refactor: extract landmark-roles util (preserving deliberate per-rule region exclusion)

Adds `lib/utils/landmark-roles.js` deriving landmark roles from aria-query
(non-abstract roles with 'landmark' in their superClass chain, filtering
out DPub-ARIA doc-* roles). Exports two sets:

- `ALL_LANDMARK_ROLES` — the 8 WAI-ARIA 1.2 §5.3.4 landmark roles
  (banner, complementary, contentinfo, form, main, navigation, region,
  search).
- `LANDMARK_ROLES` — the 7-role subset excluding `region`, safe for
  static-linting rules that cannot verify accessible names at lint time.

`<section>` only gets the `region` landmark role when it has an
accessible name (aria-label / aria-labelledby / title). Without one,
`<section>` has role `generic` per the WAI-ARIA APG landmark examples:
https://www.w3.org/WAI/ARIA/apg/patterns/landmarks/examples/HTML5.html

A static linter cannot verify that accessible names resolve to non-empty
values at runtime, so rules that enumerate landmarks should use the
7-role subset (`LANDMARK_ROLES`) to avoid false-positive-flagging
unnamed-section nesting/redundancy. Rules that DO verify accessible
names can use `ALL_LANDMARK_ROLES`.

This was the reasoning behind ember-cli#2694 (post-merge-review that dropped
section/region from `template-no-nested-landmark`). An earlier draft of
this PR reversed that fix by treating the exclusion as "drift"; this
revision preserves the exclusion and codifies the reasoning in the
shared util so future rule authors inherit the safe default.

- `template-no-duplicate-landmark-elements` — imports `ALL_LANDMARK_ROLES`
  as `LANDMARK_ROLES`. This rule inspects aria-label / aria-labelledby
  before classifying a node as a landmark (see `getLabel` + dynamic-label
  skip in `GlimmerElementNode`), so it can safely include `region`.
- `template-no-nested-landmark` — imports `LANDMARK_ROLES` (the safe
  subset). Preserves the ember-cli#2694 behavior.
- `template-no-redundant-role` — imports `LANDMARK_ROLES` (the safe
  subset). Also removes the `region: ['section']` entry from
  `ROLE_TO_ELEMENTS` for the same reason — ember-cli#2694's reasoning applies
  here too: `<section role="region">` should not be flagged as redundant
  because we can't verify the section has a name.

- New util tests cover both sets, the DPub exclusion, and non-landmark
  role rejection.
- `template-no-nested-landmark` tests preserve the original valid test
  for nested `role="region"` without accessible names.
- `template-no-redundant-role` tests preserve the original `<div role="region">`
  as valid (div has no implicit role); the previously-regressed test for
  `<section role="region">` flagged-in-landmark-only is no longer present
  because the rule no longer flags that pattern (consistent with ember-cli#2694).

Author: johanrd

lib/rules/template-no-duplicate-landmark-elements.js

@@ -1,3 +1,9 @@
+// This rule inspects aria-label / aria-labelledby before classifying a node
+// as a landmark (see getLabel + the dynamic-label skip in GlimmerElementNode),
+// so it can safely include `region` — it won't flag an unnamed <section> as
+// a landmark duplicate. Use the full spec-listed 8-role set.
+const { ALL_LANDMARK_ROLES: LANDMARK_ROLES } = require('../utils/landmark-roles');
+
 /** @type {import('eslint').Rule.RuleModule} */
 module.exports = {
   meta: {
@@ -33,18 +39,6 @@ module.exports = {
       form: 'form',
     };
 
