fix(template-require-mandatory-role-attributes): skip abstract roles in fallback walk (Copilot review)

ARIA §5.3 marks certain roles as 'Abstract' — widget, input, command,
section, landmark, etc. — as ontology categories that must not be used
in content. Per §4.1 role-fallback semantics, UAs skip these in the
fallback resolution. Our previous impl treated any roles.get() hit as
recognised, so role='widget button' resolved to 'widget' and bailed
without checking button's required attrs (silent false negative).

Now filter roleDefinition.abstract alongside the existing undefined
check; aligns with sibling rules that already apply this filter.

Author: johanrd

lib/rules/template-require-mandatory-role-attributes.js

@@ -34,11 +34,13 @@ function splitRoleTokens(value) {
 // For an ARIA role-fallback list like "combobox listbox", check required
 // attributes against the FIRST recognised role (the primary) per ARIA 1.2
 // role-fallback semantics — a user agent picks the first role it recognises.
+// Abstract roles (widget, input, command, section, … — ARIA §5.3) are
+// ontology categories, not valid authoring roles, so UAs skip them too.
 // Diverges from jsx-a11y, which validates every recognised token.
 function getMissingRequiredAttributes(roleTokens, foundAriaAttributes) {
   for (const role of roleTokens) {
     const roleDefinition = roles.get(role);
-    if (!roleDefinition) {
+    if (!roleDefinition || roleDefinition.abstract) {
       continue;
     }
     const requiredAttributes = Object.keys(roleDefinition.requiredProps);

tests/lib/rules/template-require-mandatory-role-attributes.js

@@ -30,6 +30,12 @@ ruleTester.run('template-require-mandatory-role-attributes', rule, {
     '<template><div role="COMBOBOX" aria-expanded="false" aria-controls="ctrl" /></template>',
     // Role fallback list — primary role's required attributes are satisfied.
     '<template><div role="combobox listbox" aria-expanded="false" aria-controls="ctrl" /></template>',
+    // Abstract roles (ARIA §5.3) are skipped per §4.1 fallback semantics —
+    // `widget` isn't an authoring role, so the UA walks past it to the next
+    // recognised token. Here `button` has no required attrs → valid.
+    '<template><div role="widget button" /></template>',
+    // Abstract role followed by a concrete role that IS satisfied.
+    '<template><div role="command slider" aria-valuenow="0" /></template>',
   ],
 
   invalid: [
@@ -101,6 +107,18 @@ ruleTester.run('template-require-mandatory-role-attributes', rule, {
         },
       ],
     },
+    // Abstract role (`widget`) followed by a concrete role that's missing
+    // required attrs — UA skips the abstract, lands on `slider`, which
+    // requires aria-valuenow.
+    {
+      code: '<template><div role="widget slider"></div></template>',
+      output: null,
+      errors: [
+        {
+          message: 'The attribute aria-valuenow is required by the role slider',
+        },
+      ],
+    },
   ],
 });