fix: Select with `` value (#1207)

* Revert "fix: use strict null/undefined check for display value in single select (#1205)"

This reverts commit f781118.

* fix: check displayValue label before adding -content-has-value className

Ensures the -content-has-value className is only added when displayValue has a truthy label property, preventing the class from being added when value is empty or null.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: zombieJ

src/SelectInput/Content/SingleContent.tsx

@@ -88,7 +88,7 @@ const SingleContent = React.forwardRef<HTMLInputElement, SharedContentProps>(
       <div
         className={clsx(
           `${prefixCls}-content`,
-          displayValue && `${prefixCls}-content-has-value`,
+          displayValue && displayValue.label && `${prefixCls}-content-has-value`,
           mergedSearchValue && `${prefixCls}-content-has-search-value`,
           hasOptionStyle && `${prefixCls}-content-has-option-style`,
           classNames?.content,

tests/Select.test.tsx

@@ -273,6 +273,15 @@ describe('Select.Basic', () => {
     expect(container.querySelector('.rc-select-content-has-option-style')).toBeTruthy();
   });
 
+  it('should not add -content-has-value className when value is empty string', () => {
+    const { container } = render(
+      <Select value="">
+        <Option value="1">One</Option>
+      </Select>,
+    );
+    expect(container.querySelector('.rc-select-content-has-value')).toBeFalsy();
+  });
+
   it('should default select the right option', () => {
     const { container } = render(
       <Select defaultValue="2">