Issue description

Subscribers with both 'beforeUpdate' and 'afterUpdate' methods defined cause duplicate 'updatedColumn' entries

Expected Behavior

When I define an event subscriber with beforeUpdate and afterUpdate methods, and I use an entity manager to update a single column on a single entity, the afterUpdate method on the subscriber should be called with an updatedColumns argument which is an array of ColumnMetadata that has a single entry, which describes the entity.

Actual Behavior

When I define an event subscriber with beforeUpdate and afterUpdate methods, and I use an entity manager to update a single field/column on a single entity, the afterUpdate method on the subscriber is called with an updatedColumns argument which has an array of ColumnMetadata that with two entries, both of which describe the same column

Steps to reproduce

I've written a reproducable example using a NestJS template app here.

$ git clone --depth 1 git@github.com:powerbill/nest-typeorm-subsubscriber-sadness.git
$ cd nest-typeorm-subsubscriber-sadness
$ yarn install
$ yarn test

My Environment

Additional Context

This happens even if the beforeUpdate and afterUpdate methods are defined on different objects which listenTo the same entity type.

I've tested this against postgres and sqlite

Relevant Database Driver(s)

• aurora-mysql
• aurora-postgres
• better-sqlite3
• cockroachdb
• cordova
• expo
• mongodb
• mysql
• nativescript
• oracle
• postgres
• react-native
• sap
• spanner
• sqlite
• sqlite-abstract
• sqljs
• sqlserver

Are you willing to resolve this issue by submitting a Pull Request?

Yes, I have the time, but I don't know how to start. I would need guidance.