Double-invoke first function component render too

Author: gaearon

packages/react-art/src/__tests__/ReactART-test.js

@@ -385,7 +385,7 @@ describe('ReactART', () => {
       </CurrentRendererContext.Provider>,
     );
 
-    ReactNoop.flushThrough(['A']);
+    ReactNoop.flushThrough(__DEV__ ? ['A', 'A'] : ['A']);
 
     ReactDOM.render(
       <Surface>
@@ -400,7 +400,9 @@ describe('ReactART', () => {
     expect(ops).toEqual([null, 'ART']);
 
     ops = [];
-    expect(ReactNoop.flush()).toEqual(['B', 'C']);
+    expect(ReactNoop.flush()).toEqual(
+      __DEV__ ? ['B', 'B', 'C', 'C'] : ['B', 'C'],
+    );
 
     expect(ops).toEqual(['Test']);
   });

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

@@ -232,7 +232,7 @@ describe('ReactDOMRoot', () => {
     // Flush all async work.
     jest.runAllTimers();
     // Root should complete without committing.
-    expect(ops).toEqual(['Foo']);
+    expect(ops).toEqual(__DEV__ ? ['Foo', 'Foo'] : ['Foo']);
     expect(container.textContent).toEqual('');
 
     ops = [];

packages/react-reconciler/src/ReactFiberBeginWork.js

@@ -1173,7 +1173,20 @@ function mountIndeterminateComponent(
       context,
       renderExpirationTime,
     );
-    // TODO: double-render here in strict mode.
+    if (
+      debugRenderPhaseSideEffects ||
+      (debugRenderPhaseSideEffectsForStrictMode &&
+        workInProgress.mode & StrictMode)
+    ) {
+      renderWithHooks(
+        null,
+        workInProgress,
+        Component,
+        props,
+        context,
+        renderExpirationTime,
+      );
+    }
   } else {
     value = renderWithHooks(
       null,

packages/react-reconciler/src/__tests__/ErrorBoundaryReconciliation-test.internal.js

@@ -70,7 +70,11 @@ describe('ErrorBoundaryReconciliation', () => {
         if (isConcurrent) {
           renderer.unstable_flushAll();
         }
-      }).toWarnDev(isConcurrent ? ['invalid', 'invalid', 'invalid', 'invalid'] : ['invalid']);
+      }).toWarnDev(
+        isConcurrent
+          ? ['invalid', 'invalid', 'invalid', 'invalid']
+          : ['invalid'],
+      );
       const Fallback = fallbackTagName;
       expect(renderer).toMatchRenderedOutput(<Fallback prop="ErrorBoundary" />);
     }

packages/react-test-renderer/src/__tests__/ReactTestRendererAsync-test.js

@@ -62,18 +62,19 @@ describe('ReactTestRendererAsync', () => {
       unstable_isConcurrent: true,
     });
 
-    expect(renderer).toFlushAndYield(['A:1', 'B:1', 'C:1']);
+    expect(renderer).toFlushAndYield(
+      __DEV__
+        ? ['A:1', 'A:1', 'B:1', 'B:1', 'C:1', 'C:1']
+        : ['A:1', 'B:1', 'C:1'],
+    );
     expect(renderer.toJSON()).toEqual(['A:1', 'B:1', 'C:1']);
 
     renderer.update(<Parent step={2} />);
-    expect(renderer).toFlushAndYield(__DEV__ ? [
-      'A:2',
-      'A:2',
-      'B:2',
-      'B:2',
-      'C:2',
-      'C:2'
-    ] : ['A:2', 'B:2', 'C:2']);
+    expect(renderer).toFlushAndYield(
+      __DEV__
+        ? ['A:2', 'A:2', 'B:2', 'B:2', 'C:2', 'C:2']
+        : ['A:2', 'B:2', 'C:2'],
+    );
     expect(renderer.toJSON()).toEqual(['A:2', 'B:2', 'C:2']);
   });
 
@@ -96,12 +97,14 @@ describe('ReactTestRendererAsync', () => {
     });
 
     // Flush the first two siblings
-    expect(renderer).toFlushAndYieldThrough(['A:1', 'B:1']);
+    expect(renderer).toFlushAndYieldThrough(
+      __DEV__ ? ['A:1', 'A:1', 'B:1', 'B:1'] : ['A:1', 'B:1'],
+    );
     // Did not commit yet.
     expect(renderer.toJSON()).toEqual(null);
 
     // Flush the remaining work
-    expect(renderer).toFlushAndYield(['C:1']);
+    expect(renderer).toFlushAndYield(__DEV__ ? ['C:1', 'C:1'] : ['C:1']);
     expect(renderer.toJSON()).toEqual(['A:1', 'B:1', 'C:1']);
   });
 
@@ -133,7 +136,7 @@ describe('ReactTestRendererAsync', () => {
     });
 
     // Flush the some of the changes, but don't commit
-    expect(renderer).toFlushAndYieldThrough(['A:1']);
+    expect(renderer).toFlushAndYieldThrough(__DEV__ ? ['A:1', 'A:1'] : ['A:1']);
     expect(renderer.toJSON()).toEqual(null);
 
     // Interrupt with higher priority properties
@@ -229,30 +232,54 @@ describe('ReactTestRendererAsync', () => {
       });
 
       expect(renderer).toFlushAndThrow('Oh no!');
-      expect(ReactTestRenderer).toHaveYielded([
-        'A',
-        'B',
-        'C',
-        'D',
-        'A',
-        'B',
-        'C',
-        'D',
-      ]);
+      expect(ReactTestRenderer).toHaveYielded(
+        __DEV__
+          ? [
+              'A',
+              'A',
+              'B',
+              'B',
+              'C',
+              'C',
+              'D',
+              'D',
+              'A',
+              'A',
+              'B',
+              'B',
+              'C',
+              'C',
+              'D',
+              'D',
+            ]
+          : ['A', 'B', 'C', 'D', 'A', 'B', 'C', 'D'],
+      );
 
       renderer.update(<App />);
 
       expect(renderer).toFlushAndThrow('Oh no!');
-      expect(ReactTestRenderer).toHaveYielded([
-        'A',
-        'B',
-        'C',
-        'D',
-        'A',
-        'B',
-        'C',
-        'D',
-      ]);
+      expect(ReactTestRenderer).toHaveYielded(
+        __DEV__
+          ? [
+              'A',
+              'A',
+              'B',
+              'B',
+              'C',
+              'C',
+              'D',
+              'D',
+              'A',
+              'A',
+              'B',
+              'B',
+              'C',
+              'C',
+              'D',
+              'D',
+            ]
+          : ['A', 'B', 'C', 'D', 'A', 'B', 'C', 'D'],
+      );
 
       renderer.update(<App />);
       expect(renderer).toFlushAndThrow('Oh no!');