Return empty String sequence in kind for in metaschema-framework#132

aj-stein-gsa · Oct 8, 2024 · ab628ef · ab628ef
1 parent a83404f
commit ab628ef
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Showing 2 changed files with 10 additions and 1 deletion.
diff --git a/...src/main/java/gov/nist/secauto/metaschema/core/metapath/function/library/FnSubstring.java b/...src/main/java/gov/nist/secauto/metaschema/core/metapath/function/library/FnSubstring.java
@@ -113,8 +113,14 @@ private static ISequence<IStringItem> execute(
    */
   @NonNull
   public static IStringItem substring(@NonNull IStringItem sourceString, @NonNull IDecimalItem start, @NonNull IDecimalItem length) {
+    String sourceStringData = sourceString.toString();
+
+    if (sourceStringData.length() == 0) {
+      return IStringItem.valueOf("");
+    }
+
     int startIndex = start.asInteger().intValue() - 1;
     int endIndex = startIndex + length.asInteger().intValue();
-    return IStringItem.valueOf(sourceString.toString().substring(startIndex, endIndex));
+    return IStringItem.valueOf(sourceStringData.substring(startIndex, endIndex));
   }
 }
diff --git a/...test/java/gov/nist/secauto/metaschema/core/metapath/function/library/FnSubstringTest.java b/...test/java/gov/nist/secauto/metaschema/core/metapath/function/library/FnSubstringTest.java
@@ -24,6 +24,9 @@ class FnSubstringTest
     extends ExpressionTestBase {
   private static Stream<Arguments> provideValues() { // NOPMD - false positive
     return Stream.of(
+        Arguments.of(
+            string(""),
+            "substring((), 1, 3)"),  
         Arguments.of(
             ISequence.of(string("ada")),
             "substring('metadata', 4, 3)"));