From patchwork Wed Jan 15 14:58:27 2020
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Subject: D7892: nodemap: never read more than the expected data amount
From: phabricator <phabricator@mercurial-scm.org>
X-Patchwork-Id: 44381
Message-Id: <differential-rev-PHID-DREV-npxosq2vokbxnyki2z36-req@mercurial-scm.org>
To: Phabricator <phabricator@mercurial-scm.org>
Cc: mercurial-devel@mercurial-scm.org
Date: Wed, 15 Jan 2020 14:58:27 +0000

marmoute created this revision.
Herald added a subscriber: mercurial-devel.
Herald added a reviewer: hg-reviewers.

REVISION SUMMARY
  Since we are tracking this number we can use it to detect corrupted rawdata file
  and to only read the correct amount of data when possible.

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D7892

AFFECTED FILES
  mercurial/revlogutils/nodemap.py

CHANGE DETAILS




To: marmoute, #hg-reviewers
Cc: mercurial-devel

diff --git a/mercurial/revlogutils/nodemap.py b/mercurial/revlogutils/nodemap.py
--- a/mercurial/revlogutils/nodemap.py
+++ b/mercurial/revlogutils/nodemap.py
@@ -45,7 +45,12 @@
     docket.data_unused = data_unused
 
     filename = _rawdata_filepath(revlog, docket)
-    return docket, revlog.opener.tryread(filename)
+    data = revlog.opener.tryread(filename)
+    if len(data) < data_length:
+        return None
+    elif len(data) > data_length:
+        data = data[:data_length]
+    return docket, data
 
 
 def setup_persistent_nodemap(tr, revlog):