fix: not deep clone custom dialectModule option

[JerrysShan]

Description Of Change

deep clone custom dialectModule option cause unexpected behavior.
If dialectModule is a complex object, I hope it is a reference rather than a deep clone.

[JerrysShan]

@WikiRik May I ask when this pull request can be merged?

[WikiRik]

Can you share a bit more on why this is better. Do you have an example of where it causes unexpected behaviour as you mentioned?

This behaviour also seems to be present in the v7 alphas, where we converted the ConnectionManager to TypeScript. That should also be updated in the case that this is considered a beneficial change.

[JerrysShan]

Can you share a bit more on why this is better. Do you have an example of where it causes unexpected behaviour as you mentioned?

This behaviour also seems to be present in the v7 alphas, where we converted the ConnectionManager to TypeScript. That should also be updated in the case that this is considered a beneficial change.

In the case I encountered, the dialectModule object was customized, and the object has a property _ctx , but the descriptor enumable of this property was false; this property was ignored during deep clone, resulting in unexpected behavior.

[JerrysShan]

The other options of sequelize conifg are simple objects or values, and deep clone is expected to have no side effects; but the dialectModule option is special and needs to be an object containing the createConnection function.