[TAP5-1222] Accessing a public field of a non-component object inside component code can result in a TransfomationException if the accessed field name matches the name of a component field

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 5.2.0
• Fix Version/s: 5.2.1
• Component/s: tapestry-core
• Assignee: Howard Lewis Ship
• Reporter: Howard Lewis Ship
• Created: 26/Jul/10 20:51
• Updated: 31/Aug/10 16:43
• Resolved: 19/Aug/10 21:53

Description

java.lang.ClassNotFoundException
caught an exception while obtaining a class file for com.example.pages.category.CategoryIndex
exception
org.apache.tapestry5.ioc.internal.OperationException: javassist.CannotCompileException: [source error] _$get_category() not found in com.example.data.CategoryTreeNode
org.apache.tapestry5.ioc.internal.OperationException
javassist.CannotCompileException: [source error] _$get_category() not found in com.example.data.CategoryTreeNode
trace
Constructing instance of page class com.example.pages.category.CategoryIndex
Creating ComponentAssembler for com.example.pages.category.CategoryIndex
Transforming component class com.example.pages.category.CategoryIndex
org.apache.tapestry5.internal.services.TransformationException
javassist.CannotCompileException: [source error] _$get_category() not found in com.example.data.CategoryTreeNode

Checking field read category in method $advised$getSubNodesForCurrentNode(): replacing with $ = $0._$get_category();

@Cached(watch = "currentNode")
public List<CategoryTreeNode> getSubNodesForCurrentNode()

{ if (currentNode.category == null) return Collections.emptyList(); return buildNodesForCategory(currentNode.category); }

Because the CategoryIndex page has a field named "category", the transformation attempted to find it's replaced read access method, _$get_category(), in the non-component class (CategoryTreeNode).

The fault is in here:

ExprEditor editor = new ExprEditor()
{
private final Set<CtBehavior> addedMethods = CollectionFactory.newSet();

{
for (TransformMethodImpl tmi : methods.values())

{ if (tmi.added) addedMethods.add(tmi.method); }

}

public void edit(FieldAccess access) throws CannotCompileException
{
CtBehavior where = access.where();

if (where instanceof CtConstructor)
return;

boolean isRead = access.isReader();
String fieldName = access.getFieldName();
CtMethod method = (CtMethod) where;

formatter.format("Checking field %s %s in method %s(): ", isRead ? "read" : "write", fieldName,
method.getName());

// Ignore any methods to were added as part of the transformation.
// If we reference the field there, we really mean the field.

if (addedMethods.contains(where))

{ formatter.format("added method\n"); return; }

Map<String, String> transformMap = isRead ? fieldReadTransforms : fieldWriteTransforms;

String body = transformMap.get(fieldName);
if (body == null)

{ formatter.format("field not transformed\n"); return; }

formatter.format("replacing with %s\n", body);

access.replace(body);
}
};

Have to ensure that the field access is for a field of the component itself.

Issue Links

• is duplicated by: TAP5-1163 ClassTransformation Javassist Compile error accessing public field of non-component class