Fix hydration of non-string dangerousSetInnerHTML.__html

packages/react-dom/src/__tests__/ReactDOMServerIntegrationElements-test.js

@@ -485,16 +485,97 @@ describe('ReactDOMServerIntegration', () => {
       expect(e.tagName).toBe('BUTTON');
     });
 
-    itRenders('a div with dangerouslySetInnerHTML', async render => {
-      const e = await render(
-        <div dangerouslySetInnerHTML={{__html: "<span id='child'/>"}} />,
-      );
+    itRenders('a div with dangerouslySetInnerHTML number', async render => {
+      // Put dangerouslySetInnerHTML one level deeper because otherwise
+      // hydrating from a bad markup would cause a mismatch (since we don't
+      // patch dangerouslySetInnerHTML as text content).
+      const e = (await render(
+        <div>
+          <span dangerouslySetInnerHTML={{__html: 0}} />
+        </div>,
+      )).firstChild;
+      expect(e.childNodes.length).toBe(1);
+      expect(e.firstChild.nodeType).toBe(TEXT_NODE_TYPE);
+      expect(e.textContent).toBe('0');
+    });
+
+    itRenders('a div with dangerouslySetInnerHTML boolean', async render => {
+      // Put dangerouslySetInnerHTML one level deeper because otherwise
+      // hydrating from a bad markup would cause a mismatch (since we don't
+      // patch dangerouslySetInnerHTML as text content).
+      const e = (await render(
+        <div>
+          <span dangerouslySetInnerHTML={{__html: false}} />
+        </div>,
+      )).firstChild;
+      expect(e.childNodes.length).toBe(1);
+      expect(e.firstChild.nodeType).toBe(TEXT_NODE_TYPE);
+      expect(e.firstChild.data).toBe('false');
+    });
+
+    itRenders(
+      'a div with dangerouslySetInnerHTML text string',
+      async render => {
+        // Put dangerouslySetInnerHTML one level deeper because otherwise
+        // hydrating from a bad markup would cause a mismatch (since we don't
+        // patch dangerouslySetInnerHTML as text content).
+        const e = (await render(
+          <div>
+            <span dangerouslySetInnerHTML={{__html: 'hello'}} />
+          </div>,
+        )).firstChild;
+        expect(e.childNodes.length).toBe(1);
+        expect(e.firstChild.nodeType).toBe(TEXT_NODE_TYPE);
+        expect(e.textContent).toBe('hello');
+      },
+    );
+
+    itRenders(
+      'a div with dangerouslySetInnerHTML element string',
+      async render => {
+        const e = await render(
+          <div dangerouslySetInnerHTML={{__html: "<span id='child'/>"}} />,
+        );
+        expect(e.childNodes.length).toBe(1);
+        expect(e.firstChild.tagName).toBe('SPAN');
+        expect(e.firstChild.getAttribute('id')).toBe('child');
+        expect(e.firstChild.childNodes.length).toBe(0);
+      },
+    );
+
+    itRenders('a div with dangerouslySetInnerHTML object', async render => {
+      const obj = {
+        toString() {
+          return "<span id='child'/>";
+        },
+      };
+      const e = await render(<div dangerouslySetInnerHTML={{__html: obj}} />);
       expect(e.childNodes.length).toBe(1);
       expect(e.firstChild.tagName).toBe('SPAN');
       expect(e.firstChild.getAttribute('id')).toBe('child');
       expect(e.firstChild.childNodes.length).toBe(0);
     });
 
+    itRenders(
+      'a div with dangerouslySetInnerHTML set to null',
+      async render => {
+        const e = await render(
+          <div dangerouslySetInnerHTML={{__html: null}} />,
+        );
+        expect(e.childNodes.length).toBe(0);
+      },
+    );
+
+    itRenders(
+      'a div with dangerouslySetInnerHTML set to undefined',
+      async render => {
+        const e = await render(
+          <div dangerouslySetInnerHTML={{__html: undefined}} />,
+        );
+        expect(e.childNodes.length).toBe(0);
+      },
+    );
+
     describe('newline-eating elements', function() {
       itRenders(
         'a newline-eating tag with content not starting with \\n',

packages/react-dom/src/__tests__/ReactDOMServerIntegrationReconnecting-test.js

@@ -412,6 +412,40 @@ describe('ReactDOMServerIntegration', () => {
         <div dangerouslySetInnerHTML={{__html: "<span id='child2'/>"}} />,
       ));
 
+    it('should error reconnecting a div with different text dangerouslySetInnerHTML', () =>
+      expectMarkupMismatch(
+        <div dangerouslySetInnerHTML={{__html: 'foo'}} />,
+        <div dangerouslySetInnerHTML={{__html: 'bar'}} />,
+      ));
+
+    it('should error reconnecting a div with different number dangerouslySetInnerHTML', () =>
+      expectMarkupMismatch(
+        <div dangerouslySetInnerHTML={{__html: 10}} />,
+        <div dangerouslySetInnerHTML={{__html: 20}} />,
+      ));
+
+    it('should error reconnecting a div with different object dangerouslySetInnerHTML', () =>
+      expectMarkupMismatch(
+        <div
+          dangerouslySetInnerHTML={{
+            __html: {
+              toString() {
+                return 'hi';
+              },
+            },
+          }}
+        />,
+        <div
+          dangerouslySetInnerHTML={{
+            __html: {
+              toString() {
+                return 'bye';
+              },
+            },
+          }}
+        />,
+      ));
+
     it('can explicitly ignore reconnecting a div with different dangerouslySetInnerHTML', () =>
       expectMarkupMatch(
         <div dangerouslySetInnerHTML={{__html: "<span id='child1'/>"}} />,

packages/react-dom/src/client/ReactDOMFiberComponent.js

@@ -987,9 +987,12 @@ export function diffHydratedProperties(
       ) {
         // Noop
       } else if (propKey === DANGEROUSLY_SET_INNER_HTML) {
-        const rawHtml = nextProp ? nextProp[HTML] || '' : '';
         const serverHTML = domElement.innerHTML;
-        const expectedHTML = normalizeHTML(domElement, rawHtml);
+        const nextHtml = nextProp ? nextProp[HTML] : undefined;
+        const expectedHTML = normalizeHTML(
+          domElement,
+          nextHtml != null ? nextHtml : '',
+        );
         if (expectedHTML !== serverHTML) {
           warnForPropDifference(propKey, serverHTML, expectedHTML);
         }

packages/react-dom/src/client/ReactDOMHostConfig.js

@@ -249,7 +249,7 @@ export function shouldSetTextContent(type: string, props: Props): boolean {
     typeof props.children === 'number' ||
     (typeof props.dangerouslySetInnerHTML === 'object' &&
       props.dangerouslySetInnerHTML !== null &&
-      typeof props.dangerouslySetInnerHTML.__html === 'string')
+      props.dangerouslySetInnerHTML.__html != null)
   );
 }