apollo-server-core: properly re-throw serverWillStop exceptions

If a `serverWillStop` callback invoked by `server.stop()` throws (or
`gateway.stop()`), then `server.stop()` now correctly throws that error
instead of returning.

This was a regression introduced in Apollo Server v2.22.0. (Between
v2.22 and this release, a second subsequent or concurrent call to
`server.stop()` would correctly throw the error, but not the original
call.)

Fixes #5649.

CHANGELOG.md

@@ -9,6 +9,10 @@ The version headers in this history reflect the versions of Apollo Server itself
 
 ## vNEXT
 
+## v3.3.0
+
+- `apollo-server-core`: If a `serverWillStop` callback invoked by `server.stop()` throws (or `gateway.stop()`), then `server.stop()` now correctly throws that error instead of returning. This was a regression introduced in Apollo Server v2.22.0. (Between v2.22 and this release, a second subsequent or concurrent call to `server.stop()` would correctly throw the error, but not the original call.) [Issue #5649](https://github.com/apollographql/apollo-server/issues/5649) [PR #5653](https://github.com/apollographql/apollo-server/pull/5653)
+
 ## v3.2.0
 
 **If you're using `apollo-server-express` or another framework integration**, we highly recommend that you enable the new graceful shutdown feature after upgrading to 3.2.0. See the docs for [`ApolloServerPluginDrainHttpServer`](https://www.apollographql.com/docs/apollo-server/api/plugin/drain-http-server/) or the [basic usage for your integration of choice](https://www.apollographql.com/docs/apollo-server/integrations/middleware/#basic-usage).

packages/apollo-server-core/src/ApolloServer.ts

@@ -745,7 +745,7 @@ export class ApolloServerBase<
       await Promise.all([...this.toDisposeLast].map((dispose) => dispose()));
     } catch (stopError) {
       this.state = { phase: 'stopped', stopError };
-      return;
+      throw stopError;
     }
     this.state = { phase: 'stopped', stopError: null };
   }