validator, add a `from_str_unchecked` (or

113 similarly named) constructor on the Rust side so callers can opt into

114 the same unchecked path explicitly. Keep the validating constructor as

115 well. `from_str_unchecked` is the escape hatch, not the default.

1165. **Match upstream serde behavior.** If the branded type crosses a

117 JSON, YAML, or INI boundary (manifest files, lockfiles, state files,

118 config files, and similar), wire the wrapper into serde so the

119 validation policy survives serialization:

120 - `#[serde(try_from = "String")]` for deserialization, so

121 deserialized values go through the validator.

122 - `#[serde(into = "String")]` for serialization.

123 Use both when the type is round-tripped.

1246. **Derive simple conversions with `derive_more`.** When the conversion

125 impls implied by the rules above are mechanical (a one-liner that

126 wraps or unwraps the inner field), use `#[derive(derive_more::From)]`

127 and `#[derive(derive_more::Into)]` rather than handwriting an `impl`

128 block. Fall back to a manual `impl` only when the conversion needs

129 custom logic, such as validation or normalization. `derive_more` is

130 already a workspace dependency.

1317. **String-literal unions become `enum`s.** If upstream uses a string

132 literal type or a union of string literals (for example,

133 `'auto' | 'always' | 'never'`), model it as a Rust `enum`, not a

134 newtype wrapper. The set of valid values is closed, so encode that.

1358. **Template literal types are branded strings.** If upstream uses a

136 string template literal type (for example,

137 ``` `${string}@${string}` ```), treat it the same as a branded string

138 type. Use a newtype wrapper with the validation discipline from rules

139 2 through 5 above.

140

141## Follow the project guides

142

1431. Follow the contributing guide in [`CONTRIBUTING.md`](./CONTRIBUTING.md), and **ALWAYS** double-check before committing. It covers commit message format, writing style, setup, and the automated checks to run before committing.

1442. Follow the code style guide in [`CODE_STYLE_GUIDE.md`](./CODE_STYLE_GUIDE.md), and **ALWAYS** double-check before committing. It covers code-level conventions not enforced by tooling: imports, modules, naming, ownership and borrowing, parameter type selection, trait bounds, pattern matching, `pipe-trait`, error handling, test layout, logging during tests, and cloning of `Arc` and `Rc`.

145

146## Repo layout (inside `pnpm/`)

147

148- `crates/` — library and binary crates that make up pacquet.

149 - `cli`, `package-manager`, `package-manifest`, `lockfile`, `store-dir`,

150 `tarball`, `registry`, `network`, `npmrc`, `fs`, `executor`,

151 `diagnostics`, `testing-utils`.

152- `tasks/` — developer tooling: `integrated-benchmark`, `micro-benchmark`,

153 `registry-mock`.

154- `CONTRIBUTING.md` — commit-message format, writing style, setup, and the

155 automated checks to run before submitting. Read it before submitting code.

156- `CODE_STYLE_GUIDE.md` — manual code-style conventions beyond what `cargo

157 fmt`, `taplo`, and clippy enforce: imports, modules, naming, ownership

158 and borrowing, trait bounds, pattern matching, `pipe-trait`, error

159 handling, test layout, and `Arc`/`Rc` cloning. Read it before submitting

160 code.

161

162The Rust workspace (`Cargo.toml`, `Cargo.lock`, `rust-toolchain.toml`,

163`justfile`, `.cargo/`, `.taplo.toml`, etc.) lives at the **repo root**, not

164inside `pnpm/`. Run `cargo` and `just` from the repo root.

165

166## Commands

167

168Prefer `just` recipes when one fits; drop down to `cargo` / `taplo` / etc.

169directly when you need flags the recipe doesn't expose (e.g. filtering tests

170by crate or name — see below).

171

172- `just ready` — run the same checks CI runs (typos, fmt, check, test, lint).

173 Run this before declaring a task complete.

174- `just test` — `cargo nextest run`.

175- `just lint` — `cargo clippy --locked --workspace --all-targets -- --deny warnings`.

176- `just check` — `cargo check --locked --workspace --all-targets`.

177- `just fmt` — `cargo fmt` + `taplo format`.

178- `just cli -- <args>` — run the pacquet binary.

179- `just registry-mock <args>` — manage the mock registry used by tests.

180- `just integrated-benchmark <args>` — compare revisions or compare against

181 pnpm itself (see `CONTRIBUTING.md`).

182

183Warnings are errors (`--deny warnings` in lint). Do not silence them with

184`#[allow(...)]` unless there is a specific, justified reason.

185

186## Tests

187

188- Tests live alongside the code they exercise (standard Cargo layout) plus

189 integration tests under each crate's `tests/`. Shared pacquet fixtures live

190 under `crates/testing-utils/src/fixtures/`; registry package fixtures live

191 under `../pnpr/.fixtures/packages/`.

192- Snapshot tests use `insta`. When an intentional change alters a snapshot,

193 review the diff carefully, then accept with `cargo insta review`. Never

194 accept snapshot changes blindly.

195- Tests that need the mocked registry start `pnpr` through

196 `pacquet-testing-utils`; `cargo test` / `cargo nextest run` should not

197 require a separate `just registry-mock launch` step.

198- When a behavior change spans both stacks, keep their tests in sync — give

199 pacquet a Rust test for the same scenario the TypeScript stack covers (and

200 vice versa) whenever it translates. Matching test coverage is the easiest

201 way to prove behavioral parity.

202- The active test-porting plan lives in

203 [`plans/TEST_PORTING.md`](./plans/TEST_PORTING.md). It enumerates the

204 upstream TypeScript tests scheduled to be ported (with file paths and line

205 numbers) and the conventions expected of the ports — `known_failures`

206 modules, `pacquet_testing_utils::allow_known_failure!` at the

207 not-yet-implemented boundary, and the practice of temporarily breaking the

208 subject under test to verify the ported test actually catches the

209 regression. Consult it before adding ported tests, and update its

210 checkboxes as items land.

