When trying to update update: false column with @UpdateDateColumn the update column is updated

[rluvaton]

Issue Description

Let's say I have this entity:

@Entity()
export class Post {

    @PrimaryGeneratedColumn()
    id: number;

    // Extra, not required column just for the example
    @Column()
    title: string;

    @UpdateDateColumn()
    lastUpdated: Date;

    @Column({
        // Forcing this column to only be written on insert time
        update: false
    })
    readOnlyColumn: number;
}

And I try to update the readOnlyColumn column

Expected Behavior

Should not update the readOnlyColumn AND should not update the lastUpdated column

Actual Behavior

Update the lastUpdated column

Steps to Reproduce

Reproduction Repo, It contains docker-compose.yml and the minimal code that is required to create this issue.

Just run npm i && npm start and it will start the DB and the "test"

My Environment

Plain TS

Dependency	Version
Operating System	Windows 11
Node.js version	v16.6.2
Typescript version	v4.5.2
TypeORM version	v0.2.41

Additional Context

Relevant Database Driver(s)

I think this bug affects all DBs

DB Type	Reproducible
aurora-data-api	no
aurora-data-api-pg	no
better-sqlite3	no
cockroachdb	no
cordova	no
expo	no
mongodb	no
mysql	no
nativescript	no
oracle	no
postgres	yes
react-native	no
sap	no
sqlite	no
sqlite-abstract	no
sqljs	no
sqlserver	no

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.

[rluvaton]

Added a failing tests represent this issue in the linked PR...

[spotykatch]

Did that happen in earlier releases?

[rluvaton]

Did that happen in earlier releases?

Yeah, just tested it in v0.2.20 (little after readonly option change to update) and it didn't work back then either...

[rluvaton]

I found the issue in the code...

typeorm/src/query-builder/UpdateQueryBuilder.ts

Lines 446 to 447 in dd94c9d

	if (metadata.updateDateColumn && updatedColumns.indexOf(metadata.updateDateColumn) === -1)
	updateColumnAndValues.push(this.escape(metadata.updateDateColumn.databaseName) + " = CURRENT_TIMESTAMP"); // todo: fix issue with CURRENT_TIMESTAMP(6) being used, can "DEFAULT" be used?!

Few questions on how should we handle it:

1. What should we do in case of trying to update update: false column? throw? (currently, it's not doing anything)

2. Should we allow calling manager.update without columns when the update date/version column exists?

   e.g. Should we allow:

   await connection.manager.update(T, t.id, {});

   Currently, if they are not a UpdateValuesMissingError gonna be thrown...