fix(noVueDuplicateKeys): fix false positives when keys are defined in watch

.changeset/quick-hands-show.md

@@ -0,0 +1,5 @@
+---
+"@biomejs/biome": patch
+---
+
+Fixed [#9250](https://github.com/biomejs/biome/issues/9250): `noVueDuplicateKeys` will no longer flag keys under `watch`, preventing false positives.

crates/biome_js_analyze/src/lint/correctness/no_vue_duplicate_keys.rs

@@ -138,7 +138,9 @@ impl Rule for NoVueDuplicateKeys {
         let mut key_declarations: FxHashMap<String, Vec<VueDeclaration>> = FxHashMap::default();
 
         // Collect all declarations across all Vue component sections
-        for declaration in component.declarations(VueDeclarationCollectionFilter::all()) {
+        for declaration in component.declarations(
+            VueDeclarationCollectionFilter::all() ^ VueDeclarationCollectionFilter::Watcher,
+        ) {
             if let Some(name) = declaration.declaration_name() {
                 // Handle cases like `const { foo } = defineProps(...);`.
                 if let VueDeclaration::Setup(ref setup_decl) = declaration

crates/biome_js_analyze/tests/specs/correctness/noVueDuplicateKeys/valid-watch.vue

@@ -0,0 +1,25 @@
+<template>
+  <div>This is valid because this is how you declare watchers in Vue. The child keys of `watch` define which properties/variables to watch, and they are not declarations.</div>
+</template>
+
+<script>
+	export default {
+		name: 'QFormContainer',
+		props: {
+			formData: {
+				type: Object,
+				default: () => ({}),
+				validator: (val) => true
+			},
+		},
+		watch: {
+			formData: {
+				handler(newValue)
+				{
+					//do things
+				},
+				deep: true
+			}
+		}
+	}
+</script>

crates/biome_js_analyze/tests/specs/correctness/noVueDuplicateKeys/valid-watch.vue.snap

@@ -0,0 +1,27 @@
+---
+source: crates/biome_js_analyze/tests/spec_tests.rs
+expression: valid-watch.vue
+---
+# Input
+```ts
+	export default {
+		name: 'QFormContainer',
+		props: {
+			formData: {
+				type: Object,
+				default: () => ({}),
+				validator: (val) => true
+			},
+		},
+		watch: {
+			formData: {
+				handler(newValue)
+				{
+					//do things
+				},
+				deep: true
+			}
+		}
+	}
+
+```