theme.hardcode border radius

theme.hardcode-border-radius

Rule ID: theme.hardcode-border-radius Severity: WARN Category: theme Target Standards: W3C DTCG Shape & Radius Tokens, Design System Shape Hierarchy, Nested Curvature Optics Standard

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1. Overview & Core Invariant

Detects hardcoded arbitrary border-radius scalars in Tailwind utility classes

Core Invariant:

"Corner rounding and shape curvature must use standardized shape tokens or CSS variables, never arbitrary raw radius scalars."

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2. Technical Grounding & Engine Realities

Specifying arbitrary border-radius values (e.g. rounded-[7px] or rounded-t-[14px]) harms UI consistency:

1. Geometric Discordance: Components with off-scale radii look disjointed when nested or placed side-by-side.
2. Outer/Inner Radius Mismatch: Nested cards require deliberate radius proportion calculations (R_inner = R_outer - padding) defined by the shape system.
3. Rebranding Vulnerability: Global shape system updates (e.g. switching from square to rounded theme) cannot adapt arbitrary bracket classes.

Charites enforces using standard shape tokens (e.g. rounded-sm, rounded-md, rounded-xl) or token variables (e.g. rounded-[var(--radius)]).

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3. Vulnerability & Risk Taxonomy

Risk Vector	Severity	Impact
Geometric Incoherence	MEDIUM	Arbitrary corner radii make cards, buttons, and inputs clash visually across user interfaces.
Theme Rigidity	HIGH	Hardcoded radius prevents sweeping design system theme modernizations or brand shape adjustments.

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4. Non-Compliant Code Patterns (Bad Examples)

TSX (Arbitrary border radius on button and card):

<button className="rounded-[7px] p-3">Submit</button>

ASTRO (Directional arbitrary radius in Astro component):

<div class="rounded-t-[14px] [border-radius:9px]">Modal Header</div>

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5. Compliant Implementation Patterns (Good Examples)

TSX (Using design system shape tokens):

<button className="rounded-md p-3">Submit</button>

ASTRO (Standard directional rounded tokens):

<div class="rounded-t-xl rounded-b-none">Modal Header</div>

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6. Detection & Verification Pipeline (How The Rule Evaluates Code)

This theme rule evaluates source templates against the project's design token graph:

flowchart TD
    Node["AST Node (Astro / TSX element)"] --> Extract["1. Extract Class Names (e.g. 'hover:bg-primary/10')"]
    Extract --> Strip["2. Strip Variants (hover:, dark:, sm:) -> 'bg-primary/10'"]
    Strip --> Split["3. Split Opacity Modifier -> Utility: 'bg-primary', Opacity: '/10'"]
    Split --> Convention["4. Query TokenConvention (Candidate: '--color-primary-light')"]
    Convention --> GraphQuery{"5. Check Token Graph (Does token exist in active scope?)"}
    GraphQuery -- "No (Banana Test)" --> Safe["Pass (Valid Custom / Untokenized Color)"]
    GraphQuery -- "Yes (Official Token Exists)" --> IgnoreCheck{"6. Check charites:ignore directive"}
    IgnoreCheck -- "Ignored" --> Safe
    IgnoreCheck -- "Not Ignored" --> Diag["7. Emit Diagnostic: theme.hardcode-border-radius with Replacement Suggestion"]

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Step-by-Step Evaluation:

1. AST Node Traversal: internal/analyzer streams JSX/Astro AST elements to the rule's Evaluate visitor.
2. Variant Normalization: Strips responsive (sm:, md:), interaction state (hover:, focus:), and theme (dark:) prefixes to isolate the core utility class.
3. Modifier Extraction: Parses utility segments and extracts slash opacity modifiers.
4. Token Convention Resolution: Consults the TokenConvention adapter to determine the official semantic design token replacement candidate.
5. Token Graph Verification (Banana Test): Queries token.Context to verify that the candidate token is declared in global.css or tokens.json within the element's scope. If not declared, the custom value is permitted without a false-positive diagnostic.
6. Directive Suppression Check: Inspects preceding AST comments for charites:ignore theme.hardcode-border-radius.
7. Diagnostic Emission: Produces a structured diagnostic with line number, column span, and actionable replacement suggestion.

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7. Verification & Test Harness (How The Test Works: 1-SSOT Tri-Corpus)

This rule is rigorously tested and validated across the canonical 1-SSOT Tri-Corpus in tests/correctness/theme.hardcode-border-radius/:

flowchart TD
    subgraph GoldenCorpus ["1-SSOT Tri-Corpus Test Matrix for theme.hardcode-border-radius"]
        subgraph P ["Positive Corpus (tests/correctness/theme.hardcode-border-radius/positive/)"]
            P1["P1: Obvious Direct Violation"]
            P2["P2: Indirect / Variant Concatenation"]
            P3["P3: Helper / clsx / cn Wrapper"]
            P4["P4: Deeply Nested Elements"]
            P5["P5: Aliased Imports / Re-exports"]
        end
        subgraph N ["Negative Corpus (tests/correctness/theme.hardcode-border-radius/negative/)"]
            N1["N1: Valid Design Tokens"]
            N2["N2: Explicit charites:ignore Directive"]
            N3["N3: Third-Party / Vendor Components"]
            N4["N4: Clean Semantic HTML"]
            N5["N5: Untokenized Custom Values (Banana Test)"]
        end
        subgraph A ["Adversarial Corpus (tests/correctness/theme.hardcode-border-radius/adversarial/)"]
            A1["A1: Template Literal Interpolations"]
            A2["A2: Ternary Conditional Expressions"]
            A3["A3: Spread Properties & Dynamic Overrides"]
            A4["A4: Dynamic Object Class Syntax"]
            A5["A5: Shadowed Variable Identifiers"]
            A6["A6: Nested Closures & HOC Wrappers"]
            A7["A7: Obfuscated Classes & Cyclic Tokens"]
        end
    end

    P --> TestRunner["Automated Runner (rule_test.go)"]
    N --> TestRunner
    A --> TestRunner
    TestRunner --> Gates["Quality Gates: Zero Panic, Zero False-Positive, Zero Bypass"]

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• Positive Fixtures (P1-P5): Verified to trigger diagnostics at exact lines and column spans.
• Negative Fixtures (N1-N5): Verified to produce zero diagnostics on valid tokens and legitimate exemptions.
• Adversarial Fixtures (A1-A7): Verified to prevent evasion across dynamic expressions, string interpolations, and cyclic references.

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8. How to Suppress (Ignore Directives)

If this pattern is required for an intentional exception, suppress the diagnostic using the canonical Charites Rule ID:

<!-- charites:ignore theme.hardcode-border-radius intentional exception -->

// charites:ignore theme.hardcode-border-radius intentional exception

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9. Configuration Reference (charites.yaml)

rules:
  theme.hardcode-border-radius:
    severity: warn # error | warn | info | off