I am referring to the G-F# in m. 123. We are in G major, as I understand, heading to a PAC (m. 126) that will be reinterpreted as a half-cadence when the subordinate theme starts at m. 127.
I am currently understanding that the F#, perhaps in a incomplete D7 harmony, is a leading tone to G, in a incomplete G harmony given by the double-neighbor around B at m. 124 and the following D. For that interpretation, one has to consider that the G in the bass is a tonic pedal. I'm not used to seeing pedal points that brief, even less so with such sharp dissonances (the G-F# really pops out to my ear), hence the discomfort with the current analysis. Is this a common in the classical style? Am I missing something here?