Request: Public API for connection validation

[mercmobily]

Knex.js needs to validate mysql2 connections before use in connection pools. Currently, we're forced to use private properties that could break with any update.

Current Situation

// Knex's mysql2 dialect - relies on private properties
validateConnection(connection) {
  return (
    connection &&
    !connection._fatalError &&      // Private
    !connection._protocolError &&   // Private
    !connection._closing &&         // Private
    !connection.stream.destroyed
  );
}

For comparison, the original mysql driver provides public API:

// mysql driver - uses public 'state' property
validateConnection(connection) {
  return connection.state === 'connected' || connection.state === 'authenticated';
}

Background

In 2017, you kindly offered to add public API for this (knex#2175):

I'm happy to add anything that would work for you, ideally in a way compatible with mysqljs/mysql
what if I wrap _fatalError into a getter function and "bless" it to be public api?

This would still be incredibly helpful for connection pool management.

Request

Could mysql2 provide one of these public methods?

Option A: Simple boolean check

connection.isValid()  // returns true/false

Option B: State property (mysql compatible)

connection.state  // 'connected' | 'disconnected' | 'protocol_error' | 'closing'

Option C: Expose existing checks

connection.hasFatalError()     // or
connection.hasProtocolError()  // or
connection.isClosing()

Related Issues

• MySQL2 dialect relies on private API for connection validation knex/knex#6255 - MySQL2 relies on private API for connection validation
• Unhandled Exception in connection.end() for MySQL Dialect knex/knex#1798 - Original connection handling issue
• Recognize fatal mysql2 connection errors knex/knex#2175 - Previous attempt to improve validation

Would you consider adding any of these public methods? Option B would maintain compatibility with the original mysql driver, making migration easier for users.

Thank you for maintaining this excellent library!