fix(require-default-prop): avoid requiring defaults for optional props not included in destructuring

.changeset/wise-bugs-peel.md

@@ -0,0 +1,5 @@
+---
+'eslint-plugin-vue': patch
+---
+
+[vue/require-default-prop](https://eslint.vuejs.org/rules/require-default-prop.html) now ignores optional props that are not included in Vue 3.5 props destructuring pattern.

lib/rules/require-default-prop.js

@@ -207,6 +207,19 @@ module.exports = {
               if (defaultsByWithDefaults[prop.propName]) {
                 return true
               }
+              // If using props destructure and this is an optional prop that is NOT included
+              // in the destructure pattern, exclude it from the report
+              if (
+                isUsingPropsDestructure &&
+                !prop.required &&
+                prop.propName != null
+              ) {
+                const destructuredProps = utils.getPropsDestructure(node)
+                if (!destructuredProps[prop.propName]) {
+                  // Optional prop is not destructured, so no default value is needed
+                  return true
+                }
+              }
             }
             if (!isUsingPropsDestructure) {
               return false

tests/lib/rules/require-default-prop.js

@@ -413,6 +413,40 @@ ruleTester.run('require-default-prop', rule, {
         ...languageOptions,
         parserOptions: { parser: require.resolve('@typescript-eslint/parser') }
       }
+    },
+    // Optional props that are not destructured should not require default values
+    {
+      filename: 'test.vue',
+      code: `
+      <script setup lang="ts">
+      const { bar } = defineProps<{
+        foo?: string;
+        bar: string;
+      }>()
+      </script>
+      `,
+      languageOptions: {
+        parser: require('vue-eslint-parser'),
+        ...languageOptions,
+        parserOptions: { parser: require.resolve('@typescript-eslint/parser') }
+      }
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script setup lang="ts">
+      const { bar } = defineProps<{
+        foo?: string;
+        bar: string;
+        baz?: number;
+      }>()
+      </script>
+      `,
+      languageOptions: {
+        parser: require('vue-eslint-parser'),
+        ...languageOptions,
+        parserOptions: { parser: require.resolve('@typescript-eslint/parser') }
+      }
     }
   ],
 
@@ -728,6 +762,7 @@ ruleTester.run('require-default-prop', rule, {
     },
     {
       // https://github.com/vuejs/eslint-plugin-vue/issues/2725
+      // Optional props that ARE destructured should still require default values
       filename: 'type-with-props-destructure.vue',
       code: `
       <script setup lang="ts">
@@ -745,6 +780,30 @@ ruleTester.run('require-default-prop', rule, {
           line: 3
         }
       ]
+    },
+    {
+      // Optional props that are NOT destructured should still cause errors if they are used in destructuring without defaults
+      filename: 'mixed-optional-destructure.vue',
+      code: `
+      <script setup lang="ts">
+      const {foo, bar, baz} = defineProps<{foo?: number; bar: number; baz?: string}>()
+      </script>
+      `,
+      languageOptions: {
+        parser: require('vue-eslint-parser'),
+        ...languageOptions,
+        parserOptions: { parser: require.resolve('@typescript-eslint/parser') }
+      },
+      errors: [
+        {
+          message: "Prop 'foo' requires default value to be set.",
+          line: 3
+        },
+        {
+          message: "Prop 'baz' requires default value to be set.",
+          line: 3
+        }
+      ]
     }
   ]
 })