211- When temporarily breaking an implementation (to prove a test catches the

212 regression, or for any other experiment), revert with `git restore <file>`,

213 never by moving a saved backup copy into place. Cargo's freshness check is

214 mtime-based, and an mtime-preserving restore leaves the binary compiled

215 from the broken source looking fresh — later test runs then fail in

216 impossible-looking, "flaky" ways with nothing pointing at the stale

217 artifact. Details in the "Test the tests" section of

218 [`plans/TEST_PORTING.md`](./plans/TEST_PORTING.md). If test outcomes ever

219 flip with no code change, `touch` the implementation file and rerun before

220 debugging anything else.

221

222### No "tolerant" tests for missing tools

223

224Tests must not be tolerant of a missing build / runtime environment by

225silently `return`-ing early when a tool isn't found. Patterns like:

226

227```rust

228fn skip_if_no_git() -> bool {

229 if std::process::Command::new("git").arg("--version").output().is_err() {

230 eprintln!("skipping: `git` not on PATH");

231 return true;

232 }

233 false

234}

235

236#[test]

237fn my_test() {

238 if skip_if_no_git() {

239 return;

240 }

241 // ...

242}

243```

244

245are forbidden. If the test needs a tool, just call into it and let the

246existing `.unwrap()` / `.expect(...)` panic when the tool is absent — a

247failing test in an under-provisioned environment is the correct signal.

248Tolerance defeats the purpose of testing: if the environment really

249doesn't have the required tools, that's the *environment's* fault and it

250needs to be fixed.

251

252This applies in particular to `git`, `node`, and `npm` — git is ubiquitous

253on developer machines, and Node.js is a documented prerequisite for

254building pnpm. There is no realistic environment in which pacquet's tests

255should run *and* these tools should be absent.

256

257The only marginally acceptable exception is platform-locked tools — APIs

258or binaries that exist on one OS but not another. Even then, prefer

259`#[cfg_attr(target_os = "windows", ignore = "...")]` (or the matching

260`#[cfg(unix)]` gate already used in this crate for `/bin/sh` shims) over a

261runtime probe-and-skip helper. The gate is visible to `cargo test` and

262shows up in the test report; a silent `return` does not.

263

264### Running tests narrowly

265

266Running the full suite is slow. While iterating, target what you're working

267on:

268

269```sh

270# One crate

271cargo nextest run -p pacquet-lockfile

272

273# One test by name substring

274cargo nextest run -p pacquet-lockfile <name_substring>

275

276# One integration test file

277cargo nextest run -p pacquet-lockfile --test <file_stem>

278```

279

280Run `just ready` (full suite) before handing the PR off.

281

282## Style

283

284`CODE_STYLE_GUIDE.md` is the source of truth. Highlights:

285

286- Choose owned vs. borrowed parameters to minimize copies; widen to the most

287 encompassing type (`&Path` over `&PathBuf`, `&str` over `&String`) when it

288 doesn't force extra copies.

289- Prefer `Arc::clone(&x)` / `Rc::clone(&x)` over `x.clone()` for reference-

290 counted types, so the cost is visible at the call site.

291- Follow the test-logging guidance in the style guide — log before non-

292 `assert_eq!` assertions, `dbg!` complex structures, skip logging for simple

293 scalar `assert_eq!`.

294- Follow [Rust API Guidelines](https://rust-lang.github.io/api-guidelines/naming.html)

295 for naming.

296- **No star imports inside module bodies.** Write `use super::{Foo, bar}`

297 instead of `use super::*;`, and the same for any other glob whose

298 target is a module you control. Two forms stay allowed: external-crate

299 preludes such as `use rayon::prelude::*;` and root-of-module

300 re-exports such as `pub use submodule::*;` in a `lib.rs`. See the

301 "No star imports" section in `CODE_STYLE_GUIDE.md`.

302

303### Comments

304

305Same baseline as [`../AGENTS.md`](../AGENTS.md#comments): write code that explains itself; comments are for the non-obvious *why*, not a translation of the *what*.

306

307Rust-specific additions:

308

309- **Doc comments (`///`, `//!`) are rustdoc-visible API documentation.** Use them for item contracts. Put implementation-only rationale in regular `//` comments.

310- **Tests are documentation. Do not duplicate them in prose.** If a behavioral scenario, edge case, failure mode, or worked example is already captured by a test (its name, its setup, its assertions), do not also narrate it in the doc comment on the implementation. The doc comment should state the contract once; the test demonstrates the behavior. The same applies in reverse: a test's own doc comment should not re-explain what the asserts already say, only the *why* if it is not obvious.

311- **`// SAFETY:`, `// TODO:`, and similar prefixes are the exception.** They signal hidden invariants or known follow-ups that a reader cannot recover from the code alone.

312

313Prefer renaming, restructuring, or extracting a helper over leaving a comment. Reach for prose only when the right names and types genuinely cannot carry the information.

314

315### Preserve existing method chains

316

317When editing existing code, do not break a method chain (including `pipe-trait`

318`.pipe(...)` chains) into intermediate `let` bindings unless you can justify

319the rewrite. Valid justifications include a chain that fails to compile after

320your edit, a borrow checker rejection, a meaningful performance win from

321splitting it up, or any other concrete reason the chain cannot stay as it is.

322Refactoring for style alone is not a justification when the task is something

323else. Keep the surrounding code shape intact and confine your edits to what

324the task asks for.

325

326When the change you need can fit inside the existing chain, keep it there.

327For example, swapping a `PathBuf::from` allocation for a `Path::new` borrow:

328

329```diff

330 output

331 .stdout

332 .pipe(String::from_utf8)

333 .expect("convert stdout to UTF-8")

334 .trim_end()

335- .pipe(PathBuf::from)

336+ .pipe(Path::new)

337 .parent()

338 .expect("parent of root manifest")

339 .to_path_buf()

340```

341

342Do not flatten the chain just because you happen to be editing nearby:

343

344```diff

345-output

346- .stdout

347- .pipe(String::from_utf8)

348- .expect("convert stdout to UTF-8")

349- .trim_end()

350- .pipe(PathBuf::from)

351- .parent()

352- .expect("parent of root manifest")

353- .to_path_buf()

354+let stdout = String::from_utf8(output.stdout).expect("convert stdout to UTF-8");

355+Path::new(stdout.trim_end()).parent().expect("parent of root manifest").to_path_buf()

356```

357

358If you do need to break a chain, state the justification in your reply, the

359commit message, or the PR description so a reviewer can confirm the rewrite

360was warranted. If the rewrite is purely stylistic, raise it with the user as

361its own change rather than including it in an unrelated edit.

