Enhance Jenkins integration of safe templates take 2

- Handle case when no files are linted
- Skip deleted files for safe commit script
- Add verbose options for safe commit

scripts/safe-commit-linter.sh

@@ -19,6 +19,7 @@ show_help() {
     echo "  -m, --main-branch=COMMIT    Run against files changed between the"
     echo "                              current branch and this commit."
     echo "                              Defaults to origin/master."
+    echo "  -v, --verbose               Output details of git commands run."
     echo ""
     echo "This scripts does not give a grand total.  Be sure to check for"
     echo "0 violations on each file."
@@ -30,12 +31,25 @@ show_help() {
 
 }
 
+show_verbose() {
+    echo "Files linted is based on the following:"
+    echo "- Current commit: ${current_branch_hash}"
+    echo "- Main commit: ${MAIN_COMMIT}"
+    echo "- Merge base command: ${merge_base_command}"
+    echo "- Merge base: ${merge_base}"
+    echo "- Diff command: ${diff_command}"
+
+}
+
 for i in "$@"; do
     case $i in
         -m=*|--main-branch=*)
             MAIN_COMMIT="${i#*=}"
             shift # past argument=value
             ;;
+        -v|--verbose)
+            VERBOSE=true
+            ;;
         -h|--help|*)
             # help or unknown option
             show_help
@@ -51,11 +65,24 @@ if [ -z "${MAIN_COMMIT+x}" ]; then
     MAIN_COMMIT="origin/master"
 fi
 
-merge_base=`git merge-base "$current_branch_hash" "$MAIN_COMMIT"`
-diff_files=`git diff --name-only "$current_branch_hash" "$merge_base"`
+merge_base_command="git merge-base $current_branch_hash $MAIN_COMMIT"
+merge_base=$(${merge_base_command})
+diff_command="git diff --name-only --diff-filter=ACM $current_branch_hash $merge_base"
+diff_files=$(${diff_command})
 
-for f in $diff_files; do
+if [ "$diff_files" = "" ]; then
+    # When no files are found, automatically display verbose details to help
+    # understand why.
+    show_verbose
     echo ""
-    echo "Linting $f:"
-    ./scripts/safe_template_linter.py $f
-done
+    echo "No files linted."
+else
+    if [ ${VERBOSE} ] ; then
+        show_verbose
+    fi
+    for f in $diff_files; do
+        echo ""
+        echo "Linting $f:"
+        ./scripts/safe_template_linter.py $f
+    done
+fi