Add a script to coalesce the valgrind outputs

After running the valgrind tests with GIT_TEST_TREE=t, the test output
is in the test-results/$TEST.out files.

Call ./valgrind/analyze.sh in $GIT_ROOT/t/ to group the valgrind errors
by backtrace.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/t/valgrind/analyze.sh b/t/valgrind/analyze.sh
new file mode 100755 (executable)
index 0000000..d8105d9
--- /dev/null
+++ b/t/valgrind/analyze.sh
@@ -0,0 +1,123 @@
+#!/bin/sh
+
+out_prefix=$(dirname "$0")/../test-results/valgrind.out
+output=
+count=0
+total_count=0
+missing_message=
+new_line='
+'
+
+# start outputting the current valgrind error in $out_prefix.++$count,
+# and the test case which failed in the corresponding .message file
+start_output () {
+       test -z "$output" || return
+
+       # progress
+       total_count=$(($total_count+1))
+       test -t 2 && printf "\rFound %d errors" $total_count >&2
+
+       count=$(($count+1))
+       output=$out_prefix.$count
+       : > $output
+
+       echo "*** $1 ***" > $output.message
+}
+
+finish_output () {
+       test ! -z "$output" || return
+       output=
+
+       # if a test case has more than one valgrind error, we need to
+       # copy the last .message file to the previous errors
+       test -z "$missing_message" || {
+               while test $missing_message -lt $count
+               do
+                       cp $out_prefix.$count.message \
+                               $out_prefix.$missing_message.message
+                       missing_message=$(($missing_message+1))
+               done
+               missing_message=
+       }
+}
+
+# group the valgrind errors by backtrace
+output_all () {
+       last_line=
+       j=0
+       i=1
+       while test $i -le $count
+       do
+               # output <number> <backtrace-in-one-line>
+               echo "$i $(tr '\n' ' ' < $out_prefix.$i)"
+               i=$(($i+1))
+       done |
+       sort -t ' ' -k 2 | # order by <backtrace-in-one-line>
+       while read number line
+       do
+               # find duplicates, do not output backtrace twice
+               if test "$line" != "$last_line"
+               then
+                       last_line=$line
+                       j=$(($j+1))
+                       printf "\nValgrind error $j:\n\n"
+                       cat $out_prefix.$number
+                       printf "\nfound in:\n"
+               fi
+               # print the test case where this came from
+               printf "\n"
+               cat $out_prefix.$number.message
+       done
+}
+
+handle_one () {
+       OLDIFS=$IFS
+       IFS="$new_line"
+       while read line
+       do
+               case "$line" in
+               # backtrace, possibly a new one
+               ==[0-9]*)
+
+                       # Does the current valgrind error have a message yet?
+                       case "$output" in
+                       *.message)
+                               test -z "$missing_message" &&
+                               missing_message=$count
+                               output=
+                       esac
+
+                       start_output $(basename $1)
+                       echo "$line" |
+                       sed 's/==[0-9]*==/==valgrind==/' >> $output
+                       ;;
+               # end of backtrace
+               '}')
+                       test -z "$output" || {
+                               echo "$line" >> $output
+                               test $output = ${output%.message} &&
+                               output=$output.message
+                       }
+                       ;;
+               # end of test case
+               '')
+                       finish_output
+                       ;;
+               # normal line; if $output is set, print the line
+               *)
+                       test -z "$output" || echo "$line" >> $output
+                       ;;
+               esac
+       done < $1
+       IFS=$OLDIFS
+
+       # just to be safe
+       finish_output
+}
+
+for test_script in "$(dirname "$0")"/../test-results/*.out
+do
+       handle_one $test_script
+done
+
+output_all