362

363## Code reuse (pacquet specifics)

364

365The general "search before you write / extract shared code / prefer mature

366crates / keep deps at the right level" rules from

367[`../AGENTS.md`](../AGENTS.md#code-reuse-and-avoiding-duplication) apply.

368Pacquet-specific notes:

369

370- Shared helpers tend to live in `crates/fs`, `crates/testing-utils`, and

371 `crates/diagnostics` — check there first.

372- Check whether the workspace already depends on something suitable (see

373 `[workspace.dependencies]` in the root `Cargo.toml`) before adding a new

374 dependency.

375- **Keep dependencies at the right level.** Add a new dependency to the

376 specific crate that needs it, not to the workspace root or to a shared

377 crate unless multiple crates actually depend on it.

378

379## Errors and diagnostics

380

381User-facing errors go through `miette` via the `pacquet-diagnostics` crate.

382Match pnpm's error codes and messages where pnpm defines them — error codes

383are part of the public contract, not implementation detail. See

384<https://pnpm.io/errors> for the canonical list.

385

386## Commit and PR hygiene

387

388- Keep commits focused. A bug fix commit should not also refactor or

389 reformat unrelated code.

390- When a change has a counterpart in the TypeScript pnpm CLI, land both

391 together; if they must be split, cross-reference the matching PR so a

392 reviewer can confirm the two stacks stay in sync.

393- Run `just ready` before pushing.

394- The repo-wide husky `pre-push` hook runs `pnpm/scripts/pre-push-rust.sh`,

395 which checks `rustfmt`, `taplo`, `cargo clippy` (with `--all-targets -D

396 warnings`), `cargo doc` (with `RUSTDOCFLAGS=-D warnings`), and `cargo

397 dylint`. Make sure your environment

398 can run cargo (the hook needs it) before pushing; `cargo-dylint` is

399 detected at runtime and skipped with a warning if not installed.

400

401### Commit messages

402

403Conventional Commits applies (see

404[`../AGENTS.md`](../AGENTS.md#commit-messages) for the full type list). Use

405a scope that names the crate or area being touched, matching the existing

406history (`git log --oneline` for examples). Pacquet adds one type beyond the

407standard list:

408

409- `bench`: benchmark-only changes.

410

411Examples (from this repo's history):

412

413```

414fix(network): set explicit timeouts on default reqwest client

415feat(lockfile): support npm-alias dependencies in snapshots

416perf(store-dir): share one read-only StoreIndex across cache lookups

417```

418

419## Things not to do

420

421- Do not add a feature, flag, or behavior to one stack without making the

422 same change to the other. The two move together.

423- Do not change lockfile format, store layout, `.npmrc` semantics, or CLI

424 surface in only one stack — those are the shared contract and must change

425 in both at once.

426- A dependency that is already declared in `[workspace.dependencies]` in the

427 root `Cargo.toml` may be added to any crate that needs it.

428- Do not add a dependency that is not already declared in the workspace

429 without an explicit human request. If there is a clear benefit and

430 justification for pulling in a new third-party crate, ask the human to

431 approve it and to add it to `[workspace.dependencies]` rather than adding

432 it yourself. Consult `deny.toml` when evaluating candidates.

433- Do not introduce `unsafe` without a clear justification and review.

434- Do not disable lints, tests, or CI checks to make a PR green.

435

pnpm/pnpm · pnpr/AGENTS.md

@@ +1 @@

1# AGENTS.md (pnpr)

3Guidance for AI coding agents working in `pnpr/`.

5**Read [`../AGENTS.md`](../AGENTS.md) first.** It covers the monorepo-wide

6conventions: GitHub PR workflow, signing agent-authored content, conventional

7commit messages, code-reuse philosophy, and "never ignore test failures."

9## What this project is

11`pnpr/` is a pnpm-compatible npm registry server written in Rust —

12roughly the role [verdaccio](https://verdaccio.org/) plays in the JS

13ecosystem. It is a **sibling** of `pnpm/`, not part of it.

15The two Rust projects share the same Cargo workspace at the repo root so

16that the registry can depend directly on `pacquet-*` crates (tarball

17handling, integrity hashes, manifest parsing, network plumbing, etc.) and

18the `Cargo.lock` stays unified.

20## Relationship to pacquet

22- **`pnpm/`** is a *port* of the pnpm CLI. Its cardinal rule is

23 "match pnpm exactly" — see [`../pnpm/AGENTS.md`](../pnpm/AGENTS.md).

24- **`pnpr/`** has no pnpm-CLI counterpart to mirror. It is a new

25 server. Behavior here is designed, not ported.

27That means the "match upstream pnpm" discipline that governs `pnpm/`

28does **not** apply here. The registry can pick its own architecture,

29flags, and config format. It must still be compatible with the npm

30registry protocol that pnpm (and npm, yarn, etc.) clients speak.

32## Layout

34Mirrors `pnpm/`:

36```text

37pnpr/

38 AGENTS.md

39 crates/

40 pnpr/ -> package "pnpr"

41 Cargo.toml

42 README.md

43 src/

44 lib.rs -> library API

45 main.rs -> binary entry point (ships the `pnpr` binary)

46 # future sibling crates land here, see "New registry-only crates" below

47```

49The Rust workspace itself, `rust-toolchain.toml`, `justfile`, and

50`Cargo.lock` live at the **repo root** — run `cargo` and `just` from there.

51`pnpr/crates/*` is wired into the root workspace `members`.

53## Code reuse

55**Prefer existing `pacquet-*` crates over writing new code.** Before

56implementing anything non-trivial, check whether `pacquet-*` already

57solves it. Candidates worth checking first: `pacquet-tarball`,

58`pacquet-crypto-hash`, `pacquet-crypto-shasums-file`,

59`pacquet-package-manifest`, `pacquet-network`, `pacquet-registry`,

60`pacquet-fs`, `pacquet-diagnostics`. Add a `pacquet-*` crate the same

61way pacquet crates do: declare it in the root `[workspace.dependencies]`

62(already done for the pacquet crates) and use `{ workspace = true }`

63in this crate's `Cargo.toml`.

