revlog: fix revset in reachableroots docstring `reachableroots` will only return a subset of `roots` when `includepath` is False. For example, given the following linear DAG: 2 | 1 | 0 Using roots=0+2, heads=1, the definition in the docstring does not match what `reachableroots` actually does: ipdb> repo.changelog.reachableroots(0, roots=[0,2],heads=[1]) [0] ipdb> repo.revs('heads(::(0+2) & (0+2)::1)') <baseset+ [1]> The fix is to do `heads & ::roots` (or `heads & heads::roots`) first, then select their ancestors: ipdb> repo.revs('heads(::((0+2) & (0+2)::1))') <baseset+ [0]> The docstring was introduced by fd92bfbbe02d9 (2015-06-19 "revset: rename revsbetween to reachableroots and add an argument"), which introduced the `includepath=False` behavior for graphlog grandparents use-case. I believe the docstring instead of the code should be changed because changing the code to match the docstring can result in suboptimal graphlog like: o :\ : o : : :/ o As opposite to the current "linearized" graphlog: o | o : o Differential Revision: https://phab.mercurial-scm.org/D7518

--- a/mercurial/revlog.py	Tue Nov 19 18:38:17 2019 -0800
+++ b/mercurial/revlog.py	Mon Nov 25 11:53:50 2019 -0800
@@ -1279,7 +1279,7 @@
         return bool(self.reachableroots(a, [b], [a], includepath=False))
 
     def reachableroots(self, minroot, heads, roots, includepath=False):
-        """return (heads(::<roots> and <roots>::<heads>))
+        """return (heads(::(<roots> and <roots>::<heads>)))
 
         If includepath is True, return (<roots>::<heads>)."""
         try: