ux.unbounded async flag

ux.unbounded-async-flag

Rule ID: ux.unbounded-async-flag Severity: ERROR Category: ux Target Standards: Mental Model Continuity & Deadlock Prevention, Nielsen Heuristic #1: Visibility of System Status, ISO 9241-110 Ergonomics of Human-System Interaction (Error Tolerance)

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1. Overview & Core Invariant

Detects async handlers setting loading flags without guaranteed reset in finally/catch exit paths

Core Invariant:

"Async operations setting loading state before 'await' must guarantee state reset in all exit paths or a 'finally' block."

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2. Technical Grounding & Engine Realities

When asynchronous functions activate loading state (e.g. 'setLoading(true)') before awaiting a network operation and fail to ensure that the flag is reset in a 'finally' block or error handler, any unexpected rejection (500 internal server error, timeout, network dropout) leaves the UI permanently frozen in a loading spinner.

Users can neither re-try the action nor interact with adjacent controls, creating an unrecoverable dead end.

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3. Vulnerability & Risk Taxonomy

Risk Vector	Severity	Impact
Permanent UI Lockup & Infinite Spinner Deadlock	HIGH	Failed API requests leave spinners active indefinitely, blocking subsequent interactions and forcing users to hard-refresh.
Silent Failure Masking	HIGH	Users believe an operation is still in flight even after the underlying request failed and aborted.

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4. Non-Compliant Code Patterns (Bad Examples)

TSX (Loading state activated before await without reset in catch/finally block):

<button
  onClick={async () => {
    setLoading(true);
    try {
      await api.fetchUsers();
    } catch (err) {
      console.error(err);
      // setLoading(false) terlupakan! Spinner berputar selamanya saat API gagal.
    }
  }}
>
  Muat Data
</button>

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5. Compliant Implementation Patterns (Good Examples)

TSX (Guaranteed loading reset in finally block ensuring UI unlock under all outcomes):

<button
  onClick={async () => {
    setLoading(true);
    try {
      await api.fetchUsers();
    } finally {
      setLoading(false);
    }
  }}
>
  Muat Data
</button>

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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: ux.unbounded-async-flag"]

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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 ux.unbounded-async-flag 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/ux.unbounded-async-flag/:

flowchart TD
    subgraph GoldenCorpus ["1-SSOT Tri-Corpus Test Matrix for ux.unbounded-async-flag"]
        subgraph P ["Positive Corpus (tests/correctness/ux.unbounded-async-flag/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/ux.unbounded-async-flag/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/ux.unbounded-async-flag/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 ux.unbounded-async-flag intentional exception -->

// charites:ignore ux.unbounded-async-flag intentional exception

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9. Configuration Reference (charites.yaml)

rules:
  ux.unbounded-async-flag:
    severity: error # error | warn | info | off