changeset 3266:bc173e7f3b6f

stablesort: simplify processing of non-merge changesets

As long as a changeset as only one parent, the next element in the sort (starting
from the head) has to be that parent. We detect and take advantage of that
shortcut in the non-merge case.

--- a/hgext3rd/evolve/stablesort.py	Sat Nov 25 18:42:23 2017 -0500
+++ b/hgext3rd/evolve/stablesort.py	Sat Nov 25 18:53:23 2017 -0500
@@ -314,8 +314,23 @@
         return result
 
     def _revsfrom(self, repo, head):
-        for rev in stablesort_mergepoint_head(repo, head)[::-1]:
-            yield rev
+        parentsfunc = repo.changelog.parentrevs
+
+        def parents(rev):
+            return [p for p in parentsfunc(current) if p is not nodemod.nullrev]
+
+        current = head
+        ps = parents(current)
+        while len(ps) == 1:
+            yield current
+            current = ps[0]
+            ps = parents(current)
+
+        if not ps:
+            yield current
+        elif len(ps) == 2:
+            for rev in stablesort_mergepoint_head(repo, current)[::-1]:
+                yield rev
 
 _methodmap = {
     'branchpoint': stablesort_branchpoint,