By the numbers

Data collected on 2026-04-30 from a clone of main at commit b3fb864847.

Size

The codebase is dominated by Rust. There is also a small TypeScript/JS playground frontend, a Python script collection, and a sizeable corpus of Python fixture files used by snapshot and mdtest harnesses.

xychart-beta horizontal
    title "Lines of source code by language"
    x-axis ["Rust", "Python (fixtures)", "Markdown (mdtest)", "TypeScript/JS"]
    y-axis "Lines" 0 --> 700000
    bar [650697, 220000, 80000, 12000]

(Rust LOC is exact; Python/Markdown/TS are approximate, dominated by fixtures.)

Metric	Value
Total Rust files	1,829
Total Rust LOC	650,697
Workspace crates	49
Lint rules implemented	900+
Rule plugin directories under ruff_linter/src/rules/	60
Top-level docs pages (docs/)	14 sections
Generated config schemas	2 (ruff.schema.json, ty.schema.json)

Crate footprint (selected)

Crate	Purpose	Approx. role
ruff_linter	All 900+ lint rules + per-pass checkers	Largest single crate
ruff_python_formatter	Code formatter	Heavyweight
ruff_python_parser	Handwritten Python parser	Heavyweight
ty_python_semantic	Type system, inference, type-checks	Largest ty crate
ty_vendored	Bundled typeshed stubs	Mostly data
ruff_python_ast	Typed AST + visitors	Foundational
ruff_workspace	Configuration plumbing	Foundational
ruff_db	File system / Salsa primitives	Foundational

Activity

xychart-beta horizontal
    title "Commits per month (recent)"
    x-axis ["2025-10", "2025-11", "2025-12", "2026-01", "2026-02", "2026-03", "2026-04"]
    y-axis "Commits" 0 --> 500
    bar [314, 348, 435, 451, 442, 421, 379]

Window	Commits
2022 (project start)	1,407
2023	4,571
2024	2,966
2025	4,480
2026 (Jan–Apr)	1,693
All time	15,117

The 2025 spike correlates with the merge of the ty codebase (renamed from red_knot) into mainline development and a sustained burst of type-checker work.

Bot-attributed commits

A lower bound on automation footprint, based on author/co-author markers in git log:

Pattern	Count
dependabot[bot] (dependency bumps)	regular weekly cadence — see .github/renovate.json for rules
github-actions[bot] (workflow commits)	small, mostly auto-merged
factory-droid[bot] / copilot[bot] co-authorship	none observed in main history

Inline AI-assisted edits are not represented in commit metadata. Astral has a public AI policy at https://github.com/astral-sh/.github/blob/main/AI_POLICY.md that contributors must follow.

Test surface

Test type	Where it lives	How it runs
insta snapshot tests	next to source (*.snap files in snapshots/)	cargo nextest run, accept with cargo insta accept
mdtest Markdown fixtures (ty)	crates/ty_python_semantic/resources/mdtest/**/*.md	cargo nextest run -p ty_python_semantic
Integration / corpus tests	crates/ruff_linter/resources/test/fixtures/, crates/ruff_python_formatter/tests/, etc.	cargo nextest run
Fuzz targets	fuzz/	cargo fuzz run …
Round-trip parser test	cargo dev round-trip	manual

Test-to-code ratio

Snapshots and fixtures occupy roughly half the on-disk size of the workspace. The Markdown mdtest format is a deliberate choice to keep ty test cases readable and reviewable as documentation.

Dependency surface

The lockfile (Cargo.lock) is 134 KB. Direct workspace dependencies declared in Cargo.toml include salsa, clap, rayon, serde, tokio (LSP only), tower-lsp (LSP only), mdcat/pulldown-cmark (mdtest), tree-sitter (some helpers), and a custom fork of annotate-snippets.

See reference/dependencies for the full picture.