question: @ NotNull public Couple < HgRevisionNumber > parents ( @ NotNull VirtualFile repo , @ Nullable FilePath file , @ Nullable HgRevisionNumber revision ) { final List < HgRevisionNumber > revisions = getRevisions ( repo , "parents" , file , revision , true ) ; switch ( revisions . size ( ) ) { case 1 : return Couple . of ( revisions . get ( 0 ) , null ) ; case 2 : return Couple . of ( revisions . get ( 0 ) , revisions . get ( 1 ) ) ; default : return Couple . of ( null , null ) ; } }
target:  Parent(s) of the given revision of the given file. If there are two of them (in the case of merge) the first element of the pair is the latest parent (i.e. having greater revision number), second one is the earlier parent (having smaller revision number).