65If a piece of code currently inside `pnpm/` turns out to be genuinely

66shared between the two stacks and the `pacquet-` prefix becomes

67misleading, propose renaming/relocating it in a dedicated PR — not as a

68drive-by during feature work.

70### New registry-only crates

72When the registry needs its own crate (logic that isn't shared with the

73pnpm port and doesn't fit in `pnpm/`), put it under

74`pnpr/crates/<short-name>/` and name the package

75`pnpr-<short-name>` in its `Cargo.toml`. The

76`pnpr/crates/*` glob in the root workspace `members` picks it up

77automatically; just add the new crate to `[workspace.dependencies]` at

78the root with the `pnpr-` prefix so other crates can use

79`{ workspace = true }`.

81Use the `pnpr-` prefix exclusively for registry-only crates.

82Don't reach for `pacquet-` to name something new on the registry side.

84## Dependencies

86Same rule as pacquet: a dependency that is already declared in

87`[workspace.dependencies]` may be used by any crate that needs it.

88Adding a new third-party crate to the workspace requires an explicit

89human request (see [`../pnpm/AGENTS.md`](../pnpm/AGENTS.md#things-not-to-do)).

91## Style, tests, commits

93Follow the pacquet code-style guide

94([`../pnpm/CODE_STYLE_GUIDE.md`](../pnpm/CODE_STYLE_GUIDE.md)) and the

95pacquet contributing guide ([`../pnpm/CONTRIBUTING.md`](../pnpm/CONTRIBUTING.md))

96for Rust-level conventions — imports, naming, ownership, error handling,

97test layout. They are written for pacquet but apply to any Rust code in

98this workspace.

100### Comments

101

102Follow the repo-wide comment baseline in [`../AGENTS.md`](../AGENTS.md#comments) and the Rust-specific additions in [`../pnpm/AGENTS.md`](../pnpm/AGENTS.md#comments).

103

104Commit messages use Conventional Commits with `pnpr` as the scope

105(`feat(pnpr): ...`, `fix(pnpr): ...`).

106

107Run the same checks pacquet does before declaring work done:

108

109```sh

110just check # cargo check --locked --workspace --all-targets

111just test # cargo nextest run

112just lint # cargo clippy --workspace --all-targets -- --deny warnings

113just fmt # cargo fmt + taplo format

114```

115

@@ −1 +1 @@

1−# AGENTS.md (pacquet)

1+# AGENTS.md (pnpr)

3−Guidance for AI coding agents working in `pnpm/`.

3+Guidance for AI coding agents working in `pnpr/`.

5−**Read [`../AGENTS.md`](../AGENTS.md) first.** It covers the conventions that apply across the whole monorepo — GitHub PR workflow, signing agent-authored content, conventional commit messages, code-reuse philosophy, "never ignore test failures," and the PR-conflict resolution script. This file specializes those rules for pacquet's Rust code and adds pacquet-only ones.

5+**Read [`../AGENTS.md`](../AGENTS.md) first.** It covers the monorepo-wide

6+conventions: GitHub PR workflow, signing agent-authored content, conventional

7+commit messages, code-reuse philosophy, and "never ignore test failures."

79 ## What this project is

810

9−`pacquet` is the [pnpm](https://pnpm.io) CLI implemented in Rust. It is one of

10−two parallel implementations of the same package manager — the other is the

11−TypeScript pnpm CLI (the workspaces outside `pnpm/`). The two are kept

12−behaviorally identical: the same commands, flags, defaults, error codes, file

13−formats, lockfile shape, and directory layout. pacquet is not a downstream port

14−that trails the TypeScript CLI; it is a source of truth in its own right, at

15−near-complete feature parity, and the two stacks are developed together.

11+`pnpr/` is a pnpm-compatible npm registry server written in Rust —

12+roughly the role [verdaccio](https://verdaccio.org/) plays in the JS

13+ecosystem. It is a **sibling** of `pnpm/`, not part of it.

1614

17−## The cardinal rule

15+The two Rust projects share the same Cargo workspace at the repo root so

16+that the registry can depend directly on `pacquet-*` crates (tarball

17+handling, integrity hashes, manifest parsing, network plumbing, etc.) and

18+the `Cargo.lock` stays unified.

1819

19−**pacquet and the TypeScript pnpm CLI must stay behaviorally identical.**

20−They are parallel implementations of one package manager, developed together at

21−near-complete feature parity. Any user-visible change — a command, flag,

22−default, error code or message, lockfile/manifest/state-file format, log

23−emission parsed by `@pnpm/cli.default-reporter`, store layout, or hook

24−semantic — must land in both stacks at the same time. The repo-wide statement

25−of this obligation lives in

26−[`../AGENTS.md`](../AGENTS.md#keep-pnpm-and-pacquet-in-sync); this section is the

27−pacquet-side detail.

20+## Relationship to pacquet

2821

29−Neither stack is downstream of the other. You are not "porting from" the

30−TypeScript code: when you implement or change behavior in pacquet, make the

31−equivalent change in the TypeScript workspaces in the same PR, and vice versa.

32−If you genuinely can't (different expertise, scope too large, or the other

33−stack hasn't grown the surrounding feature yet), ship your side and say so in

34−the PR description so the matching commits can follow before it lands.

22+- **`pnpm/`** is a *port* of the pnpm CLI. Its cardinal rule is

23+ "match pnpm exactly" — see [`../pnpm/AGENTS.md`](../pnpm/AGENTS.md).

24+- **`pnpr/`** has no pnpm-CLI counterpart to mirror. It is a new

25+ server. Behavior here is designed, not ported.

3526

36−Working rules:

27+That means the "match upstream pnpm" discipline that governs `pnpm/`

28+does **not** apply here. The registry can pick its own architecture,

29+flags, and config format. It must still be compatible with the npm

30+registry protocol that pnpm (and npm, yarn, etc.) clients speak.

