fix: incorrect display when value is null in multiple mode (#1009)

* fix: incorrect display when value is null in multiple mode

* test: optimize case

Author: madocto

src/Select.tsx

@@ -311,15 +311,16 @@ const Select = React.forwardRef(
 
     // Merged value with LabelValueType
     const rawLabeledValues = React.useMemo(() => {
-      const values = convert2LabelValues(internalValue);
+      const newInternalValue = multiple && internalValue === null ? [] : internalValue;
+      const values = convert2LabelValues(newInternalValue);
 
       // combobox no need save value when it's no value (exclude value equal 0)
       if (mode === 'combobox' && isComboNoValue(values[0]?.value)) {
         return [];
       }
 
       return values;
-    }, [internalValue, convert2LabelValues, mode]);
+    }, [internalValue, convert2LabelValues, mode, multiple]);
 
     // Fill label with cache to avoid option remove
     const [mergedValues, getMixedOption] = useCache(rawLabeledValues, valueOptions);

tests/Multiple.test.tsx

@@ -546,6 +546,24 @@ describe('Select.Multiple', () => {
     expect(wrapper.find('Selector').props().values.length).toEqual(0);
   });
 
+  it('display correctly when value is undefined or null', () => {
+    const wrapper1 = mount(
+      <Select mode="multiple" value={undefined}>
+        <Option value={1}>1</Option>
+        <Option value={2}>2</Option>
+      </Select>,
+    );
+    const wrapper2 = mount(
+      <Select mode="multiple" value={null}>
+        <Option value={1}>1</Option>
+        <Option value={2}>2</Option>
+      </Select>,
+    );
+
+    expect(wrapper1.find('.rc-select-selection-item').length).toBe(0);
+    expect(wrapper2.find('.rc-select-selection-item').length).toBe(0);
+  });
+
   describe('optionLabelProp', () => {
     it('basic', () => {
       const wrapper = mount(