[TAP5-2560] Error in GenericsUtils affecting property access

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 5.4.1
• Fix Version/s: 5.4.5
• Assignee: Thiago Henrique De Paula Figueiredo
• Reporter: Chris Poulsen
• Created: 22/Aug/16 07:11
• Updated: 06/Sep/19 21:59
• Resolved: 06/Sep/19 21:59

Description

There is an error somewhere in the GenericsUtils.resolve( TypeVariable typeVariable, Type containingType ) method.

It resolves some type variables to their lower bound instead of the correct version.

We have model classes that uses lots of generics and in some cases tapestry reports that a given property expression is invalid because some lower bound interface does not contain the property in the expression.

I tried to see if I could find an easy fix, but ended up running out of time and simply replaced the bodies of the 5 resolution methods in the GenericsUtils with guava reflect code and then things started working as expected.

The interface setup that gives the error looks like this:

public interface NonTranslatableContentUnit<T extends ContentData> {
    T getContent();
}

public interface BinaryContentUnit<T extends BinaryContent> extends NonTranslatableContentUnit<T> {}

public interface FileContentUnit extends BinaryContentUnit<FileContent> {}

public interface ContentData {
    isEmpty();
    ...
}

public interface BinaryContent extends ContentData {

    String getMimeType();
    ...
}   

public interface FileContent extends BinaryContent {}

Then we have a property expression on a FileContentUnit like: "content.mimeType" and that fails with an error that says something like ContentData does not have a property MimeType.

As far as I can tell the resolve(TypeVariable, ..) method fails to do anything sensible if the Type of the "containing class" is not an instance of ParameterizedType

Issue Links

• relates to: TAP5-2453 Generic List<T> not fully supported