3731

38−1. **Keep the two implementations in agreement.** When you touch behavior in

39− pacquet, find the counterpart in the TypeScript workspaces — they live at

40− the repo root (`pnpm/` for the CLI entry, `pkg-manager/`, `resolving/`,

41− `lockfile/`, `store/`, `fetching/`, `config/`, `hooks/`, and so on; see the

42− [repo-structure section](../AGENTS.md#repository-structure)) — and change it

43− there too. The two must agree on logic, edge cases, config resolution, error

44− messages, and file/lockfile formats.

45−2. **Match observable behavior, not structure.** Structural similarity (similar

46− function decomposition and names) is a convenience for cross-referencing, not

47− a requirement. What must match is what a user or a downstream tool can

48− observe.

49−3. **Don't diverge unilaterally.** Do not add a feature, flag, or quirk to one

50− stack without the other, and do not "fix" a behavior in only one. A genuine

51− bug present in both is fixed in both.

52−4. **Log emissions are part of behavioral identity.** A function that fires

53− `pnpm:<channel>` events through the reporter must use the same call site,

54− payload, and ordering in both stacks so `@pnpm/cli.default-reporter` parses

55− pacquet's NDJSON the same way it parses the TypeScript CLI's. See

56− [Reporter / log events](./CODE_STYLE_GUIDE.md#reporter--log-events)

57− in the style guide for the convention (channel mapping, threading

58− `R: Reporter`, emit-site placement, recording-fake tests).

59−5. **Prefer real fixtures; reach for the dependency-injection seam

60− only when they can't cover the branch.** Most happy paths and

61− error paths should be tested with a `tempfile::TempDir`, the

62− mocked registry, or an integration test that spawns the actual

63− binary. Use the DI seam — a capability trait on the `Host`

64− provider, threaded as `Sys: <Bounds>` — only for branches a real

65− fixture can't reach portably: filesystem error kinds

66− (`PermissionDenied`, `ENOSPC`, …), deterministic time, shared

67− process-global state a test would otherwise mutate

68− (`env::set_var`, `set_current_dir`, the umask, …), or the

69− external-service happy paths in features like `pnpm login` (2FA)

70− and `pnpm publish` (OIDC / provenance) when those land. See

71− [Dependency injection for tests](./CODE_STYLE_GUIDE.md#dependency-injection-for-tests)

72− in the style guide for the gating rule, the names (`Sys`, `Host`,

73− `Fs*`, `Clock`, `EnvVar`, …), the eight principles, and the

74− `modules-yaml` worked example.

32+## Layout

7533

76−If the intended behavior is unclear or looks wrong, stop and ask the user

77−rather than guessing.

34+Mirrors `pnpm/`:

7835

79−## Modeling branded string types

80−

81−TypeScript pnpm leans on *branded* string types. A branded string is a

82−plain string narrowed by a phantom property (for example,

83−`type PkgName = string & { __brand: 'PkgName' }`), so the type system can

84−track intent that the runtime cannot see. Some brands are stamped through

85−a validating constructor. Others are minted with a bare `as` type assertion and

86−have no runtime check at all. Both stacks must preserve that distinction,

87−because it is part of the public contract pnpm exposes through manifest,

88−lockfile, state, and config files. The TypeScript brand and the Rust newtype

89−must agree on validation policy.

90−

91−Rules for a Rust newtype standing in for a branded string type ("the

92−TypeScript side" below is its TypeScript counterpart):

93−

94−1. **Declare a newtype wrapper.** Do not collapse the brand into a plain

95− `String` or `&str`. Give the type its own struct so misuse is a type

96− error in pacquet too.

97−2. **If upstream always validates before construction, validate too.**

98− When every brand site in pnpm runs through a checking factory, pacquet's

99− wrapper must construct only via `TryFrom<String>` and/or `FromStr`. Do

100− not provide an infallible public constructor that takes an arbitrary

101− string.

102−3. **If upstream never validates, just brand for type-safety.** Some

103− upstream brands exist purely to keep the type system from confusing

104− one string slot with another. For example, a brand may exist to prevent

105− a `PkgId` from being passed where a `PkgName` is expected, even though

106− the value is never validated at runtime. In that case the Rust wrapper

107− should expose an infallible `From<String>` (and `From<&str>` when

108− convenient). The type-safety win is the whole point, and no validator

109− is needed.

110−4. **If upstream occasionally constructs without validation, expose

111− `from_str_unchecked`.** When pnpm sometimes mints the brand via a bare

112− `as` assertion, skipping its validator, add a `from_str_unchecked` (or

113− similarly named) constructor on the Rust side so callers can opt into

114− the same unchecked path explicitly. Keep the validating constructor as

115− well. `from_str_unchecked` is the escape hatch, not the default.

116−5. **Match upstream serde behavior.** If the branded type crosses a

117− JSON, YAML, or INI boundary (manifest files, lockfiles, state files,

118− config files, and similar), wire the wrapper into serde so the

119− validation policy survives serialization:

120− - `#[serde(try_from = "String")]` for deserialization, so

121− deserialized values go through the validator.

122− - `#[serde(into = "String")]` for serialization.

123− Use both when the type is round-tripped.

124−6. **Derive simple conversions with `derive_more`.** When the conversion

125− impls implied by the rules above are mechanical (a one-liner that

126− wraps or unwraps the inner field), use `#[derive(derive_more::From)]`

127− and `#[derive(derive_more::Into)]` rather than handwriting an `impl`

128− block. Fall back to a manual `impl` only when the conversion needs

129− custom logic, such as validation or normalization. `derive_more` is

130− already a workspace dependency.

131−7. **String-literal unions become `enum`s.** If upstream uses a string

132− literal type or a union of string literals (for example,

133− `'auto' | 'always' | 'never'`), model it as a Rust `enum`, not a

134− newtype wrapper. The set of valid values is closed, so encode that.

135−8. **Template literal types are branded strings.** If upstream uses a

136− string template literal type (for example,

137− ``` `${string}@${string}` ```), treat it the same as a branded string

138− type. Use a newtype wrapper with the validation discipline from rules

139− 2 through 5 above.

