---
phase: 01-scaffold
plan: "01"
subsystem: infra
tags: [rust, duckdb, cdylib, cargo, clippy, rustfmt, cargo-deny, cargo-husky, just]

# Dependency graph
requires: []
provides:
  - Buildable Rust cdylib extension scaffold (cargo build produces libsemantic_views.dylib)
  - Extension entry point via duckdb_entrypoint_c_api macro (duckdb crate re-export)
  - Workspace clippy pedantic lints configured in Cargo.toml
  - Pre-commit hooks via cargo-husky (fmt + clippy on every commit)
  - Developer task runner (Justfile) with setup, build, test, lint, fmt, coverage, clean
  - deny.toml with permissive license allowlist for DuckDB transitive deps
  - CHANGELOG.md in Keep a Changelog format
affects:
  - 01-02 (CI workflows build on this Cargo.toml and src/lib.rs structure)
  - 01-03 (load smoke test requires the cdylib artifact produced here)
  - all future phases (workspace lints and entry point pattern are foundational)

# Tech tracking
tech-stack:
  added:
    - duckdb = "=1.4.4" with loadable-extension feature
    - libduckdb-sys = "=1.4.4"
    - cargo-husky = "1" (dev-dependency, user-hooks feature)
    - just (task runner)
    - cargo-deny (license/advisory gating)
    - cargo-llvm-cov (coverage, installed via just setup)
    - cargo-nextest (test runner, installed via just setup)
  patterns:
    - cdylib crate type for DuckDB-loadable extension binary
    - duckdb_entrypoint_c_api macro from duckdb crate (not separate duckdb_loadable_macros crate in Cargo.toml)
    - workspace.lints.clippy with priority = -1 for correct override precedence
    - unsafe entry point function with full Safety doc section

key-files:
  created:
    - Cargo.toml
    - Cargo.lock
    - src/lib.rs
    - .cargo-husky/hooks/pre-commit
    - rustfmt.toml
    - deny.toml
    - Justfile
    - CHANGELOG.md
  modified: []

key-decisions:
  - "duckdb_entrypoint_c_api is re-exported from the duckdb crate (not a separate duckdb_loadable_macros dep in Cargo.toml) — verified from template source"
  - "workspace.lints.clippy pedantic requires priority = -1 to allow individual lint overrides to take precedence (lint_groups_priority clippy lint enforces this)"
  - "Use _con (ignored) instead of let _ = con to satisfy needless_pass_by_value; Phase 2+ will use the connection"
  - "duckdb version pinned with = prefix (exact version) to match template convention"

patterns-established:
  - "Pattern: workspace lints use { level = 'deny', priority = -1 } for group-level denies to allow per-lint overrides"
  - "Pattern: unsafe extension entry point always includes Safety doc section for missing_safety_doc compliance"
  - "Pattern: cargo-husky user-hooks installed via just setup running cargo test"

requirements-completed: [INFRA-01, STYLE-01, STYLE-02]

# Metrics
duration: 4min
completed: 2026-02-24
---

# Phase 1 Plan 01: Scaffold Summary

**Rust cdylib extension scaffold with duckdb_entrypoint_c_api entry point, workspace pedantic clippy lints, cargo-husky pre-commit hooks, Justfile task runner, and cargo-deny license config**

## Performance

- **Duration:** 4 min
- **Started:** 2026-02-24T00:02:45Z
- **Completed:** 2026-02-24T00:07:17Z
- **Tasks:** 2
- **Files modified:** 8 created

## Accomplishments

- Extension builds as a cdylib (`cargo build` exits 0, produces `target/debug/libsemantic_views.dylib`)
- `cargo fmt --check` exits 0 and `cargo clippy -- -D warnings` exits 0 — zero violations
- Pre-commit hooks via cargo-husky installed on `cargo test`, enforcing fmt + clippy before every commit

## Task Commits

Each task was committed atomically:

1. **Task 1: Initialize Rust extension scaffold** - `93bdc9d` (feat)
2. **Task 2: Configure code quality tools** - `251b6af` (feat)

**Plan metadata:** (docs commit — see below)

## Files Created/Modified

- `Cargo.toml` — cdylib crate type, duckdb =1.4.4, workspace clippy pedantic lints at priority -1, cargo-husky dev dep
- `Cargo.lock` — committed (binary crate convention)
- `src/lib.rs` — extension entry point using `duckdb::duckdb_entrypoint_c_api` macro with Safety doc section
- `.cargo-husky/hooks/pre-commit` — executable hook running `cargo fmt --check` and `cargo clippy -- -D warnings`
- `rustfmt.toml` — `edition = "2021"`, `max_width = 100`
- `deny.toml` — license allowlist covering MIT, Apache-2.0, BSD, ISC, Unicode, OpenSSL, Zlib
- `Justfile` — setup, build, build-release, test, test-rust, lint, fmt, coverage, clean recipes
- `CHANGELOG.md` — Keep a Changelog format with [Unreleased] section

