We were on the April 28 - May 8 sailing on the Holland American Noordam, and we were at sea in the middle of all of the confusion. It's a political situation. Basically, Gibraltar is a UK territory, and Spain wants it back. The new Spanish government has reenacted enforcement of a law stating that if you call at Gibraltar, the ship must sail back out into international waters prior to calling at a port in Spain. NCL did not get its act together during this time and was turned away from the port when they called in Barcelona. The passengers on that sailing also missed another port and were not happy. NCL should have known of the new laws and has mismanaged yet another situation and caused more passengers to not get what they paid for. It is my understanding that the other ships in that area during late April and early June were able to make small adjustments and did not miss any ports.
Our ship was scheduled to call at Ceuta in Spanish Morrocco and could not get into that port due to weather (sunny and warm but windy). Our captain then planned to take us to Gibraltar but was advised by Holland that if we called at Gibraltar, we would then have to sail back out into international waters or we would be turned away from our ports in Barcelona and in Mahon, Minorca (an island off the coast of Spain). Since Holland has its act together, we didn't miss any ports of call other than our 6-hour stop in Morrocco, which we missed due to weather. We were also advised of NCL's failure to obey the laws and the subsequent cancellation of two ports of call.
This is one of the many reasons why we don't cruise NCL any more.
So since this is no longer a new situation, your cruise line probably has it under control, but it wouldn't hurt to have your travel agent check. My husband was very excited about the possibility of exploring the caves in Gibraltar, and I understand it's a nice port, so I hope it works out for you.
Have a great trip,