140−

141−## Follow the project guides

142−

143−1. Follow the contributing guide in [`CONTRIBUTING.md`](./CONTRIBUTING.md), and **ALWAYS** double-check before committing. It covers commit message format, writing style, setup, and the automated checks to run before committing.

144−2. Follow the code style guide in [`CODE_STYLE_GUIDE.md`](./CODE_STYLE_GUIDE.md), and **ALWAYS** double-check before committing. It covers code-level conventions not enforced by tooling: imports, modules, naming, ownership and borrowing, parameter type selection, trait bounds, pattern matching, `pipe-trait`, error handling, test layout, logging during tests, and cloning of `Arc` and `Rc`.

145−

146−## Repo layout (inside `pnpm/`)

147−

148−- `crates/` — library and binary crates that make up pacquet.

149− - `cli`, `package-manager`, `package-manifest`, `lockfile`, `store-dir`,

150− `tarball`, `registry`, `network`, `npmrc`, `fs`, `executor`,

151− `diagnostics`, `testing-utils`.

152−- `tasks/` — developer tooling: `integrated-benchmark`, `micro-benchmark`,

153− `registry-mock`.

154−- `CONTRIBUTING.md` — commit-message format, writing style, setup, and the

155− automated checks to run before submitting. Read it before submitting code.

156−- `CODE_STYLE_GUIDE.md` — manual code-style conventions beyond what `cargo

157− fmt`, `taplo`, and clippy enforce: imports, modules, naming, ownership

158− and borrowing, trait bounds, pattern matching, `pipe-trait`, error

159− handling, test layout, and `Arc`/`Rc` cloning. Read it before submitting

160− code.

161−

162−The Rust workspace (`Cargo.toml`, `Cargo.lock`, `rust-toolchain.toml`,

163−`justfile`, `.cargo/`, `.taplo.toml`, etc.) lives at the **repo root**, not

164−inside `pnpm/`. Run `cargo` and `just` from the repo root.

165−

166−## Commands

167−

168−Prefer `just` recipes when one fits; drop down to `cargo` / `taplo` / etc.

169−directly when you need flags the recipe doesn't expose (e.g. filtering tests

170−by crate or name — see below).

171−

172−- `just ready` — run the same checks CI runs (typos, fmt, check, test, lint).

173− Run this before declaring a task complete.

174−- `just test` — `cargo nextest run`.

175−- `just lint` — `cargo clippy --locked --workspace --all-targets -- --deny warnings`.

176−- `just check` — `cargo check --locked --workspace --all-targets`.

177−- `just fmt` — `cargo fmt` + `taplo format`.

178−- `just cli -- <args>` — run the pacquet binary.

179−- `just registry-mock <args>` — manage the mock registry used by tests.

180−- `just integrated-benchmark <args>` — compare revisions or compare against

181− pnpm itself (see `CONTRIBUTING.md`).

182−

183−Warnings are errors (`--deny warnings` in lint). Do not silence them with

184−`#[allow(...)]` unless there is a specific, justified reason.

185−

186−## Tests

187−

188−- Tests live alongside the code they exercise (standard Cargo layout) plus

189− integration tests under each crate's `tests/`. Shared pacquet fixtures live

190− under `crates/testing-utils/src/fixtures/`; registry package fixtures live

191− under `../pnpr/.fixtures/packages/`.

192−- Snapshot tests use `insta`. When an intentional change alters a snapshot,

193− review the diff carefully, then accept with `cargo insta review`. Never

194− accept snapshot changes blindly.

195−- Tests that need the mocked registry start `pnpr` through

196− `pacquet-testing-utils`; `cargo test` / `cargo nextest run` should not

197− require a separate `just registry-mock launch` step.

198−- When a behavior change spans both stacks, keep their tests in sync — give

199− pacquet a Rust test for the same scenario the TypeScript stack covers (and

200− vice versa) whenever it translates. Matching test coverage is the easiest

201− way to prove behavioral parity.

202−- The active test-porting plan lives in

203− [`plans/TEST_PORTING.md`](./plans/TEST_PORTING.md). It enumerates the

204− upstream TypeScript tests scheduled to be ported (with file paths and line

205− numbers) and the conventions expected of the ports — `known_failures`

206− modules, `pacquet_testing_utils::allow_known_failure!` at the

207− not-yet-implemented boundary, and the practice of temporarily breaking the

208− subject under test to verify the ported test actually catches the

209− regression. Consult it before adding ported tests, and update its

210− checkboxes as items land.

211−- When temporarily breaking an implementation (to prove a test catches the

212− regression, or for any other experiment), revert with `git restore <file>`,

213− never by moving a saved backup copy into place. Cargo's freshness check is

214− mtime-based, and an mtime-preserving restore leaves the binary compiled

215− from the broken source looking fresh — later test runs then fail in

216− impossible-looking, "flaky" ways with nothing pointing at the stale

217− artifact. Details in the "Test the tests" section of

218− [`plans/TEST_PORTING.md`](./plans/TEST_PORTING.md). If test outcomes ever

219− flip with no code change, `touch` the implementation file and rerun before

220− debugging anything else.

221−

222−### No "tolerant" tests for missing tools

223−

224−Tests must not be tolerant of a missing build / runtime environment by

225−silently `return`-ing early when a tool isn't found. Patterns like:

226−

227−```rust

228−fn skip_if_no_git() -> bool {

229− if std::process::Command::new("git").arg("--version").output().is_err() {

230− eprintln!("skipping: `git` not on PATH");

231− return true;

232− }

233− false

234−}

235−

236−#[test]

237−fn my_test() {

238− if skip_if_no_git() {

239− return;

240− }

241− // ...

242−}

36+```text

37+pnpr/

38+ AGENTS.md

39+ crates/

40+ pnpr/ -> package "pnpr"

41+ Cargo.toml

42+ README.md

43+ src/

44+ lib.rs -> library API

45+ main.rs -> binary entry point (ships the `pnpr` binary)

46+ # future sibling crates land here, see "New registry-only crates" below

24347 ```

24448

245−are forbidden. If the test needs a tool, just call into it and let the

246−existing `.unwrap()` / `.expect(...)` panic when the tool is absent — a

247−failing test in an under-provisioned environment is the correct signal.

