HudLint

Overview

HudLint scans HudsonKit source for raw design values — hardcoded colors, font sizes, padding, frame dimensions, corner radii, opacity literals — and fails the build when it finds them. The token vocabulary (HudPalette, HudSpacing, HudRadius, HudFont, HudTextSize, HudLayout) is the contract; HudLint enforces it.

The motivation is design-system drift: once a Color(red:0.1, green:0.1, blue:0.12) or .padding(13) lands in one file, the next contributor copies it, and a year later the design system is a folder of conventions nobody reads. Compile-time enforcement beats convention. A linter that fails CI is the only thing that holds.

Lives at packages/native/apple/HudsonKit/Tools/HudLint/ — a standalone Swift Package with two products: HudLintCore (library) and hudlint (CLI).

What it catches

Default rules cover five categories:

Rules are stateless regexes evaluated line-by-line — see Sources/HudLintCore/Rules.swift. The set is intentionally narrow; broader analyses are out of scope for V1.

macOS integration — Makefile

The macOS demo wires HudLint into the build chain:

HUDLINT := $(TOOL_DIR)/.build/release/hudlint

$(HUDLINT):
	@cd $(TOOL_DIR) && swift build -c release --product hudlint

lint: $(HUDLINT)
	@$(HUDLINT) \
		--root $(KIT_ROOT)/Sources \
		--root $(KIT_ROOT)/Demo/HudsonKitDemo \
		--format plain

build: lint
	@swift build

make build and make run both depend on lint, so a violation fails the build before swift build runs.

iOS integration — Run Script Build Phase

For the iOS demo, add a Run Script Build Phase ahead of "Compile Sources":

# HudLint — fail the build on design-token drift
HUDLINT="${SRCROOT}/../HudsonKit/Tools/HudLint/.build/release/hudlint"
if [ ! -x "$HUDLINT" ]; then
  (cd "${SRCROOT}/../HudsonKit/Tools/HudLint" && swift build -c release --product hudlint)
fi
"$HUDLINT" --root "${SRCROOT}/Sources" --format xcode

--format xcode emits <file>:<line>:<col>: error: <msg> so violations appear inline in the Xcode issue navigator.

Escape hatch

When you genuinely need a raw value, disable the next line:

// hudlint:disable next-line geometry
.frame(width: 320, height: 44)

// Multiple categories on one line:
// hudlint:disable next-line palette,opacity
Color.black.opacity(0.92)

// Disable everything (rare):
// hudlint:disable next-line
let x = Color(red: 1, green: 0, blue: 0)

Directives consume exactly one line and must sit immediately above the offending code.

Configuration

Path-based ignores live in .hudlintignore next to the lint root. Gitignore-flavored — ** matches any segments, * within a segment, leading / anchors to root. Generated code and vendored deps belong here.

CLI

hudlint --root <dir> [--root <dir> ...] \
        [--config <path>] \
        [--format xcode|plain|json] \
        [--warn] \
        [--quiet]

Exit status: 0 clean, 1 violations in strict mode, 2 usage error.