Merge "Fix lintstack check for multi-patch reviews"

1 files changed, 22 insertions, 4 deletions

diff --git a/tools/lintstack.sh b/tools/lintstack.sh
index 848a16fa5..42c6a60b3 100755
--- a/tools/lintstack.sh
+++ b/tools/lintstack.sh
@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 
-# Copyright (c) 2012, AT&T Labs, Yun Mao <yunmao@gmail.com>
+# Copyright (c) 2012-2013, AT&T Labs, Yun Mao <yunmao@gmail.com>
 # All Rights Reserved.
 #
 #    Licensed under the Apache License, Version 2.0 (the "License"); you may
@@ -15,13 +15,31 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-# Use lintstack.py to compare pylint errors between HEAD and HEAD~1
-
+# Use lintstack.py to compare pylint errors.
+# We run pylint twice, once on HEAD, once on the code before the latest
+# commit for review.
 set -e
 TOOLS_DIR=$(cd $(dirname "$0") && pwd)
 GITHEAD=`git rev-parse HEAD`
 cp -f $TOOLS_DIR/lintstack.py $TOOLS_DIR/lintstack.head.py
-git checkout HEAD~1
+
+if git rev-parse HEAD^2 2>/dev/null; then
+    # The HEAD is a Merge commit. Here, the patch to review is
+    # HEAD^2, the master branch is at HEAD^1, and the patch was
+    # written based on HEAD^2~1.
+    PREV_COMMIT=`git rev-parse HEAD^2~1`
+    git checkout HEAD~1
+    # The git merge is necessary for reviews with a series of patches.
+    # If not, this is a no-op so won't hurt either.
+    git merge $PREV_COMMIT
+else
+    # The HEAD is not a merge commit. This won't happen on gerrit.
+    # Most likely you are running against your own patch locally.
+    # We assume the patch to examine is HEAD, and we compare it against
+    # HEAD~1
+    git checkout HEAD~1
+fi
+
 # First generate tools/pylint_exceptions from HEAD~1
 $TOOLS_DIR/lintstack.head.py generate
 # Then use that as a reference to compare against HEAD