responsive.mobile text overflow

responsive.mobile-text-overflow

Rule ID: responsive.mobile-text-overflow Severity: WARN Category: responsive Target Standards: W3C CSS Text Module Level 3 (Wrapping and Breaking Text), WCAG 2.2 SC 1.4.10 (Reflow - Level AA)

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1. Overview & Core Invariant

Warns when whitespace-nowrap text or code blocks lack truncation, word breaking, or horizontal scroll wrappers

Core Invariant:

"Containers declaring 'whitespace-nowrap' must provide overflow mitigation ('truncate', 'overflow-hidden', 'overflow-x-auto'), and inline '' blocks must provide word breaking ('break-all', 'break-words') or horizontal scroll ancestors."

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2. Technical Grounding & Engine Realities

Dynamic strings such as URLs, authentication tokens, UUIDs, IBANs, and email addresses contain no whitespace. When 'whitespace-nowrap' is declared on narrow smartphone screens (360px) without truncation or scroll containment, the text forces the container beyond the viewport.

Similarly, inline code elements ('') default to unbreaking monospace text. Without 'break-all' or a scrollable parent, long code snippets tear mobile page layouts.

Using 'truncate', 'break-words', or enclosing code inside a scrollable wrapper maintains layout boundaries and satisfies WCAG Reflow requirements.

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3. Vulnerability & Risk Taxonomy

Risk Vector	Severity	Impact
Mobile Layout Breakage via Long Unbroken Strings	MEDIUM	Unbroken URLs or tokens force text containers to stretch horizontally outside the 360px mobile viewport.
Loss of WCAG 2.2 Reflow Compliance	LOW	Users must scroll both horizontally and vertically to read content at 400% zoom or compact viewports.

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4. Non-Compliant Code Patterns (Bad Examples)

TSX (whitespace-nowrap text container without truncation or scroll containment):

<div className="whitespace-nowrap text-sm text-foreground">
  <span>Token Transaksi: {transactionHash}</span>
</div>

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5. Compliant Implementation Patterns (Good Examples)

TSX (Protected text container with truncate):

<div className="whitespace-nowrap truncate text-sm text-foreground">
  <span>Token Transaksi: {transactionHash}</span>
</div>

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

This rule evaluates source code through the standard AST inspection pipeline:

flowchart TD
    Node["AST Node (Astro / TSX element)"] --> Inspect["1. Inspect Element & Attributes"]
    Inspect --> Invariant{"2. Evaluate Rule Invariant"}
    Invariant -- "Compliant" --> Safe["Pass"]
    Invariant -- "Non-Compliant" --> IgnoreCheck{"3. Check charites:ignore directive"}
    IgnoreCheck -- "Ignored" --> Safe
    IgnoreCheck -- "Not Ignored" --> Diag["4. Emit Diagnostic: responsive.mobile-text-overflow"]

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Step-by-Step Evaluation:

1. AST Traversal: Visits normalized ir.Node structures during AST streaming.
2. Invariant Check: Compares node attributes against rule invariants.
3. Directive Suppression Check: Honors inline charites:ignore responsive.mobile-text-overflow directives.
4. Diagnostic Emission: Emits compiler-grade diagnostic on invariant violation.

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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/responsive.mobile-text-overflow/:

flowchart TD
    subgraph GoldenCorpus ["1-SSOT Tri-Corpus Test Matrix for responsive.mobile-text-overflow"]
        subgraph P ["Positive Corpus (tests/correctness/responsive.mobile-text-overflow/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/responsive.mobile-text-overflow/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/responsive.mobile-text-overflow/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 responsive.mobile-text-overflow intentional exception -->

// charites:ignore responsive.mobile-text-overflow intentional exception

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9. Configuration Reference (charites.yaml)

rules:
  responsive.mobile-text-overflow:
    severity: warn # error | warn | info | off