fix: narrow input+role exemption to documented pairings

The previous exemption used a cartesian product of
`{checkbox, menuitemcheckbox, menuitemradio, radio, switch}` against
input types `{checkbox, radio}`, which silently accepted undocumented
pairings such as `input[type=checkbox] role=radio` or
`input[type=radio] role=switch`.

Replace that with an explicit whitelist of `{type}:{role}` pairs:

- `input[type=checkbox]` + `role=checkbox` (redundant but valid)
- `input[type=checkbox]` + `role=switch` (WAI-ARIA APG Switch pattern)
- `input[type=checkbox]` + `role=menuitemcheckbox`
- `input[type=radio]` + `role=radio` (redundant but valid)
- `input[type=radio]` + `role=menuitemradio`

The whitelist matches axobject-query's `elementAXObjects` for these
input-role combinations plus the WAI-ARIA APG Switch pattern
(https://www.w3.org/WAI/ARIA/apg/patterns/switch/). Other combinations
remain flagged for missing `aria-checked`.

Also lowercase the `type` attribute value before matching; HTML `type`
keywords are ASCII case-insensitive per the HTML spec, so values like
`Checkbox` must be treated the same as `checkbox`.

Author: johanrd

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

@@ -28,16 +28,18 @@ function getStaticRoleFromMustache(node) {
   return undefined;
 }
 
-// Roles whose required `aria-checked` is supplied natively by <input type="checkbox">
-// or <input type="radio">. Per WAI-ARIA APG, semantic form controls contribute
-// implicit state; e.g. <input type="checkbox" role="switch"> is a documented
-// accessible switch pattern where aria-checked mirrors the native checkedness.
-const ROLES_WITH_IMPLICIT_CHECKED_FROM_INPUT = new Set([
-  'checkbox',
-  'menuitemcheckbox',
-  'menuitemradio',
-  'radio',
-  'switch',
+// `{input type}:{role}` pairings where the required `aria-checked` is supplied
+// natively by the semantic <input>. Pairings match axobject-query's
+// `elementAXObjects` for the input-role combinations and the WAI-ARIA APG
+// Switch pattern (https://www.w3.org/WAI/ARIA/apg/patterns/switch/).
+// Undocumented pairings (e.g. `input[type=checkbox] role=radio`) are NOT
+// exempted.
+const NATIVELY_CHECKED_INPUT_ROLE_PAIRS = new Set([
+  'checkbox:checkbox',
+  'checkbox:switch',
+  'checkbox:menuitemcheckbox',
+  'radio:radio',
+  'radio:menuitemradio',
 ]);
 
 function getInputType(node) {
@@ -46,17 +48,18 @@ function getInputType(node) {
   }
   const typeAttr = node.attributes?.find((a) => a.name === 'type');
   if (typeAttr?.value?.type === 'GlimmerTextNode') {
-    return typeAttr.value.chars;
+    // HTML input `type` keywords are ASCII case-insensitive.
+    return typeAttr.value.chars?.toLowerCase();
   }
   return undefined;
 }
 
 function isNativelyChecked(node, role) {
-  if (!ROLES_WITH_IMPLICIT_CHECKED_FROM_INPUT.has(role)) {
+  const type = getInputType(node);
+  if (!type) {
     return false;
   }
-  const type = getInputType(node);
-  return type === 'checkbox' || type === 'radio';
+  return NATIVELY_CHECKED_INPUT_ROLE_PAIRS.has(`${type}:${role}`);
 }
 
 function getMissingRequiredAttributes(role, foundAriaAttributes, node) {

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

@@ -34,6 +34,9 @@ ruleTester.run('template-require-mandatory-role-attributes', rule, {
     '<template><input type="radio" role="menuitemradio" /></template>',
     '<template><input type="radio" role="radio" /></template>',
     '<template><input type="checkbox" role="checkbox" /></template>',
+
+    // HTML `type` is ASCII case-insensitive; `Checkbox` must match `checkbox`.
+    '<template><input type="Checkbox" role="switch" /></template>',
   ],
 
   invalid: [
@@ -84,6 +87,34 @@ ruleTester.run('template-require-mandatory-role-attributes', rule, {
       output: null,
       errors: [{ message: 'The attribute aria-checked is required by the role checkbox' }],
     },
+
+    // Undocumented {input type, role} pairings are NOT exempted.
+    {
+      code: '<template><input type="checkbox" role="radio" /></template>',
+      output: null,
+      errors: [{ message: 'The attribute aria-checked is required by the role radio' }],
+    },
+    {
+      code: '<template><input type="radio" role="switch" /></template>',
+      output: null,
+      errors: [{ message: 'The attribute aria-checked is required by the role switch' }],
+    },
+    {
+      code: '<template><input type="radio" role="checkbox" /></template>',
+      output: null,
+      errors: [{ message: 'The attribute aria-checked is required by the role checkbox' }],
+    },
+    {
+      code: '<template><input type="text" role="switch" /></template>',
+      output: null,
+      errors: [{ message: 'The attribute aria-checked is required by the role switch' }],
+    },
+    {
+      // No `type` attribute; defaults to text.
+      code: '<template><input role="switch" /></template>',
+      output: null,
+      errors: [{ message: 'The attribute aria-checked is required by the role switch' }],
+    },
   ],
 });
 
@@ -121,6 +152,9 @@ hbsRuleTester.run('template-require-mandatory-role-attributes', rule, {
     '<input type="radio" role="menuitemradio" />',
     '<input type="radio" role="radio" />',
     '<input type="checkbox" role="checkbox" />',
+
+    // HTML `type` is ASCII case-insensitive; `Checkbox` must match `checkbox`.
+    '<input type="Checkbox" role="switch" />',
   ],
   invalid: [
     {
@@ -162,5 +196,33 @@ hbsRuleTester.run('template-require-mandatory-role-attributes', rule, {
       output: null,
       errors: [{ message: 'The attribute aria-checked is required by the role checkbox' }],
     },
+
+    // Undocumented {input type, role} pairings are NOT exempted.
+    {
+      code: '<input type="checkbox" role="radio" />',
+      output: null,
+      errors: [{ message: 'The attribute aria-checked is required by the role radio' }],
+    },
+    {
+      code: '<input type="radio" role="switch" />',
+      output: null,
+      errors: [{ message: 'The attribute aria-checked is required by the role switch' }],
+    },
+    {
+      code: '<input type="radio" role="checkbox" />',
+      output: null,
+      errors: [{ message: 'The attribute aria-checked is required by the role checkbox' }],
+    },
+    {
+      code: '<input type="text" role="switch" />',
+      output: null,
+      errors: [{ message: 'The attribute aria-checked is required by the role switch' }],
+    },
+    {
+      // No `type` attribute; defaults to text.
+      code: '<input role="switch" />',
+      output: null,
+      errors: [{ message: 'The attribute aria-checked is required by the role switch' }],
+    },
   ],
 });