## Decisions Made

- `duckdb_entrypoint_c_api` is re-exported from the `duckdb` crate — no separate `duckdb_loadable_macros` crate needed in Cargo.toml (confirmed from template source; the crate compiles as `duckdb-loadable-macros v0.1.14` transitively but is accessed via `duckdb::duckdb_entrypoint_c_api`)
- Workspace clippy pedantic uses `{ level = "deny", priority = -1 }` syntax — required so individual lint `= "allow"` overrides take precedence over the group
- duckdb version pinned with `=` prefix to match template convention for exact-version binding

## Deviations from Plan

### Auto-fixed Issues

**1. [Rule 1 - Bug] Fixed lint_groups_priority clippy error in Cargo.toml**
- **Found during:** Task 2 (running `cargo clippy -- -D warnings`)
- **Issue:** `pedantic = "deny"` has same priority as individual overrides; clippy lint `lint_groups_priority` flags this as an error — the group would silently win over per-lint allows
- **Fix:** Changed to `pedantic = { level = "deny", priority = -1 }` so individual lint overrides take precedence
- **Files modified:** `Cargo.toml`
- **Verification:** `cargo clippy -- -D warnings` exits 0
- **Committed in:** `251b6af` (Task 2 commit)

**2. [Rule 1 - Bug] Fixed doc_markdown clippy error in src/lib.rs**
- **Found during:** Task 2 (running `cargo clippy -- -D warnings`)
- **Issue:** "DuckDB" in doc comment not wrapped in backticks — flagged by `clippy::doc_markdown` (implied by pedantic)
- **Fix:** Changed `DuckDB` to `` `DuckDB` `` in doc comment
- **Files modified:** `src/lib.rs`
- **Verification:** `cargo clippy -- -D warnings` exits 0
- **Committed in:** `251b6af` (Task 2 commit)

**3. [Rule 2 - Missing Critical] Added Safety doc section to unsafe entry point**
- **Found during:** Task 2 (running `cargo clippy -- -D warnings`)
- **Issue:** Unsafe function missing `# Safety` documentation section — `clippy::missing_safety_doc` flagged
- **Fix:** Added full Safety doc section explaining the FFI boundary contract
- **Files modified:** `src/lib.rs`
- **Verification:** `cargo clippy -- -D warnings` exits 0
- **Committed in:** `251b6af` (Task 2 commit)

**4. [Rule 1 - Bug] Fixed needless_pass_by_value for Connection parameter**
- **Found during:** Task 2 (running `cargo clippy -- -D warnings`)
- **Issue:** `con: Connection` passed by value but not consumed — `clippy::needless_pass_by_value` flagged
- **Fix:** Renamed to `_con: Connection` (prefix underscore suppresses unused variable warning while keeping the parameter name meaningful)
- **Files modified:** `src/lib.rs`
- **Verification:** `cargo clippy -- -D warnings` exits 0
- **Committed in:** `251b6af` (Task 2 commit)

---

**Total deviations:** 4 auto-fixed (3 Rule 1 bugs, 1 Rule 2 missing critical)
**Impact on plan:** All fixes were necessary for `cargo clippy -- -D warnings` to exit 0. No scope creep. The plan's `done` criteria required zero clippy violations.

## Issues Encountered

None beyond the auto-fixed clippy violations documented above.

## User Setup Required

None — no external service configuration required.

## Next Phase Readiness

- Rust scaffold complete. Plan 02 (CI workflows) can be executed — it builds `.github/workflows/` on top of this Cargo.toml structure.
- Plan 03 (load smoke test) can proceed after Plan 02 CI is in place.
- Phase 2+ (Storage/DDL) will register functions via the `_con: Connection` parameter in `extension_entrypoint`.

## Self-Check: PASSED

- FOUND: Cargo.toml
- FOUND: Cargo.lock
- FOUND: src/lib.rs
- FOUND: .cargo-husky/hooks/pre-commit
- FOUND: rustfmt.toml
- FOUND: deny.toml
- FOUND: Justfile
- FOUND: CHANGELOG.md
- FOUND: .planning/phases/01-scaffold/01-01-SUMMARY.md
- FOUND: commit 93bdc9d (feat: initialize Rust extension scaffold)
- FOUND: commit 251b6af (feat: add code quality tools and fix clippy pedantic violations)

---
*Phase: 01-scaffold*
*Completed: 2026-02-24*
