# HG changeset patch
# User Boris Feld <boris.feld@octobus.net>
# Date 2018-10-09 22:50:34
# Node ID aee94f0a36cd7ddf1ea1435e410bb4e4fa8b5ff9
# Parent  f3f4d8537b11d5ba7c1b6323c784478741e46008

context: take advantage of `_descendantrev` in introrev if available

Before this changeset, `_descendantrev` was ignored and `introrev` could
return a "wrong" result. I was previously fine because there seems to be no
existing code using both `introrev` and `_descendantrev` at the same time.
However, we would like to change that.

diff --git a/mercurial/context.py b/mercurial/context.py
--- a/mercurial/context.py
+++ b/mercurial/context.py
@@ -780,6 +780,11 @@ class basefilectx(object):
 
         if toprev is not None:
             return self._adjustlinkrev(toprev, inclusive=True)
+        elif r'_descendantrev' in attrs:
+            introrev = self._adjustlinkrev(self._descendantrev)
+            # be nice and cache the result of the computation
+            self._changeid = introrev
+            return introrev
         else:
             return self.linkrev()