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Bug 347021

Summary:	NPE hovering in half broken program
Product:	[Tools] AJDT	Reporter:	Andrew Clement <aclement>
Component:	UI	Assignee:	AJDT-inbox <AJDT-inbox>
Status:	RESOLVED FIXED	QA Contact:
Severity:	normal
Priority:	P3
Version:	2.1.2
Target Milestone:	2.1.3
Hardware:	PC
OS:	Mac OS X - Carbon (unsup.)
Whiteboard:

Description Andrew Clement

2011-05-24 12:57:50 EDT

Hovering over 'Fun1' in the map ITD, i get:


java.lang.NullPointerException
	at org.eclipse.ajdt.core.text.ITDAwareSelectionRequestor.acceptType(ITDAwareSelectionRequestor.java:286)
	at org.eclipse.jdt.internal.codeassist.SelectionEngine.selectFrom(SelectionEngine.java:1098)
	at org.eclipse.jdt.internal.codeassist.SelectionEngine.select(SelectionEngine.java:938)
	at org.eclipse.ajdt.core.text.ITDCodeSelection.findJavaElement(ITDCodeSelection.java:97)
	at org.eclipse.ajdt.internal.core.contentassist.ContentAssistProvider.doCodeSelect(ContentAssistProvider.java:167)
	at org.eclipse.jdt.internal.core.CompilationUnit.codeSelect_aroundBody1$advice(CompilationUnit.java:317)
	at org.eclipse.jdt.internal.core.CompilationUnit.codeSelect(CompilationUnit.java:1)
	at org.eclipse.jdt.internal.ui.text.java.hover.AbstractJavaEditorTextHover.getJavaElementsAt(AbstractJavaEditorTextHover.java:115)
	at org.codehaus.groovy.eclipse.editor.GroovyExtraInformationHover.getHoverInfo2(GroovyExtraInformationHover.java:39)
	at org.eclipse.jdt.internal.ui.text.java.hover.BestMatchHover.getHoverInfo2(BestMatchHover.java:141)
	at org.eclipse.jdt.internal.ui.text.java.hover.JavaEditorTextHoverProxy.getHoverInfo2(JavaEditorTextHoverProxy.java:82)
	at org.eclipse.jface.text.TextViewerHoverManager$4.run(TextViewerHoverManager.java:166)

This is IterableAspect.aj:
===
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;


class C implements Iterable<String> {

	@Override
	public Iterator<String> iterator() {
		return null;
	}
	
} 

abstract aspect IterableAspect<T> pertypewithin(Iterable<T>+){
	
	interface Fun1<T,R> {
		R apply(T param);
	}

	public <R> Collection<R> Iterable.map(Fun1<T,R> fun) {
		Collection<R> result=new ArrayList<R>();
		for (T value : this) {
			result.add(fun.apply(value));
		}
		return result;
	}
}

===

Comment 1 Andrew Eisenberg

2011-05-30 19:57:56 EDT

Looks like there are several problems here.

First, this class still has 'this' with a spurious error:

import java.util.Iterator;
class C implements Iterable<String> {
	public Iterator<String> iterator() {
		return null;
	}
}

abstract aspect IterableAspect {

	public void C.map() {
		for (String value : this) {
		}
	}
}

Second, the NPE that you are seeing is happening because AJDT is getting tripped up in some code that is looking for ITITs.  This is easy enough to fix.

Third, it doesn't look like the type parameters in the ITD are being applied to Iterable.

Comment 2 Andrew Eisenberg

2011-06-10 18:30:10 EDT

The NPE has now been fixed, but I am keeping this bug open because of the other problems that it has uncovered.

Comment 3 Andrew Eisenberg

2011-06-10 19:06:35 EDT

OK.  For the spurious error, I have a solution.  We will ignore all type errors when the target expression is 'this' and we are inside ITDs.  Ignoring these errors in these situations is narrow enough that we shouldn't get into trouble.

I have the implementaiton locally, but need to write some tests before I commit.

Comment 4 Andrew Eisenberg

2011-06-11 01:31:24 EDT

Now fixed.  Committed with regression tests.