Fixes the list inside a File.ext YAML key pattern is not correctly parsed

lib/parser.js

@@ -143,15 +143,22 @@
       if (valuePathSplit.length > 1) {
         // The value is inside an array
         const arrayPrefix = utils.getArrayPrefix(valuePath);
-        let isPlainArray = true; // Assume it is plain until we prove the opposite
-        _.get(valuesJSON, arrayPrefix).forEach((e) => {
-          if (typeof e !== 'string') {
-            isPlainArray = false;
+        // Retrieve the value at arrayPrefix only if it's defined
+        const array = _.get(valuesJSON, arrayPrefix);
+        // Ensure array is actually defined and is an array
+        if (Array.isArray(array)) {
+          let isPlainArray = true; // Assume it is plain until we prove the opposite
+          array.forEach((e) => {
+            if (typeof e !== 'string') {
+              isPlainArray = false;
+            }
+          });
+          if (isPlainArray) {
+            value = array;
+            valuePath = arrayPrefix;
           }
-        });
-        if (isPlainArray) {
-          value = _.get(valuesJSON, arrayPrefix);
-          valuePath = arrayPrefix;
+        } else {
+          console.error(`Expected array at ${arrayPrefix}, found ${typeof array}`);
         }
       }