Invoke both legacy and UNSAFE_ lifecycles when both are present (#12134)

* Invoke both legacy and UNSAFE_ lifecycles when both are present

This is to support edge cases with eg create-react-class where a mixin defines a legacy lifecycle but the component being created defines an UNSAFE one (or vice versa).

I did not warn about this case because the warning would be a bit redundant with the deprecation warning which we will soon be enabling. I could be convinced to change my stance here though.

* Added explicit function-type check to SS ReactPartialRenderer

Author: bvaughn

src/ReactShallowRenderer.js

@@ -209,7 +209,11 @@ class ReactShallowRenderer {
         if (typeof element.type.getDerivedStateFromProps !== 'function') {
           this._instance.componentWillMount();
         }
-      } else if (typeof element.type.getDerivedStateFromProps !== 'function') {
+      }
+      if (
+        typeof this._instance.UNSAFE_componentWillMount === 'function' &&
+        typeof element.type.getDerivedStateFromProps !== 'function'
+      ) {
         // In order to support react-lifecycles-compat polyfilled components,
         // Unsafe lifecycles should not be invoked for any component with the new gDSFP.
         this._instance.UNSAFE_componentWillMount();
@@ -259,7 +263,8 @@ class ReactShallowRenderer {
         if (typeof element.type.getDerivedStateFromProps !== 'function') {
           this._instance.componentWillReceiveProps(props, context);
         }
-      } else if (
+      }
+      if (
         typeof this._instance.UNSAFE_componentWillReceiveProps === 'function' &&
         typeof element.type.getDerivedStateFromProps !== 'function'
       ) {
@@ -316,7 +321,8 @@ class ReactShallowRenderer {
         if (typeof type.getDerivedStateFromProps !== 'function') {
           this._instance.componentWillUpdate(props, state, context);
         }
-      } else if (
+      }
+      if (
         typeof this._instance.UNSAFE_componentWillUpdate === 'function' &&
         typeof type.getDerivedStateFromProps !== 'function'
       ) {

src/__tests__/ReactShallowRenderer-test.js

@@ -1235,4 +1235,46 @@ describe('ReactShallowRenderer', () => {
     // De-duped
     shallowRenderer.render(<Component />);
   });
+
+  it('should invoke both deprecated and new lifecycles if both are present', () => {
+    const log = [];
+
+    class Component extends React.Component {
+      componentWillMount() {
+        log.push('componentWillMount');
+      }
+      componentWillReceiveProps() {
+        log.push('componentWillReceiveProps');
+      }
+      componentWillUpdate() {
+        log.push('componentWillUpdate');
+      }
+      UNSAFE_componentWillMount() {
+        log.push('UNSAFE_componentWillMount');
+      }
+      UNSAFE_componentWillReceiveProps() {
+        log.push('UNSAFE_componentWillReceiveProps');
+      }
+      UNSAFE_componentWillUpdate() {
+        log.push('UNSAFE_componentWillUpdate');
+      }
+      render() {
+        return null;
+      }
+    }
+
+    const shallowRenderer = createRenderer();
+    shallowRenderer.render(<Component foo="bar" />);
+    expect(log).toEqual(['componentWillMount', 'UNSAFE_componentWillMount']);
+
+    log.length = 0;
+
+    shallowRenderer.render(<Component foo="baz" />);
+    expect(log).toEqual([
+      'componentWillReceiveProps',
+      'UNSAFE_componentWillReceiveProps',
+      'componentWillUpdate',
+      'UNSAFE_componentWillUpdate',
+    ]);
+  });
 });