The entertaining but often deliberately inaccurate CinemaSins channel put out this video some time ago:
At 5:24, they have this dialogue:
RON: Don't remember this [the tunnel from the Hog's Head Inn to the Room of Requirement] on the Marauder's Map.
NEVILLE: That's because it never existed til now.
JEREMY (V.O.): So... a magical painting of Dumbledore's sister just dug a secret tunnel to Hogwarts. THAT I am totally down with and have no questions about. [Goes on to ask why they didn't do this in the previous seven movies.]
- Do the books clarify this?
- Did CinemaSins accidentally on purpose leave out the part where the movie clarifies this?
- Or did Neville actually mean the tunnel was brand new?
Charitably, I'd like to interpret Neville's "now" as "this year or thereabouts" rather than "literally right now". That would certainly be consistent with Ron never having seen the tunnel on the Marauder's Map. But I would be interested in hearing if Dumbledore's Army or anyone else had been using the tunnel before this point in the story. It does seem very convenient to the plot that they can just smuggle Harry and company into Hogwarts as soon as they arrive in Hogsmeade.