I actually hope the sale of JF-17s to Iran happen at some point down the line. There are some valid concerns but there is more to actually gain in that equation imo.
Lots of comments here are a typical Pakistani view point with little to no thought behind them but just one or two liners about brotherhood, trust and greed (read begging Saudis for money here).
Fact of the matter is Iran is a historically close ally of Pakistan that has never threatened us, and at their best, have openly helped us in times or dire need. Maybe some of the posters here don't know that when the US sanctioned us after 1965, Iran actually purchased 90 F-86s Sabres from Germany that ended up forming the majority of our airforce. Had it not been for those, the results of 1971 would have been much different. Iranians, if they are your friends, will stick with you through thick and thin. I can not say the same for any of the Arab states that Pakistan seems to be bowing before. Didn't the Saudis just a few months back vote against Pakistan as well that led us being put on the grey list for supporting terrorism?!!
The basic point here is this, Pakistan needs to grow up and stop living and acting like a 3rd grader. It needs to further its interests with vigor and stand up on principals, and not shed those principals at the first sight of trouble or lure of easy money. There are many examples that abound right around us, yet we are somehow to blind to see or too ignorant to acknowledge. Some like
@Horus have already pointed this out, but I will mention it again. Take the examples of our enemy and supposed brother. India, despite all their shortcomings, have managed a policy that is India first and have made others accept it. Heck, US just gave them a waiver to not just keep buying oil from their supposed worst enemy Iran, they also let them buy S-400 from their other supposed worst threat, Russia. Why? Self-interest. They want the Indian market access and to have them spend money buying American goods.
Similarly, despite having close economic relationships with Iran, India has in fact much stronger trade and bi-lateral relations with EVERY single Arab country then Pakistan. You don't see the likes of UAE or RSA complaining about them buying Iranian oil do you? Yet, even the thought of us somehow irking them by having normal relationships with our neighboring countries gives us the shivers (or perhaps withdrawals like an addict). Heck, we were just getting bullied by a puny country like Qatar just last month or two ago.
We can even take our own example. How many times have our relations soured with the US, UK and France, and yet we are always looking for ways to mend them. All those countries have sanctioned us multiple times in the past yet we have no problem getting those back on track.
I have said this before, and I still stand by it. Pakistan needs to ensure, by every measure possible, that the Pak-Iran border stays dormant for time immemorial, given the grave threat we are going to be facing from India in the coming decade (read water wars).
On the news itself, Pakistan has offered all middle eastern countries JF-17, be it to replace the F-7s or F-5s or old Mirages, and the aircraft is fully capable of performing very well in every single of those circumstances. Yet we have not scored a single order, and if we are honest, none of the Arab countries will ever buy if either. Most all of the potential buyers there have already committed to buying F-16s or Rafales. Iran, is it were to purchase JF-17 has the potential of becoming our largest buyer! And yes, they do have buying power (just look at the order books with Boeing when they thought Americans were sincere in removing sanctions). If they buy the Thunder, it will not only lower the cost of our own purchase, the infusion of the money will directly go into supporting future upgrades and even project Azm. If they want to build it in Iran, more power to them. We should gladly help set up manufacturing facilities in Iran and charge them for it, just like Egypt did when they produced their own K-8s and even Myanmar might be getting the capacity to locally overhaul their JF-17s. That doesn't mean they will be able to sell those to 3rd parties and no country in their right mind "shares" information about their tactical or strategic weapon systems with others (as some people here seem to imply viz-a-viz India). Heck, I would say, the Iranians would actually safeguard them from Indian eyes even more so then any other country we sell to, since the bhindians will gladly run to Americans and Israelis with whatever they learn the next day.
Anyways, this topic discussion can go on for a long time with me just scratching the surface here, but I will stay hopeful that Pakistan ensures a strong Iran, even if its just in order to save its own hide in the future. Yes I think its only a matter of time that once the powers to be are done destroying another Muslim country, they will turn their efforts on Pakistan. For that to not happen, we need to have a multi-pronged strategy or not just uplifting our country from poverty, nepotism and corruption, but also make sure our neighborhood does not see the kind of destruction and generation-uprooting events that are happening in the ME for the last decade.