703             # old cache key is now invalid for the repo, but we've just updated

   706             # the tiprev and tipnode should be aligned, so if the current repo

   704             # the cache and we assume it's valid, so let's make the cache key

   707             # is not seens as valid this is because old cache key is now

   705             # valid as well by recomputing it from the cached data

   708             # invalid for the repo.

   706             self.tipnode = repo.nullid

   709             #

   707             self.tiprev = nullrev

   710             # However. we've just updated the cache and we assume it's valid,

   708             for heads in self.iterheads():

   711             # so let's make the cache key valid as well by recomputing it from

   709                 if not heads:

   712             # the cached data

   710                     # all revisions on a branch are obsolete

   713             self.filteredhash = scmutil.filteredhash(

   711                     continue

   714                 repo, self.tiprev, needobsolete=True

   712                 # note: tiprev is not necessarily the tip revision of repo,

   715             )

   713                 # because the tip could be obsolete (i.e. not a head)

   716 

   714                 tiprev = max(cl.rev(node) for node in heads)

   715                 if tiprev > self.tiprev:

   716                     self.tipnode = cl.node(tiprev)

   717                     self.tiprev = tiprev

   718         self.filteredhash = scmutil.filteredhash(

   719             repo, self.tiprev, needobsolete=True

   720         )