Method SetNetConnAndInitConn

internal/pool/conn.go:675–712

SetNetConnAndInitConn replaces the underlying connection and executes the initialization. This method ensures only one initialization can happen at a time by using atomic state transitions. If another goroutine is currently initializing, this will wait for it to complete.

(ctx context.Context, netConn net.Conn)

// This method ensures only one initialization can happen at a time by using atomic state transitions.
// If another goroutine is currently initializing, this will wait for it to complete.
func (cn *Conn) SetNetConnAndInitConn(ctx context.Context, netConn net.Conn) error {
	// Wait for and transition to INITIALIZING state - this prevents concurrent initializations
	// Valid from states: CREATED (first init), IDLE (reconnect), UNUSABLE (handoff/reauth)
	// If another goroutine is initializing, we'll wait for it to finish
	// if the context has a deadline, use that, otherwise use the connection read (relaxed) timeout
	// which should be set during handoff. If it is not set, use a 5 second default
	deadline, ok := ctx.Deadline()
	if !ok {
		deadline = time.Now().Add(cn.getEffectiveReadTimeout(5 * time.Second))
	}
	waitCtx, cancel := context.WithDeadline(ctx, deadline)
	defer cancel()
	// Use predefined slice to avoid allocation
	finalState, err := cn.stateMachine.AwaitAndTransition(
		waitCtx,
		validFromCreatedIdleOrUnusable,
		StateInitializing,
	)
	if err != nil {
		return fmt.Errorf("cannot initialize connection from state %s: %w", finalState, err)
	}

	// Replace the underlying connection
	cn.SetNetConn(netConn)

	// Execute initialization
	// NOTE: ExecuteInitConn (via baseClient.initConn) will transition to IDLE on success
	// or CLOSED on failure. We don't need to do it here.
	// NOTE: Initconn returns conn in IDLE state
	initErr := cn.ExecuteInitConn(ctx)
	if initErr != nil {
		// ExecuteInitConn already transitioned to CLOSED, just return the error
		return initErr
	}

	// ExecuteInitConn already transitioned to IDLE
	return nil
}

// MarkForHandoff marks the connection for handoff due to MOVING notification.
// Returns an error if the connection is already marked for handoff.