try to use blob and commit for changed file

.githooks/post-merge

@@ -23,28 +23,34 @@ get_blob () {   # get the blob of the file(name) passed as $1
 }
 
 get_commit_for_blob () {
-    blob=$(get_blob $1)
+    if [ ! -z $1 ]; then
-    if [ ! -z $blob ]; then
         # search for the blob in all commits for the file(name) $1
         echo $(echo $(git log --all --pretty=format:%H -- $1) |
                xargs -I{} bash -c "git ls-tree {} -- $1       |
-               grep -q $blob && echo {}")
+               grep -q $1 && echo {}")
     fi
 }
 
 changed_file_names () {
     for fn in $(git diff-tree -r HEAD@{1} HEAD --name-only); do
+        # called in repository: $fn is e.g. etc/psa_tariff/tariff01.json
+        # add '/' prefix
+        fn=$(echo $fn | awk '{ printf "/"$0 }')
         CHANGED_FILE_NAMES+=($fn)
     done
 }
 
 for fn in $(git diff-tree -r HEAD@{1} HEAD --name-only); do
     if grep -E -q "(DC.*json|dc.*hex|dc.*bin|tariff.*json)" <<< $fn; then
-        fsize=0
+        # called in repository: $fn is e.g. etc/psa_tariff/tariff01.json
+        # add '/' prefix
+        fn=$(echo $fn | awk '{ printf "/"$0 }')
         if [[ -f "$fn" ]]; then
+            blob=$(get_blob "$fn")
+            commit=$(get_commit_for_blob $blob)
             fsize=$(ls -l "$fn" | awk '{ print $5 }')
+            echo "$fn $fsize $blob $commit" >> $GIT_PULL_TMP
         fi
-        echo "$fn $fsize" >> $GIT_PULL_TMP
     fi
     if grep -E -q ".*opkg_commands" <<< $fn; then
         readarray opkg_commands < <(cat $fn)