check valid files

eng/pipelines/vmr-sync-internal.yml

@@ -17,7 +17,7 @@ parameters:
 - name: vmrBranch
   displayName: dotnet-dotnet branch to push to
   type: string
-  default: ' '
+  default: ''
 
 variables: 
 - ${{ if ne(parameters.vmrBranch, ' ') }}:

eng/vmr-sync.sh

@@ -141,6 +141,16 @@ if [[ ! -d "$installer_dir" ]]; then
   exit 1
 fi
 
+if [[ ! -f "$readme_template" ]]; then
+  fail "File '$readme_template' does not exist. Please specify the path to the README template"
+  exit 1
+fi
+
+if [[ ! -f "$tpn_template" ]]; then
+  fail "File '$tpn_template' does not exist. Please specify the path to the THIRD-PARTY-NOTICES template"
+  exit 1
+fi
+
 if [[ -z "$tmp_dir" ]]; then
   fail "Missing --tmp-dir argument. Please specify the path to the temporary folder where the repositories will be cloned"
   exit 1