As salamu alaykum,
I read in a book that according to Abu Hanifa if the time for the current salah ends or a other salah time enters after sitting in the last tashahhud for the duration of the tahiyyaat, the salah brakes, whereas according to his two students Imam Muhammad and Abu Yusuf the prayer is valid.
The upshot for this rulings would be that according to Abu Hanifa leaving the salah with ones own will (khuruj bi sunihi) is Fard, whereas according to his students the salah is complete when one sits for the duration of tahiyyaat.
Is this correct, and does this ruling count for every salah ?
Does this also mean, that someone must be shure that he will complete the whole salah before the time for the current salah ends, otherwise his salah will break and he must make qadha of it afterwards ?