Fix stack traces when using EntityPersistExecutor

[bogdan]

Description of change

Floating promises are causing issues with lost stack traces. Summary of a change:

+        await Promise.resolve();
+       // do whatever
-        return Promise.resolve().then(async () => {
-          // do whatever
-       });

This hack was added in a4e5abe and related tests are passing.

Example

Old stack trace in my app:

     ObjectInvalid: An instance of Domain has failed the validation:
      at Domain.validateOrReject (lib/entities/Model.ts:171:13)

New stack trace in my app:

     ObjectInvalid: An instance of Domain has failed the validation:
      at Domain.validateOrReject (lib/entities/Model.ts:171:13)
      at Domain.captureStack (lib/entities/Model.ts:163:19)
      at EntityListenerMetadata.execute (src/metadata/EntityListenerMetadata.ts:71:45)
      at /Users/bogdan/makabu/unstoppable/unstoppable-domains-website/default/src/subscriber/Broadcaster.ts:38:54
      at Array.forEach (<anonymous>)
      at Broadcaster.broadcastBeforeInsertEvent (src/subscriber/Broadcaster.ts:36:44)
      at /Users/bogdan/makabu/unstoppable/unstoppable-domains-website/default/src/persistence/SubjectExecutor.ts:210:81
      at Array.forEach (<anonymous>)
      at SubjectExecutor.broadcastBeforeEventsForAll (src/persistence/SubjectExecutor.ts:210:33)
      at SubjectExecutor.<anonymous> (src/persistence/SubjectExecutor.ts:107:38)
      at step (node_modules/typeorm/node_modules/tslib/tslib.js:141:27)
      at Object.next (node_modules/typeorm/node_modules/tslib/tslib.js:122:57)
      at /Users/bogdan/makabu/unstoppable/unstoppable-domains-website/default/node_modules/typeorm/node_modules/tslib/tslib.js:115:75
      at new Promise (<anonymous>)
      at Object.__awaiter (node_modules/typeorm/node_modules/tslib/tslib.js:111:16)
      at SubjectExecutor.execute (node_modules/typeorm/persistence/SubjectExecutor.js:67:24)
      at EntityPersistExecutor_1.EntityPersistExecutor.execute (lib/connect.ts:226:26)
      at processTicksAndRejections (internal/process/task_queues.js:97:5)
      at Context.<anonymous> (lib/entities/Model.test.ts:20:5)

I was trying to make a test for an error stack to be full, but unfortunately it is only testable when typescript compiler option is set to es2018 or above. Your target is es5 which is too low for it even to be testable.

Pull-Request Checklist

• Code is up-to-date with the master branch
• npm run lint passes with this change
• npm run test passes with this change
• There are new or updated unit tests validating the change
• Documentation has been updated to reflect this change
• The new commits follow conventions explained in CONTRIBUTING.md

[nebkat]

Looks good, if you can just add fix: in front of the commit title as per CONTRIBUTING.md.

[pleerock]

Thank you for contribution! 🎉