Revert "Always skip unmounted/unmounting error boundaries"

This commit reverts bcca5a6, although it that commit DOES NOT revert cleanly. This revert was largely manual.

Author: Brian Vaughn

packages/react-dom/src/__tests__/ReactErrorBoundaries-test.internal.js

@@ -2473,175 +2473,4 @@ describe('ReactErrorBoundaries', () => {
       'Caught an error: gotta catch em all.',
     );
   });
-
-  // @gate skipUnmountedBoundaries
-  it('catches errors thrown in componentWillUnmount', () => {
-    class LocalErrorBoundary extends React.Component {
-      state = {error: null};
-      static getDerivedStateFromError(error) {
-        Scheduler.unstable_yieldValue(
-          `ErrorBoundary static getDerivedStateFromError`,
-        );
-        return {error};
-      }
-      render() {
-        const {children, id, fallbackID} = this.props;
-        const {error} = this.state;
-        if (error) {
-          Scheduler.unstable_yieldValue(`${id} render error`);
-          return <Component id={fallbackID} />;
-        }
-        Scheduler.unstable_yieldValue(`${id} render success`);
-        return children || null;
-      }
-    }
-
-    class Component extends React.Component {
-      render() {
-        const {id} = this.props;
-        Scheduler.unstable_yieldValue('Component render ' + id);
-        return id;
-      }
-    }
-
-    class LocalBrokenComponentWillUnmount extends React.Component {
-      componentWillUnmount() {
-        Scheduler.unstable_yieldValue(
-          'BrokenComponentWillUnmount componentWillUnmount',
-        );
-        throw Error('Expected');
-      }
-
-      render() {
-        Scheduler.unstable_yieldValue('BrokenComponentWillUnmount render');
-        return 'broken';
-      }
-    }
-
-    const container = document.createElement('div');
-
-    ReactDOM.render(
-      <LocalErrorBoundary id="OuterBoundary" fallbackID="OuterFallback">
-        <Component id="sibling" />
-        <LocalErrorBoundary id="InnerBoundary" fallbackID="InnerFallback">
-          <LocalBrokenComponentWillUnmount />
-        </LocalErrorBoundary>
-      </LocalErrorBoundary>,
-      container,
-    );
-
-    expect(container.firstChild.textContent).toBe('sibling');
-    expect(container.lastChild.textContent).toBe('broken');
-    expect(Scheduler).toHaveYielded([
-      'OuterBoundary render success',
-      'Component render sibling',
-      'InnerBoundary render success',
-      'BrokenComponentWillUnmount render',
-    ]);
-
-    ReactDOM.render(
-      <LocalErrorBoundary id="OuterBoundary" fallbackID="OuterFallback">
-        <Component id="sibling" />
-      </LocalErrorBoundary>,
-      container,
-    );
-
-    // React should skip over the unmounting boundary and find the nearest still-mounted boundary.
-    expect(container.firstChild.textContent).toBe('OuterFallback');
-    expect(container.lastChild.textContent).toBe('OuterFallback');
-    expect(Scheduler).toHaveYielded([
-      'OuterBoundary render success',
-      'Component render sibling',
-      'BrokenComponentWillUnmount componentWillUnmount',
-      'ErrorBoundary static getDerivedStateFromError',
-      'OuterBoundary render error',
-      'Component render OuterFallback',
-    ]);
-  });
-
-  // @gate skipUnmountedBoundaries
-  it('catches errors thrown while detaching refs', () => {
-    class LocalErrorBoundary extends React.Component {
-      state = {error: null};
-      static getDerivedStateFromError(error) {
-        Scheduler.unstable_yieldValue(
-          `ErrorBoundary static getDerivedStateFromError`,
-        );
-        return {error};
-      }
-      render() {
-        const {children, id, fallbackID} = this.props;
-        const {error} = this.state;
-        if (error) {
-          Scheduler.unstable_yieldValue(`${id} render error`);
-          return <Component id={fallbackID} />;
-        }
-        Scheduler.unstable_yieldValue(`${id} render success`);
-        return children || null;
-      }
-    }
-
-    class Component extends React.Component {
-      render() {
-        const {id} = this.props;
-        Scheduler.unstable_yieldValue('Component render ' + id);
-        return id;
-      }
-    }
-
-    class LocalBrokenCallbackRef extends React.Component {
-      _ref = ref => {
-        Scheduler.unstable_yieldValue('LocalBrokenCallbackRef ref ' + !!ref);
-        if (ref === null) {
-          throw Error('Expected');
-        }
-      };
-
-      render() {
-        Scheduler.unstable_yieldValue('LocalBrokenCallbackRef render');
-        return <div ref={this._ref}>ref</div>;
-      }
-    }
-
-    const container = document.createElement('div');
-
-    ReactDOM.render(
-      <LocalErrorBoundary id="OuterBoundary" fallbackID="OuterFallback">
-        <Component id="sibling" />
-        <LocalErrorBoundary id="InnerBoundary" fallbackID="InnerFallback">
-          <LocalBrokenCallbackRef />
-        </LocalErrorBoundary>
-      </LocalErrorBoundary>,
-      container,
-    );
-
-    expect(container.firstChild.textContent).toBe('sibling');
-    expect(container.lastChild.textContent).toBe('ref');
-    expect(Scheduler).toHaveYielded([
-      'OuterBoundary render success',
-      'Component render sibling',
-      'InnerBoundary render success',
-      'LocalBrokenCallbackRef render',
-      'LocalBrokenCallbackRef ref true',
-    ]);
-
-    ReactDOM.render(
-      <LocalErrorBoundary id="OuterBoundary" fallbackID="OuterFallback">
-        <Component id="sibling" />
-      </LocalErrorBoundary>,
-      container,
-    );
-
-    // React should skip over the unmounting boundary and find the nearest still-mounted boundary.
-    expect(container.firstChild.textContent).toBe('OuterFallback');
-    expect(container.lastChild.textContent).toBe('OuterFallback');
-    expect(Scheduler).toHaveYielded([
-      'OuterBoundary render success',
-      'Component render sibling',
-      'LocalBrokenCallbackRef ref false',
-      'ErrorBoundary static getDerivedStateFromError',
-      'OuterBoundary render error',
-      'Component render OuterFallback',
-    ]);
-  });
 });