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XRENDERING-771: Null pointer exception when list items occur without lists #327

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Merged
michitux merged 2 commits into from
Jul 3, 2025
Merged

XRENDERING-771: Null pointer exception when list items occur without lists #327

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XRENDERING-771: Null pointer exception when list items occur without …
michitux Jan 23, 2025
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XRENDERING-771: Null pointer exception when list items occur without …
michitux Feb 27, 2025
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16 changes: 16 additions & 0 deletions ...g-api/src/main/java/org/xwiki/rendering/listener/chaining/BlockStateChainingListener.java
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Original file line number Diff line number Diff line change
Expand Up @@ -278,6 +278,10 @@ public void beginDocument(MetaData metadata)
public void beginDefinitionDescription()
{
++this.inlineDepth;
if (this.definitionListDepth.isEmpty()) {
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@surli surli Jan 24, 2025

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Why not encapsulating the content of the method in an if (!this.definitionListDepth.isEmpty()) { instead of adding artificially an element? Would that break something else?

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@michitux michitux Jan 24, 2025

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Hm, I thought so, but now I'm not so sure anymore. It seems that getListItemIndex already checks if the stack is non-empty, so this might actually be a better solution... It will break the printing of the list items in both XWiki syntax and plain text, but it might be cleaner.

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@surli surli Jan 24, 2025

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And +1 for having a warning in the else branch then.

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@michitux michitux Feb 27, 2025 •
edited
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I've adjusted the code. I've decided not to log a warning as it is hard to provide relevant information for admins to perform any actions, in particular without a stack trace. For now, I'm just logging a debug message. A possibility could also be to make this a warning when deprecation logging is enabled as in https://github.com/xwiki/xwiki-platform/blob/05d353688490b416a90fcf9ba116cca04e8a9b06/xwiki-platform-core/xwiki-platform-oldcore/src/main/java/com/xpn/xwiki/doc/XWikiDocument.java#L2434-L2437 but to me that doesn't really seem fitting, what do you think?

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@tmortagne tmortagne Feb 27, 2025

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to me that doesn't really seem fitting

Yeah, does not feel like a deprecation. In the case of cache document modification, I used it because modifying directly the cached document used to be kind of officially OK.

// Avoid a null pointer exception. The result might be wrong but at least it won't break.
this.definitionListDepth.push(new DefinitionListState());
}
++this.definitionListDepth.peek().definitionListItemIndex;

super.beginDefinitionDescription();
Expand All @@ -304,6 +308,10 @@ public void beginDefinitionList(Map<String, String> parameters)
public void beginDefinitionTerm()
{
++this.inlineDepth;
if (this.definitionListDepth.isEmpty()) {
// Avoid a null pointer exception. The result might be wrong but at least it won't break.
this.definitionListDepth.push(new DefinitionListState());
}
++this.definitionListDepth.peek().definitionListItemIndex;

super.beginDefinitionTerm();
Expand Down Expand Up @@ -340,6 +348,10 @@ public void beginList(ListType type, Map<String, String> parameters)
public void beginListItem()
{
++this.inlineDepth;
if (this.listDepth.isEmpty()) {
// Avoid a null pointer exception. The result might be wrong but at least it won't break.
this.listDepth.push(new ListState());
}
++this.listDepth.peek().listItemIndex;

super.beginListItem();
Expand All @@ -351,6 +363,10 @@ public void beginListItem()
public void beginListItem(Map<String, String> parameters)
{
++this.inlineDepth;
if (this.listDepth.isEmpty()) {
// Avoid a null pointer exception. The result might be wrong but at least it won't break.
this.listDepth.push(new ListState());
}
++this.listDepth.peek().listItemIndex;

super.beginListItem(parameters);
Expand Down
46 changes: 46 additions & 0 deletions ...i/src/test/java/org/xwiki/rendering/listener/chaining/BlockStateChainingListenerTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -21,11 +21,13 @@

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Map;

import org.apache.commons.text.CaseUtils;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.MethodSource;
import org.junit.jupiter.params.provider.ValueSource;
import org.mockito.stubbing.Stubber;
import org.xwiki.rendering.listener.ListType;
import org.xwiki.rendering.listener.Listener;
Expand All @@ -34,6 +36,7 @@
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNotNull;
import static org.junit.jupiter.api.Assertions.assertNull;
import static org.junit.jupiter.api.Assertions.assertTrue;
import static org.mockito.Mockito.doAnswer;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.verify;
Expand Down Expand Up @@ -188,4 +191,47 @@ void testOnMethod(Method method, Object[] parameters) throws InvocationTargetExc

this.listener.endDocument(MetaData.EMPTY);
}

@ParameterizedTest
@ValueSource(booleans = { true, false })
void testListItemWithoutParent(boolean withParameter) throws Exception
{
Class<?>[] parameterTypes = withParameter ? new Class<?>[] { Map.class } : new Class<?>[0];
Method beginMethod = BlockStateChainingListener.class.getDeclaredMethod("beginListItem", parameterTypes);
Method endMethod = BlockStateChainingListener.class.getDeclaredMethod("endListItem", parameterTypes);
Object[] parameters = withParameter ? new Object[] { Listener.EMPTY_PARAMETERS } : new Object[0];

this.listener.beginDocument(MetaData.EMPTY);
beginMethod.invoke(this.listener, parameters);
assertEquals(0, this.listener.getListItemIndex());
assertTrue(this.listener.isInList());
assertEquals(1, this.listener.getListDepth());
endMethod.invoke(this.listener, parameters);
beginMethod.invoke(this.listener, parameters);
assertEquals(1, this.listener.getListItemIndex());
assertTrue(this.listener.isInList());
assertEquals(1, this.listener.getListDepth());
endMethod.invoke(this.listener, parameters);
this.listener.endDocument(MetaData.EMPTY);
}

@ParameterizedTest
@ValueSource(strings = { "Term", "Description" })
void testDefinitionListItemWithoutParent(String methodSuffix) throws Exception
{
Method beginMethod = BlockStateChainingListener.class.getDeclaredMethod("beginDefinition" + methodSuffix);
Method endMethod = BlockStateChainingListener.class.getDeclaredMethod("endDefinition" + methodSuffix);
this.listener.beginDocument(MetaData.EMPTY);
beginMethod.invoke(this.listener);
assertTrue(this.listener.isInDefinitionList());
assertEquals(0, this.listener.getDefinitionListItemIndex());
assertEquals(1, this.listener.getDefinitionListDepth());
endMethod.invoke(this.listener);
beginMethod.invoke(this.listener);
assertTrue(this.listener.isInDefinitionList());
assertEquals(1, this.listener.getDefinitionListItemIndex());
assertEquals(1, this.listener.getDefinitionListDepth());
endMethod.invoke(this.listener);
this.listener.endDocument(MetaData.EMPTY);
}
}