JSPWIKI-388 updates existing PR and fixes merge conflicts

jspwiki-main/src/main/java/org/apache/wiki/tags/ParamTag.java

@@ -21,6 +21,8 @@ Licensed to the Apache Software Foundation (ASF) under one
 import jakarta.servlet.jsp.tagext.BodyContent;
 import jakarta.servlet.jsp.tagext.BodyTagSupport;
 import jakarta.servlet.jsp.tagext.Tag;
+import java.util.HashSet;
+import java.util.Set;
 
 /**
  * ParamTag submits name-value pairs to the first enclosing 
@@ -74,30 +76,36 @@ public void setValue(final String s )
     @Override
     public int doEndTag()
     {
-        Tag t;
-        do
-        {
-            t = getParent();
-        } while (t != null && !(t instanceof ParamHandler));
+        // Start with the direct parent of this tag
+        Tag t = getParent();
+        final Set<Tag> visited = new HashSet<>();
+
+        // Keep moving up the tree until we find a parent that is a ParamHandler,
+        // or until we run out of parents. This prevents an infinite loop in case
+        // the parent of this tag is not a ParamHandler.
+        while (t != null && !(t instanceof ParamHandler)) {
+            if (!visited.add(t)) {
+                break; // We've seen this tag before, so break out of the loop
+            }
+            t = t.getParent();
+        }
 
         if( t != null )
         {
             String val = m_value;
             if( val == null )
             {
                 final BodyContent bc = getBodyContent();
-                if( bc != null ) 
+                if( bc != null )
                 {
                     val = bc.getString();
                 }
             }
-            if( val != null ) 
+            if( val != null )
             {
                 ((ParamHandler)t).setContainedParameter( m_name, val );
             }
         }
-
-
         return EVAL_PAGE;
     }
 }

jspwiki-main/src/test/java/org/apache/wiki/ParamTagTest.java

@@ -0,0 +1,147 @@
+/*
+    Licensed to the Apache Software Foundation (ASF) under one
+    or more contributor license agreements.  See the NOTICE file
+    distributed with this work for additional information
+    regarding copyright ownership.  The ASF licenses this file
+    to you under the Apache License, Version 2.0 (the
+    "License"); you may not use this file except in compliance
+    with the License.  You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing,
+    software distributed under the License is distributed on an
+    "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+    KIND, either express or implied.  See the License for the
+    specific language governing permissions and limitations
+    under the License.
+ */
+
+package org.apache.wiki;
+
+import org.apache.wiki.tags.ParamHandler;
+import org.apache.wiki.tags.ParamTag;
+import org.junit.jupiter.api.Test;
+
+import jakarta.servlet.jsp.tagext.BodyContent;
+import jakarta.servlet.jsp.tagext.BodyTagSupport;
+import jakarta.servlet.jsp.tagext.Tag;
+import java.time.Duration;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTimeout;
+import static org.junit.jupiter.api.Assertions.fail;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class ParamTagTest {
+
+
+    @Test
+    public void testDoEndTagWithNonParamHandlerParent() {
+        // Create a mock parent tag that is not a ParamHandler
+        final Tag parentTag = mock(Tag.class);
+        when(parentTag.getParent()).thenReturn(null); // End of the parent chain
+
+        // Create the ParamTag under test and set its parent
+        final ParamTag paramTag = new ParamTag();
+        paramTag.setParent(parentTag);
+
+        // Call the method under test
+        final int result = paramTag.doEndTag();
+
+        // Assert that the method terminated and returned the expected value
+        assertEquals(Tag.EVAL_PAGE, result);
+    }
+
+
+    @Test
+    public void testDoEndTagWithInfiniteLoop() throws Exception {
+        // Create a tag that will cause an infinite loop
+        final Tag parentTag = mock(Tag.class);
+        when(parentTag.getParent()).thenReturn(parentTag);
+
+        final ParamTagOld paramTag = new ParamTagOld();
+        paramTag.setParent(parentTag);
+
+        // Run the code that should cause an infinite loop in a separate thread
+        final ExecutorService executorService = Executors.newSingleThreadExecutor();
+        final Future<Integer> future = executorService.submit(paramTag::doEndTag);
+
+        try {
+            // Allow the test to run for 5 seconds. If it takes longer, consider it an infinite loop.
+            future.get(5, TimeUnit.SECONDS);
+            fail("Expected an infinite loop, but code terminated normally.");
+        } catch (final TimeoutException e) {
+            // This is the expected outcome, as the code should run indefinitely.
+        } finally {
+            // Clean up by shutting down the executor
+            executorService.shutdownNow();
+        }
+    }
+
+    @Test
+    void testNewCodeDoesNotCauseInfiniteLoop() {
+        final ParamTag paramTag = new ParamTag(); // New code class
+
+        final Tag parentTag = mock(Tag.class);
+        when(parentTag.getParent()).thenReturn(parentTag); // Parent returns itself
+
+        paramTag.setParent(parentTag);
+
+        assertTimeout(Duration.ofSeconds(5), () -> {
+            paramTag.doEndTag();
+        }, "Execution should not have taken more than 5 seconds");
+    }
+
+
+    static class ParamTagOld
+            extends BodyTagSupport {
+
+        private static final long serialVersionUID = -4671059568218551633L;
+        private String m_name;
+        private String m_value;
+
+        @Override
+        public void release() {
+            m_name = m_value = null;
+        }
+
+        public void setName(final String s) {
+            m_name = s;
+        }
+
+        public void setValue(final String s) {
+            m_value = s;
+        }
+
+        @Override
+        public int doEndTag() {
+            Tag t;
+            do {
+                t = getParent();
+            } while (t != null && !(t instanceof ParamHandler));
+
+            if (t != null) {
+                String val = m_value;
+                if (val == null) {
+                    final BodyContent bc = getBodyContent();
+                    if (bc != null) {
+                        val = bc.getString();
+                    }
+                }
+                if (val != null) {
+                    ((ParamHandler) t).setContainedParameter(m_name, val);
+                }
+            }
+
+
+            return EVAL_PAGE;
+        }
+    }
+}