How often we sync p4's pna.p4 with pna repo ?

[kamleshbhalui]

I can see that there many new addition to pna.p4 in https://github.com/p4lang/pna.
Is there any guideline how often do we update this?

[ChrisDodd]

They should be kept in sync as often as necessary and possible,

[jafingerhut]

@kamleshbhalui Often sync'ing is not as straightforward as just copying the latest file and checking it in. It often requires updates to the PNA implementation using it, and not all of the PNA implementations in the p4c repo are equal in feature support, nor are they necessarily updated at the same time.

[qobilidop]

I've been thinking about this and proposed #4752 as a potential way to make it clearer which specific version of PNA each P4C backend is actually supporting, and what backend-specific customizations they have done.