refactor+fix: migrate utils, narrow focusability check, normalize aria-hidden (Copilot review)

Author: johanrd

lib/utils/is-native-element.js

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+'use strict';
+
+const htmlTags = require('html-tags');
+const svgTags = require('svg-tags');
+const { mathmlTagNames } = require('mathml-tag-names');
+
+// Authoritative set of native element tag names. Mirrors the approach
+// established by #2689 (template-no-block-params-for-html-elements), which
+// the maintainer requires for component-vs-element discrimination in this
+// plugin. Heuristic approaches (PascalCase detection, etc.) were explicitly
+// rejected there because a lowercase tag CAN be a component in GJS/GTS when
+// the name is bound in scope (e.g. `const div = MyComponent; <div />`).
+const ELEMENT_TAGS = new Set([...htmlTags, ...svgTags, ...mathmlTagNames]);
+
+/**
+ * Returns true if the Glimmer element node is a native HTML / SVG / MathML
+ * element — i.e. the tag name is in the authoritative list AND is not
+ * shadowed by an in-scope binding.
+ *
+ * "Native" here means **spec-registered tag name** (in the HTML, SVG, or
+ * MathML spec registries, reached via the `html-tags` / `svg-tags` /
+ * `mathml-tag-names` packages). It is NOT the same as:
+ *
+ *  - "native accessibility" / "widget-ness" — see `interactive-roles.js`
+ *    (aria-query widget taxonomy; an ARIA-tree-semantics question)
+ *  - "native interactive content" / "focus behavior" — see
+ *    `html-interactive-content.js` (HTML §3.2.5.2.7; an HTML-content-model
+ *    question about which tags can be nested inside what)
+ *  - "natively focusable" / sequential-focus — see HTML §6.6.3
+ *
+ * This util answers only: "is this tag a first-class built-in element of one
+ * of the three markup-language standards, rather than a component invocation
+ * or a shadowed local binding?" Callers compose it with the other utils
+ * above when they need a more specific question (see e.g. `template-no-
+ * noninteractive-tabindex`, which consults both this and
+ * `html-interactive-content`).
+ *
+ * Returns false for:
+ *  - components (PascalCase, dotted, @-prefixed, this.-prefixed, ::-namespaced —
+ *    none of these tag names appear in the HTML/SVG/MathML lists)
+ *  - custom elements (`<my-widget>`) — accepted false negative; the web-
+ *    components namespace is open and can't be enumerated
+ *  - scope-bound identifiers (`<div>` when `div` is a local `let` / `const` /
+ *    import / block-param in the enclosing scope)
+ *
+ * @param {object} node - GlimmerElementNode
+ * @param {object} [sourceCode] - ESLint SourceCode, for scope lookup. When
+ *   omitted, the scope check is skipped (the result is then list-based only —
+ *   suitable for unit tests).
+ */
+function isNativeElement(node, sourceCode) {
+  if (!node || typeof node.tag !== 'string') {
+    return false;
+  }
+  if (!ELEMENT_TAGS.has(node.tag)) {
+    return false;
+  }
+  if (!sourceCode || !node.parent) {
+    return true;
+  }
+  const scope = sourceCode.getScope(node.parent);
+  const firstPart = node.parts && node.parts[0];
+  if (firstPart && scope.references.some((ref) => ref.identifier === firstPart)) {
+    return false;
+  }
+  return true;
+}
+
+/**
+ * Inverse of {@link isNativeElement}. Returns true when the node should NOT
+ * be treated as a native HTML element — either because it's a component
+ * invocation (PascalCase, dotted, @-prefixed, this.-prefixed, custom element)
+ * OR a tag name that's shadowed by a scope binding.
+ */
+function isComponentInvocation(node, sourceCode) {
+  return !isNativeElement(node, sourceCode);
+}
+
+module.exports = { isNativeElement, isComponentInvocation, ELEMENT_TAGS };