-    // Landmark ARIA roles
-    const LANDMARK_ROLES = new Set([
-      'banner',
-      'complementary',
-      'contentinfo',
-      'form',
-      'main',
-      'navigation',
-      'region',
-      'search',
-    ]);
-
     // Sectioning elements that strip banner/contentinfo roles from header/footer
     const SECTIONING_ELEMENTS = new Set(['article', 'aside', 'main', 'nav', 'section']);
     const elementStack = [];

lib/rules/template-no-nested-landmark.js

@@ -1,12 +1,4 @@
-const LANDMARK_ROLES = new Set([
-  'banner',
-  'complementary',
-  'contentinfo',
-  'form',
-  'main',
-  'navigation',
-  'search',
-]);
+const { LANDMARK_ROLES } = require('../utils/landmark-roles');
 
 const LANDMARK_ELEMENTS = new Set(['header', 'aside', 'footer', 'form', 'main', 'nav']);
 

lib/rules/template-no-redundant-role.js

@@ -1,4 +1,5 @@
 const { roles } = require('aria-query');
+const { LANDMARK_ROLES } = require('../utils/landmark-roles');
 
 const DEFAULT_CONFIG = {
   checkAllHTMLElements: true,
@@ -19,17 +20,6 @@ function createErrorMessageAnyElement(element, role) {
   return `Use of redundant or invalid role: ${role} on <${element}> detected.`;
 }
 
-// https://www.w3.org/TR/html-aria/#docconformance
-const LANDMARK_ROLES = new Set([
-  'banner',
-  'main',
-  'complementary',
-  'search',
-  'form',
-  'navigation',
-  'contentinfo',
-]);
-
 const ALLOWED_ELEMENT_ROLES = [
   { name: 'nav', role: 'navigation' },
   { name: 'form', role: 'search' },
@@ -114,7 +104,12 @@ const ROLE_TO_ELEMENTS = {
   navigation: ['nav'],
   option: ['option'],
   radio: ['input'],
-  region: ['section'],
+  // `region` is intentionally NOT mapped to `<section>` here. `<section>`
+  // only gets the `region` landmark role when it has an accessible name
+  // (aria-label / aria-labelledby / title); without one it has role
+  // `generic`. A static linter cannot verify accessible-name presence.
+  // Spec: https://www.w3.org/WAI/ARIA/apg/patterns/landmarks/examples/HTML5.html
+  // See #2694 where the same reasoning was applied to template-no-nested-landmark.
   row: ['tr'],
   rowgroup: ['tbody', 'tfoot', 'thead'],
   rowheader: ['th'],

lib/utils/landmark-roles.js

@@ -0,0 +1,47 @@
+'use strict';
+
+const { roles } = require('aria-query');
+
+// The 8 WAI-ARIA 1.2 §5.3.4 Landmark Roles, derived from aria-query:
+// non-abstract roles whose superClass chain includes 'landmark'. DPub-ARIA
+// `doc-*` landmark roles share that superClass but are excluded because this
+// codebase's rules target WAI-ARIA; downstream callers can extend if needed.
+//
+// The 8 roles: banner, complementary, contentinfo, form, main, navigation,
+// region, search.
+const ALL_LANDMARK_ROLES = buildLandmarkRoleSet();
+
+// The subset that's safe for static-linting rules to treat as landmarks
+// without further verification. `region` is EXCLUDED because a static linter
+// cannot determine at lint time whether the element has an accessible name
+// (via aria-label / aria-labelledby / title), which is required for the
+// `region` role to actually apply to a `<section>` per HTML-AAM.
+//
+// See PR #2694 for the full rationale and spec citation
+// (https://www.w3.org/WAI/ARIA/apg/patterns/landmarks/examples/HTML5.html):
+// `<section>` without an accessible name has role `generic`, not `region`.
+//
+// Most a11y rules that enumerate landmarks should use this subset.
+// Rules that DO verify accessible names (e.g. template-no-duplicate-
+// landmark-elements, which inspects aria-label / aria-labelledby before
+// classifying a node as a landmark) should import ALL_LANDMARK_ROLES.
+const LANDMARK_ROLES = new Set([...ALL_LANDMARK_ROLES].filter((role) => role !== 'region'));
+
+function buildLandmarkRoleSet() {
+  const result = new Set();
+  for (const [role, def] of roles) {
+    if (def.abstract) {
+      continue;
+    }
+    if (role.startsWith('doc-')) {
+      continue;
+    }
+    const descendsFromLandmark = (def.superClass || []).some((chain) => chain.includes('landmark'));
+    if (descendsFromLandmark) {
+      result.add(role);
+    }
+  }
+  return result;
+}
+
+module.exports = { LANDMARK_ROLES, ALL_LANDMARK_ROLES };

