From patchwork Tue Mar 28 07:49:08 2017
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Subject: [7, of,
 7] revlog: avoid apply delta chain when cache hit in revlog.revision
From: Jun Wu <quark@fb.com>
X-Patchwork-Id: 19777
Message-Id: <8c9f728ef3a3fff029d7.1490687348@localhost.localdomain>
To: <mercurial-devel@mercurial-scm.org>
Date: Tue, 28 Mar 2017 00:49:08 -0700

# HG changeset patch
# User Jun Wu <quark@fb.com>
# Date 1490683696 25200
#      Mon Mar 27 23:48:16 2017 -0700
# Node ID 8c9f728ef3a3fff029d7fe6c875ed783c66dc254
# Parent  d3d803ed16fe8e9d43f7a4daeca079e4022c297a
# Available At https://bitbucket.org/quark-zju/hg-draft
#              hg pull https://bitbucket.org/quark-zju/hg-draft -r 8c9f728ef3a3
revlog: avoid apply delta chain when cache hit in revlog.revision

Previously, revlog.revision(raw=False) may try to apply the delta chain
even on cache hit. That could happen if flags are non-empty so all fast
paths won't be executed. But if cache hit, the raw test is still useful.
So let's use it.

diff --git a/mercurial/revlog.py b/mercurial/revlog.py
--- a/mercurial/revlog.py
+++ b/mercurial/revlog.py
@@ -1259,19 +1259,20 @@ class revlog(object):
         cachedrev = None
         flags = None
+        text = None
         if node == nullid:
             return ""
         if self._cache:
             if self._cache[0] == node:
+                text = self._cache[2]
                 if raw:
-                    return self._cache[2]
+                    return text
                 if rev is None:
                     rev = self.rev(node)
                 flags = self.flags(rev)
                 if not flags:
-                    return self._cache[2]
+                    return text
             cachedrev = self._cache[1]
 
         # look up what we need to read
-        text = None
         if rev is None:
             rev = self.rev(node)