[CONFIGURATION-840] StackOverflowError when adding property in

garydgregory · garydgregory · commit 56b5c4dcdffb · 2024-03-13T22:34:15.000-04:00
AbstractListDelimiterHandler.flattenIterator()
diff --git a/src/changes/changes.xml b/src/changes/changes.xml
@@ -24,6 +24,8 @@
   </properties>
   <body>
     <release version="2.10.1" date="YYYY-MM-DD" description="Minor release with new features and updated dependencies.">
+      <!-- FIX -->
+      <action type="fix" issue="CONFIGURATION-840" dev="ggregory" due-to="Gary Gregory">StackOverflowError when adding property in AbstractListDelimiterHandler.flattenIterator().</action>
       <!-- UPDATE -->
       <action type="update" dev="ggregory" due-to="Dependabot">Bump jackson-databind from 2.16.1 to 2.17.0 #297, #303, #326, #331, #340, #378.</action>
       <action type="update" dev="ggregory" due-to="Dependabot">Bump log4j.version from 2.23.0 to 2.23.1 #379.</action>
diff --git a/src/main/java/org/apache/commons/configuration2/convert/ListDelimiterHandler.java b/src/main/java/org/apache/commons/configuration2/convert/ListDelimiterHandler.java
@@ -17,6 +17,7 @@
 package org.apache.commons.configuration2.convert;
 
 import java.lang.reflect.Array;
+import java.nio.file.Path;
 import java.util.Collection;
 import java.util.Iterator;
 import java.util.LinkedList;
@@ -121,7 +122,10 @@ default Collection<?> flatten(final Object value, final int limit) {
             return split((String) value, true);
         }
         final Collection<Object> result = new LinkedList<>();
-        if (value instanceof Iterable) {
+        if (value instanceof Path) {
+            // Don't handle as an Iterable.
+            result.add(value);
+        } else if (value instanceof Iterable) {
             AbstractListDelimiterHandler.flattenIterator(this, result, ((Iterable<?>) value).iterator(), limit);
         } else if (value instanceof Iterator) {
             AbstractListDelimiterHandler.flattenIterator(this, result, (Iterator<?>) value, limit);
diff --git a/src/test/java/org/apache/commons/configuration2/TestPropertiesConfiguration.java b/src/test/java/org/apache/commons/configuration2/TestPropertiesConfiguration.java
@@ -51,7 +51,9 @@
 import java.net.URLConnection;
 import java.net.URLStreamHandler;
 import java.nio.charset.StandardCharsets;
+import java.nio.file.FileSystems;
 import java.nio.file.Files;
+import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.util.ArrayDeque;
 import java.util.ArrayList;
@@ -433,6 +435,20 @@ public void testComment() {
         assertFalse(conf.containsKey("!comment"));
     }
 
+    @Test
+    public void testCompress840() {
+        final PropertiesConfiguration configuration = new PropertiesConfiguration();
+        final Path path = FileSystems.getDefault().getPath("bar");
+        final ListDelimiterHandler listDelimiterHandler = configuration.getListDelimiterHandler();
+        listDelimiterHandler.flatten(path, 0);
+        // Stack overflow:
+        listDelimiterHandler.flatten(path, 1);
+        listDelimiterHandler.flatten(path, Integer.MAX_VALUE);
+        listDelimiterHandler.parse(path);
+        configuration.addProperty("foo", path);
+        configuration.toString();
+    }
+
     /**
      * Tests copying another configuration into the test configuration. This test ensures that the layout object is informed
      * about the newly added properties.