248−Tolerance defeats the purpose of testing: if the environment really

249−doesn't have the required tools, that's the *environment's* fault and it

250−needs to be fixed.

49+The Rust workspace itself, `rust-toolchain.toml`, `justfile`, and

50+`Cargo.lock` live at the **repo root** — run `cargo` and `just` from there.

51+`pnpr/crates/*` is wired into the root workspace `members`.

25152

252−This applies in particular to `git`, `node`, and `npm` — git is ubiquitous

253−on developer machines, and Node.js is a documented prerequisite for

254−building pnpm. There is no realistic environment in which pacquet's tests

255−should run *and* these tools should be absent.

53+## Code reuse

25654

257−The only marginally acceptable exception is platform-locked tools — APIs

258−or binaries that exist on one OS but not another. Even then, prefer

259−`#[cfg_attr(target_os = "windows", ignore = "...")]` (or the matching

260−`#[cfg(unix)]` gate already used in this crate for `/bin/sh` shims) over a

261−runtime probe-and-skip helper. The gate is visible to `cargo test` and

262−shows up in the test report; a silent `return` does not.

55+**Prefer existing `pacquet-*` crates over writing new code.** Before

56+implementing anything non-trivial, check whether `pacquet-*` already

57+solves it. Candidates worth checking first: `pacquet-tarball`,

58+`pacquet-crypto-hash`, `pacquet-crypto-shasums-file`,

59+`pacquet-package-manifest`, `pacquet-network`, `pacquet-registry`,

60+`pacquet-fs`, `pacquet-diagnostics`. Add a `pacquet-*` crate the same

61+way pacquet crates do: declare it in the root `[workspace.dependencies]`

62+(already done for the pacquet crates) and use `{ workspace = true }`

63+in this crate's `Cargo.toml`.

26364

264−### Running tests narrowly

65+If a piece of code currently inside `pnpm/` turns out to be genuinely

66+shared between the two stacks and the `pacquet-` prefix becomes

67+misleading, propose renaming/relocating it in a dedicated PR — not as a

68+drive-by during feature work.

26569

266−Running the full suite is slow. While iterating, target what you're working

267−on:

70+### New registry-only crates

26871

269−```sh

270−# One crate

271−cargo nextest run -p pacquet-lockfile

72+When the registry needs its own crate (logic that isn't shared with the

73+pnpm port and doesn't fit in `pnpm/`), put it under

74+`pnpr/crates/<short-name>/` and name the package

75+`pnpr-<short-name>` in its `Cargo.toml`. The

76+`pnpr/crates/*` glob in the root workspace `members` picks it up

77+automatically; just add the new crate to `[workspace.dependencies]` at

78+the root with the `pnpr-` prefix so other crates can use

79+`{ workspace = true }`.

27280

273−# One test by name substring

274−cargo nextest run -p pacquet-lockfile <name_substring>

81+Use the `pnpr-` prefix exclusively for registry-only crates.

82+Don't reach for `pacquet-` to name something new on the registry side.

27583

276−# One integration test file

277−cargo nextest run -p pacquet-lockfile --test <file_stem>

278−```

84+## Dependencies

27985

280−Run `just ready` (full suite) before handing the PR off.

86+Same rule as pacquet: a dependency that is already declared in

87+`[workspace.dependencies]` may be used by any crate that needs it.

88+Adding a new third-party crate to the workspace requires an explicit

89+human request (see [`../pnpm/AGENTS.md`](../pnpm/AGENTS.md#things-not-to-do)).

28190

282−## Style

91+## Style, tests, commits

28392

284−`CODE_STYLE_GUIDE.md` is the source of truth. Highlights:

93+Follow the pacquet code-style guide

94+([`../pnpm/CODE_STYLE_GUIDE.md`](../pnpm/CODE_STYLE_GUIDE.md)) and the

95+pacquet contributing guide ([`../pnpm/CONTRIBUTING.md`](../pnpm/CONTRIBUTING.md))

96+for Rust-level conventions — imports, naming, ownership, error handling,

97+test layout. They are written for pacquet but apply to any Rust code in

98+this workspace.

28599

286−- Choose owned vs. borrowed parameters to minimize copies; widen to the most

287− encompassing type (`&Path` over `&PathBuf`, `&str` over `&String`) when it

288− doesn't force extra copies.

289−- Prefer `Arc::clone(&x)` / `Rc::clone(&x)` over `x.clone()` for reference-

290− counted types, so the cost is visible at the call site.

291−- Follow the test-logging guidance in the style guide — log before non-

292− `assert_eq!` assertions, `dbg!` complex structures, skip logging for simple

293− scalar `assert_eq!`.

294−- Follow [Rust API Guidelines](https://rust-lang.github.io/api-guidelines/naming.html)

295− for naming.

296−- **No star imports inside module bodies.** Write `use super::{Foo, bar}`

297− instead of `use super::*;`, and the same for any other glob whose

298− target is a module you control. Two forms stay allowed: external-crate

299− preludes such as `use rayon::prelude::*;` and root-of-module

300− re-exports such as `pub use submodule::*;` in a `lib.rs`. See the

301− "No star imports" section in `CODE_STYLE_GUIDE.md`.

302−

303100 ### Comments

304101

305−Same baseline as [`../AGENTS.md`](../AGENTS.md#comments): write code that explains itself; comments are for the non-obvious *why*, not a translation of the *what*.

102+Follow the repo-wide comment baseline in [`../AGENTS.md`](../AGENTS.md#comments) and the Rust-specific additions in [`../pnpm/AGENTS.md`](../pnpm/AGENTS.md#comments).

306103

307−Rust-specific additions:

104+Commit messages use Conventional Commits with `pnpr` as the scope

105+(`feat(pnpr): ...`, `fix(pnpr): ...`).

308106

309−- **Doc comments (`///`, `//!`) are rustdoc-visible API documentation.** Use them for item contracts. Put implementation-only rationale in regular `//` comments.

