From patchwork Wed Oct 10 08:41:46 2018
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Subject: [2, of, 5,
 V5] context: take advantage of `_descendantrev` in introrev if
 available
From: Boris Feld <boris.feld@octobus.net>
X-Patchwork-Id: 35596
Message-Id: <927d87bd28e0e7791b49.1539160906@localhost.localdomain>
To: mercurial-devel@mercurial-scm.org
Date: Wed, 10 Oct 2018 10:41:46 +0200

# HG changeset patch
# User Boris Feld <boris.feld@octobus.net>
# Date 1539125434 -7200
#      Wed Oct 10 00:50:34 2018 +0200
# Node ID 927d87bd28e0e7791b494a70701cb81a3ffad73d
# Parent  37ee24df8c3b342bde56b950aa09ac0d123e0145
# EXP-Topic copy-perf
# Available At https://bitbucket.org/octobus/mercurial-devel/
#              hg pull https://bitbucket.org/octobus/mercurial-devel/ -r 927d87bd28e0
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
@@ -782,6 +782,11 @@ 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()