tests/lib/rules/template-no-nested-landmark.js

@@ -45,7 +45,7 @@ ruleTester.run('template-no-nested-landmark', rule, {
 
     // `<section>` only gets the `region` landmark role when it has an accessible name
     // (aria-label/aria-labelledby/title). Without one it has the generic role — see
-    // https://www.w3.org/TR/html-aam-1.0/#el-section
+    // https://www.w3.org/WAI/ARIA/apg/patterns/landmarks/examples/HTML5.html
     // This rule does not inspect accessible names, so unnamed sections are excluded.
     '<template><section><section>Content</section></section></template>',
     // `role="region"` is the landmark role a named `<section>` gets. Nesting it is

tests/lib/rules/template-no-redundant-role.js

@@ -48,6 +48,7 @@ ruleTester.run('template-no-redundant-role', rule, {
       options: [{ checkAllHTMLElements: false }],
     },
     '<template><input role="combobox"></template>',
+<<<<<<< HEAD
     // <select multiple> has implicit role listbox, so combobox is not redundant.
     '<template><select role="combobox" multiple></select></template>',
     // <select size="5"> (size > 1) has implicit role listbox.
@@ -66,6 +67,13 @@ ruleTester.run('template-no-redundant-role', rule, {
     // <button> resolves to `tab` (non-redundant — button's implicit is
     // `button`, not `tab`). WAI-ARIA §4.1 fallback-list semantics.
     '<template><button role="tab button"></button></template>',
+    // `region` is a landmark role, but <div> has no implicit role — role="region"
+    // on a <div> is not redundant.
+    '<template><div role="region"></div></template>',
+    {
+      code: '<template><div role="region"></div></template>',
+      options: [{ checkAllHTMLElements: false }],
+    },
   ],
   invalid: [
     {

tests/lib/utils/landmark-roles-test.js

@@ -0,0 +1,49 @@
+'use strict';
+
+const { LANDMARK_ROLES, ALL_LANDMARK_ROLES } = require('../../../lib/utils/landmark-roles');
+
+describe('ALL_LANDMARK_ROLES', () => {
+  it('contains exactly the 8 WAI-ARIA 1.2 §5.3.4 landmark roles', () => {
+    expect([...ALL_LANDMARK_ROLES].sort()).toEqual([
+      'banner',
+      'complementary',
+      'contentinfo',
+      'form',
+      'main',
+      'navigation',
+      'region',
+      'search',
+    ]);
+  });
+
+  it('excludes DPub-ARIA doc-* roles', () => {
+    for (const role of ALL_LANDMARK_ROLES) {
+      expect(role.startsWith('doc-')).toBe(false);
+    }
+  });
+});
+
+describe('LANDMARK_ROLES (the statically-verifiable subset)', () => {
+  it('is the 7-role subset of ALL_LANDMARK_ROLES excluding region', () => {
+    expect([...LANDMARK_ROLES].sort()).toEqual([
+      'banner',
+      'complementary',
+      'contentinfo',
+      'form',
+      'main',
+      'navigation',
+      'search',
+    ]);
+  });
+
+  it('excludes region (cannot verify accessible-name presence statically)', () => {
+    expect(LANDMARK_ROLES.has('region')).toBe(false);
+    expect(ALL_LANDMARK_ROLES.has('region')).toBe(true);
+  });
+
+  it('excludes non-landmark roles (button, link, article)', () => {
+    expect(LANDMARK_ROLES.has('button')).toBe(false);
+    expect(LANDMARK_ROLES.has('link')).toBe(false);
+    expect(LANDMARK_ROLES.has('article')).toBe(false);
+  });
+});