fix: docs limitations note, correct exemption count, static mustache names, type default, array includes

Author: johanrd

docs/rules/template-no-duplicate-form-names.md

@@ -10,7 +10,7 @@ Duplicate names break form serialization: both values are emitted into
 the entry list, and server-side code that expects a single value typically
 reads only one — often not the one the author intended.
 
-Two categories are exempt from the duplicate check:
+Three categories are exempt from the duplicate check:
 
 - **Non-submitting controls** (`<input type="button">`, `<input type="reset">`,
   `<button type="button">`, `<button type="reset">`) are skipped entirely.
@@ -64,6 +64,9 @@ real collision.
 
 ## Limitations
 
+- Controls associated with a form via the `form="id"` attribute (rather than
+  by nesting inside a `<form>` element) are not tracked by this rule. Only
+  controls that are descendants of a `<form>` element are scoped to that form.
 - `name` values via mustache (`name={{this.fieldName}}`) are skipped — we
   cannot know the value at lint time.
 - The `name[]` PHP-style array pattern is treated as an ordinary name; if

lib/rules/template-no-duplicate-form-names.js

@@ -41,7 +41,7 @@ function buildSubmitLikeInputTypes() {
     if (schema.name !== 'input') {
       continue;
     }
-    if (![...rolesSet].includes('button')) {
+    if (!rolesSet.includes('button')) {
       continue;
     }
     const typeAttr = (schema.attributes || []).find((a) => a.name === 'type');
@@ -90,6 +90,17 @@ function getStaticAttrValue(node, name) {
   if (attr.value.type === 'GlimmerTextNode') {
     return { kind: 'static', value: attr.value.chars };
   }
+  if (
+    attr.value.type === 'GlimmerMustacheStatement' &&
+    attr.value.path
+  ) {
+    if (attr.value.path.type === 'GlimmerStringLiteral') {
+      return { kind: 'static', value: attr.value.path.value };
+    }
+    if (attr.value.path.type === 'GlimmerBooleanLiteral') {
+      return { kind: 'static', value: String(attr.value.path.value) };
+    }
+  }
   return { kind: 'dynamic', value: '' };
 }
 
@@ -140,7 +151,7 @@ function getControlType(node) {
     if (t.kind === 'static') {
       return INPUT_TYPES.has(t.value.toLowerCase()) ? t.value.toLowerCase() : 'text';
     }
-    if (t.kind === 'absent') {
+    if (t.kind === 'absent' || t.kind === 'empty') {
       return 'text';
     }
     return 'unknown';