When successfully trading with a villager that has the "NoAI" tag set to 1, their "uses" tag is updated based on how much you've traded with them. It should be expected that this value does not change (as their "maxUses" tag does not).
/summon Villager ~ ~ ~ {NoAI:1}/summon Villager ~ ~ ~ {NoAI:1}Comments 7
With 1.8's villager trading update, the "maxUses" tag will increase by a random amount when trading (2 to 12 according to the wiki, which appears correct from testing). With "NoAI" set to 1, "maxUses" doesn't change, probably considering that "successful trades" can't really occur (though "uses" still increments after trading).
Well what I mean is the villager won't refresh its trades because of the "NoAI" tag. Once you finish successfully trading with a villager and exit the interface, they would normally go through the process of generating new trades and refreshing old ones (which is when "maxUses" would increase I believe). "NoAI" set to 1 prevents this process, but "uses" still increases after trading.
Though it doesn't look as if the "uses" tag is a part of the refreshing process, so I'm unsure if it's intended. If so, a guaranteed 4 billion trades is certainly well enough, as there wasn't a way to disable "maxUses" beforehand! Just have no idea how far "NoAI" is supposed to go with its duties.
Is this still a concern in the current Minecraft version? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases. If this has been done, we can reopen the issue.
Keep in mind that the "Resolved"-Status on this ticket just means "Answered", and that we are waiting for further information on whether this issue still exists or not. We will reopen it as soon as the requested information has been delivered.
Can you explain what maxUses does? My interpretation is that maxUses would be a constant, and uses the current.