bin/get-fixes-pick-list.sh: add new script

The script parses the "Fixes" tags and nominates respective commit if
applicable.

Cc: "13.0 17.0" <mesa-stable@lists.freedesktop.org>
Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>

bin/get-fixes-pick-list.sh

@@ -0,0 +1,61 @@
+#!/bin/bash
+
+# Script for generating a list of candidates [referenced by a Fixes tag] for
+# cherry-picking to a stable branch
+#
+# Usage examples:
+#
+# $ bin/get-fixes-pick-list.sh
+# $ bin/get-fixes-pick-list.sh > picklist
+# $ bin/get-fixes-pick-list.sh | tee picklist
+
+# Use the last branchpoint as our limit for the search
+latest_branchpoint=`git merge-base origin/master HEAD`
+
+# List all the commits between day 1 and the branch point...
+git log --reverse --pretty=%H $latest_branchpoint > already_landed
+
+# ... and the ones cherry-picked.
+git log --reverse --grep="cherry picked from commit" $latest_branchpoint..HEAD |\
+	grep "cherry picked from commit" |\
+	sed -e 's/^[[:space:]]*(cherry picked from commit[[:space:]]*//' -e 's/)//'  > already_picked
+
+# Grep for commits with Fixes tag
+git log --reverse --pretty=%H -i --grep="fixes:" $latest_branchpoint..origin/master |\
+while read sha
+do
+	# For each one try to extract the tag
+	fixes_count=`git show $sha | grep -i "fixes:" | wc -l`
+	if [ "x$fixes_count" != x1 ] ; then
+		echo WARNING: Commit $sha has nore than one Fixes tag
+	fi
+	fixes=`git show $sha | grep -i "fixes:" | head -n 1`
+	# The following sed/cut combination is borrowed from GregKH
+	id=`echo ${fixes} | sed -e 's/^[ \t]*//' | cut -f 2 -d ':' | sed -e 's/^[ \t]*//' | cut -f 1 -d ' '`
+
+	# Bail out if we cannot find suitable id.
+	# Any specific validation the $id is valid and not some junk, is
+	# implied with the follow up code
+	if [ "x$id" = x ] ; then
+		continue
+	fi
+
+	# Check if the offending commit is in branch.
+
+	# Be that cherry-picked ...
+	# ... or landed before the branchpoint.
+	if grep -q ^$id already_picked ||
+	   grep -q ^$id already_landed ; then
+
+		# Finally nominate the fix if it hasn't landed yet.
+		if grep -q ^$sha already_picked ; then
+			continue
+		fi
+
+		echo Commit $sha fixes $id
+	fi
+
+done
+
+rm -f already_picked
+rm -f already_landed