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github-actions[bot] edited this page Sep 6, 2026 · 2 revisions

pwa.service-worker-missing

Rule ID: pwa.service-worker-missing Severity: WARN Category: pwa Target Standards: W3C Service Workers (Document Integration), W3C Web App Manifest (Installation Requirements), Google Chrome PWA Criteria (Offline Capability)

1. Overview & Core Invariant

Warns when an HTML document head links to a Web App Manifest but lacks a Service Worker registration in the document

Core Invariant:

"When an HTML document head links to a Web App Manifest, the document must register a Service Worker via navigator.serviceWorker.register or an external worker script."

2. Technical Grounding & Engine Realities

A Progressive Web App requires a registered Service Worker to cache shell assets, intercept network requests during outages, and satisfy full mobile installability audits.

Linking a manifest file without registering a Service Worker leaves the application behaving like a conventional static website, incapable of offline execution or background updates.

3. Vulnerability & Risk Taxonomy

Risk Vector Severity Impact
Lack of Offline Capability MEDIUM Users cannot open or use the application when device connectivity is intermittent or offline.
Failed Installability Criteria LOW Modern mobile browsers will not trigger automated installation banners without an active Service Worker.

4. Non-Compliant Code Patterns (Bad Examples)

TSX (Document head links to manifest but no Service Worker is registered):

<head>
  <title>Layanan Desa</title>
  <link rel="manifest" href="/manifest.webmanifest" />
</head>

5. Compliant Implementation Patterns (Good Examples)

TSX (Document head links to manifest and registers a Service Worker):

<head>
  <title>Layanan Desa</title>
  <link rel="manifest" href="/manifest.webmanifest" />
  <script>
    if ('serviceWorker' in navigator) {
      navigator.serviceWorker.register('/sw.js').catch(console.error);
    }
  </script>
</head>

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: pwa.service-worker-missing"]
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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 pwa.service-worker-missing directives.
  4. Diagnostic Emission: Emits compiler-grade diagnostic on invariant violation.

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/pwa.service-worker-missing/:

flowchart TD
    subgraph GoldenCorpus ["1-SSOT Tri-Corpus Test Matrix for pwa.service-worker-missing"]
        subgraph P ["Positive Corpus (tests/correctness/pwa.service-worker-missing/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/pwa.service-worker-missing/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/pwa.service-worker-missing/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.

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 pwa.service-worker-missing intentional exception -->
// charites:ignore pwa.service-worker-missing intentional exception

9. Configuration Reference (charites.yaml)

rules:
  pwa.service-worker-missing:
    severity: warn # error | warn | info | off

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