310−- **Tests are documentation. Do not duplicate them in prose.** If a behavioral scenario, edge case, failure mode, or worked example is already captured by a test (its name, its setup, its assertions), do not also narrate it in the doc comment on the implementation. The doc comment should state the contract once; the test demonstrates the behavior. The same applies in reverse: a test's own doc comment should not re-explain what the asserts already say, only the *why* if it is not obvious.

311−- **`// SAFETY:`, `// TODO:`, and similar prefixes are the exception.** They signal hidden invariants or known follow-ups that a reader cannot recover from the code alone.

107+Run the same checks pacquet does before declaring work done:

312108

313−Prefer renaming, restructuring, or extracting a helper over leaving a comment. Reach for prose only when the right names and types genuinely cannot carry the information.

314−

315−### Preserve existing method chains

316−

317−When editing existing code, do not break a method chain (including `pipe-trait`

318−`.pipe(...)` chains) into intermediate `let` bindings unless you can justify

319−the rewrite. Valid justifications include a chain that fails to compile after

320−your edit, a borrow checker rejection, a meaningful performance win from

321−splitting it up, or any other concrete reason the chain cannot stay as it is.

322−Refactoring for style alone is not a justification when the task is something

323−else. Keep the surrounding code shape intact and confine your edits to what

324−the task asks for.

325−

326−When the change you need can fit inside the existing chain, keep it there.

327−For example, swapping a `PathBuf::from` allocation for a `Path::new` borrow:

328−

329−```diff

330− output

331− .stdout

332− .pipe(String::from_utf8)

333− .expect("convert stdout to UTF-8")

334− .trim_end()

335−- .pipe(PathBuf::from)

336−+ .pipe(Path::new)

337− .parent()

338− .expect("parent of root manifest")

339− .to_path_buf()

109+```sh

110+just check # cargo check --locked --workspace --all-targets

111+just test # cargo nextest run

112+just lint # cargo clippy --workspace --all-targets -- --deny warnings

113+just fmt # cargo fmt + taplo format

340114 ```

341−

342−Do not flatten the chain just because you happen to be editing nearby:

343−

344−```diff

345−-output

346−- .stdout

347−- .pipe(String::from_utf8)

348−- .expect("convert stdout to UTF-8")

349−- .trim_end()

350−- .pipe(PathBuf::from)

351−- .parent()

352−- .expect("parent of root manifest")

353−- .to_path_buf()

354−+let stdout = String::from_utf8(output.stdout).expect("convert stdout to UTF-8");

355−+Path::new(stdout.trim_end()).parent().expect("parent of root manifest").to_path_buf()

356−```

357−

358−If you do need to break a chain, state the justification in your reply, the

359−commit message, or the PR description so a reviewer can confirm the rewrite

360−was warranted. If the rewrite is purely stylistic, raise it with the user as

361−its own change rather than including it in an unrelated edit.

362−

363−## Code reuse (pacquet specifics)

364−

365−The general "search before you write / extract shared code / prefer mature

366−crates / keep deps at the right level" rules from

367−[`../AGENTS.md`](../AGENTS.md#code-reuse-and-avoiding-duplication) apply.

368−Pacquet-specific notes:

369−

370−- Shared helpers tend to live in `crates/fs`, `crates/testing-utils`, and

371− `crates/diagnostics` — check there first.

372−- Check whether the workspace already depends on something suitable (see

373− `[workspace.dependencies]` in the root `Cargo.toml`) before adding a new

374− dependency.

375−- **Keep dependencies at the right level.** Add a new dependency to the

376− specific crate that needs it, not to the workspace root or to a shared

377− crate unless multiple crates actually depend on it.

378−

379−## Errors and diagnostics

380−

381−User-facing errors go through `miette` via the `pacquet-diagnostics` crate.

382−Match pnpm's error codes and messages where pnpm defines them — error codes

383−are part of the public contract, not implementation detail. See

384−<https://pnpm.io/errors> for the canonical list.

385−

386−## Commit and PR hygiene

387−

388−- Keep commits focused. A bug fix commit should not also refactor or

389− reformat unrelated code.

390−- When a change has a counterpart in the TypeScript pnpm CLI, land both

391− together; if they must be split, cross-reference the matching PR so a

392− reviewer can confirm the two stacks stay in sync.

393−- Run `just ready` before pushing.

394−- The repo-wide husky `pre-push` hook runs `pnpm/scripts/pre-push-rust.sh`,

395− which checks `rustfmt`, `taplo`, `cargo clippy` (with `--all-targets -D

396− warnings`), `cargo doc` (with `RUSTDOCFLAGS=-D warnings`), and `cargo

397− dylint`. Make sure your environment

398− can run cargo (the hook needs it) before pushing; `cargo-dylint` is

399− detected at runtime and skipped with a warning if not installed.

400−

401−### Commit messages

402−

403−Conventional Commits applies (see

404−[`../AGENTS.md`](../AGENTS.md#commit-messages) for the full type list). Use

405−a scope that names the crate or area being touched, matching the existing

406−history (`git log --oneline` for examples). Pacquet adds one type beyond the

407−standard list:

408−

409−- `bench`: benchmark-only changes.

410−

411−Examples (from this repo's history):

412−

413−```

414−fix(network): set explicit timeouts on default reqwest client

415−feat(lockfile): support npm-alias dependencies in snapshots

416−perf(store-dir): share one read-only StoreIndex across cache lookups

417−```

418−

419−## Things not to do

420−

421−- Do not add a feature, flag, or behavior to one stack without making the

422− same change to the other. The two move together.

423−- Do not change lockfile format, store layout, `.npmrc` semantics, or CLI

424− surface in only one stack — those are the shared contract and must change

425− in both at once.

426−- A dependency that is already declared in `[workspace.dependencies]` in the

427− root `Cargo.toml` may be added to any crate that needs it.

428−- Do not add a dependency that is not already declared in the workspace

429− without an explicit human request. If there is a clear benefit and

430− justification for pulling in a new third-party crate, ask the human to

431− approve it and to add it to `[workspace.dependencies]` rather than adding

432− it yourself. Consult `deny.toml` when evaluating candidates.

433−- Do not introduce `unsafe` without a clear justification and review.

434−- Do not disable lints, tests, or CI checks to make a PR green.

435115