Ignore option callbacks when deciding to update a query

CHANGELOG.md

@@ -5,6 +5,9 @@
 - Rework interdependencies between `@apollo/client/*` entry points, so that CommonJS and ESM modules are supported equally well, without any duplication of shared code. <br/>
   [@benjamn](https://github.com/benjamn) in [#6058](https://github.com/apollographql/apollo-client/pull/6058)
 
+- Tolerate `!==` callback functions (like `onCompleted` and `onError`) in `useQuery` options, since those functions are almost always freshly evaluated each time `useQuery` is called. <br/>
+  [@hwillson](https://github.com/hwillson) and [@benjamn](https://github.com/benjamn) in [#6588](https://github.com/apollographql/apollo-client/pull/6588)
+
 ## Apollo Client 3.0.2
 
 ## Bug Fixes

package.json

@@ -67,7 +67,7 @@
   "dependencies": {
     "@types/zen-observable": "^0.8.0",
     "@wry/context": "^0.5.2",
-    "@wry/equality": "^0.1.9",
+    "@wry/equality": "^0.2.0",
     "fast-json-stable-stringify": "^2.0.0",
     "graphql-tag": "^2.10.4",
     "hoist-non-react-statics": "^3.3.2",

src/react/hooks/__tests__/useQuery.test.tsx

@@ -1814,6 +1814,43 @@ describe('useQuery Hook', () => {
 
       return wait().then(resolve, reject);
     });
+
+    itAsync(
+      'should not make extra network requests when `onCompleted` is ' +
+      'defined with a `network-only` fetch policy',
+      (resolve, reject) => {
+        let renderCount = 0;
+        function Component() {
+          const { loading, data } = useQuery(CAR_QUERY, {
+            fetchPolicy: 'network-only',
+            onCompleted: () => undefined
+          });
+          switch (++renderCount) {
+            case 1:
+              expect(loading).toBeTruthy();
+              break;
+            case 2:
+              expect(loading).toBeFalsy();
+              expect(data).toEqual(CAR_RESULT_DATA);
+              break;
+            case 3:
+              fail('Too many renders');
+            default:
+          }
+          return null;
+        }
+
+        render(
+          <MockedProvider mocks={CAR_MOCKS}>
+            <Component />
+          </MockedProvider>
+        );
+
+        return wait(() => {
+          expect(renderCount).toBe(2);
+        }).then(resolve, reject);
+      }
+    );
   });
 
   describe('Optimistic data', () => {