tests/lib/utils/is-native-element-test.js

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+'use strict';
+
+const { isNativeElement, ELEMENT_TAGS } = require('../../../lib/utils/is-native-element');
+
+// Tests exercise the list-lookup path only. Scope-based shadowing is covered
+// by the rule-level test suites (see tests/lib/rules/template-no-block-params-
+// for-html-elements.js and siblings) because it requires a real ESLint
+// SourceCode / scope manager that's only built up by the rule tester.
+
+describe('isNativeElement — list-only behavior (no sourceCode)', () => {
+  it('returns true for lowercase HTML tag names', () => {
+    expect(isNativeElement({ tag: 'div' })).toBe(true);
+    expect(isNativeElement({ tag: 'article' })).toBe(true);
+    expect(isNativeElement({ tag: 'h1' })).toBe(true);
+    expect(isNativeElement({ tag: 'button' })).toBe(true);
+    expect(isNativeElement({ tag: 'form' })).toBe(true);
+    expect(isNativeElement({ tag: 'section' })).toBe(true);
+  });
+
+  it('returns true for SVG tag names', () => {
+    expect(isNativeElement({ tag: 'svg' })).toBe(true);
+    expect(isNativeElement({ tag: 'circle' })).toBe(true);
+    expect(isNativeElement({ tag: 'path' })).toBe(true);
+  });
+
+  it('returns true for MathML tag names', () => {
+    expect(isNativeElement({ tag: 'mfrac' })).toBe(true);
+    expect(isNativeElement({ tag: 'math' })).toBe(true);
+  });
+
+  it('returns false for PascalCase component tags', () => {
+    expect(isNativeElement({ tag: 'Button' })).toBe(false);
+    expect(isNativeElement({ tag: 'MyWidget' })).toBe(false);
+    // Native-tag names in PascalCase — the core bug case.
+    expect(isNativeElement({ tag: 'Article' })).toBe(false);
+    expect(isNativeElement({ tag: 'Form' })).toBe(false);
+    expect(isNativeElement({ tag: 'Main' })).toBe(false);
+    expect(isNativeElement({ tag: 'Nav' })).toBe(false);
+    expect(isNativeElement({ tag: 'Section' })).toBe(false);
+    expect(isNativeElement({ tag: 'Table' })).toBe(false);
+  });
+
+  it('returns false for named-arg invocations', () => {
+    expect(isNativeElement({ tag: '@heading' })).toBe(false);
+    expect(isNativeElement({ tag: '@tag.foo' })).toBe(false);
+  });
+
+  it('returns false for this-path invocations', () => {
+    expect(isNativeElement({ tag: 'this.myComponent' })).toBe(false);
+    expect(isNativeElement({ tag: 'this.comp.sub' })).toBe(false);
+  });
+
+  it('returns false for dot-path invocations', () => {
+    expect(isNativeElement({ tag: 'foo.bar' })).toBe(false);
+    expect(isNativeElement({ tag: 'ns.widget' })).toBe(false);
+  });
+
+  it('returns false for named-block / namespaced invocations', () => {
+    expect(isNativeElement({ tag: 'foo::bar' })).toBe(false);
+    expect(isNativeElement({ tag: 'Foo::Bar' })).toBe(false);
+  });
+
+  it('returns false for custom elements (accepted false negative)', () => {
+    // Custom elements aren't in the html-tags/svg-tags/mathml-tag-names
+    // allowlists. They're treated as "not a native element" so downstream
+    // rules skip them — matches the convention established in PR #2689.
+    expect(isNativeElement({ tag: 'my-element' })).toBe(false);
+    expect(isNativeElement({ tag: 'x-foo' })).toBe(false);
+  });
+
+  it('returns false for empty / missing / non-string tag', () => {
+    expect(isNativeElement({ tag: '' })).toBe(false);
+    expect(isNativeElement({ tag: undefined })).toBe(false);
+    expect(isNativeElement({ tag: null })).toBe(false);
+    expect(isNativeElement({ tag: 123 })).toBe(false);
+    expect(isNativeElement({})).toBe(false);
+    expect(isNativeElement()).toBe(false);
+    expect(isNativeElement(null)).toBe(false);
+  });
+});
+
+describe('ELEMENT_TAGS', () => {
+  it('includes all HTML, SVG, and MathML tag names', () => {
+    // Sanity check — if this ever drops below a reasonable size, one of the
+    // underlying packages has changed contract.
+    expect(ELEMENT_TAGS.size).toBeGreaterThan(200);
+    expect(ELEMENT_TAGS.has('div')).toBe(true);
+    expect(ELEMENT_TAGS.has('circle')).toBe(true);
+    expect(ELEMENT_TAGS.has('mfrac')).toBe(true);
+  });
+});