Unsafe handling of ArgumentPlaceholders for final classes

[GoogleCodeExporter]

We just came over this issue on our CI server, which executed the tests in a 
different order (Linux filesystem order), compared to our local workstation 
execution W7 filesystem order.

The case comes from an incorrrect lookup af arguments from placeholders of 
final and unknown classes.

The use of ArgumentsFactory.createArgumentPlaceholderForUnknownClass assumes if 
a constructor with a string or numeric value is located, that the equals - 
relation will return false. This is, unfortunately not the case. Consider the 
following case in jodatime:

assertEquals(new LocalDate(Integer.MIN_VALUE),new 
LocalDate(Integer.MIN_VALUE+1));

This actually asserts that the two instances are equal, but the  assumption in 
the code is a unique mapping from argument to invocation-sequence, and in this 
case, the wrong sequence is returned. I believe the assumption that it i safe 
to create a safe placeholder using this approach is flawed and should be 
replaced, possibly with a pluggable factory of placeholder-creators for all 
unknown classes. 

Alternatively, you could add verification-step for unknown classes that 
verifies that two instances created with placeholder-argument Integer.MIN_VALUE 
and Integer.MIN_VALUE +1, and fail with an IllegalArgumentExeption if these two 
placeholders are equal. In this case a pluggable placeholderfactory may be 
provided.

The first test-case depends on Joda time, but I have also provided a version 
with the same property regarding the equals reelation that does not depend on 
Jodatime.

Unfortunately, because of this, we have to restrict lambdaj as a test-only 
dependency, because we consider it to be unsafe in production.

Original issue reported on code.google.com by bjerk...@gmail.com on 20 Jun 2011 at 1:13

Attachments:

• LambdaJArgumentsPlaceholderTest.java
• ArgumentPlaceholderForFinalClassesTest.java

[GoogleCodeExporter]

Starting from lambdaj 2.4 it will be available the static method:

ArgumentsFactory.registerFinalClassArgumentCreator(Class<T> clazz, 
FinalClassArgumentCreator<T> creator)

where FinalClassArgumentCreator is defined as:

public interface FinalClassArgumentCreator<T> {
    T createArgumentPlaceHolder(int seed);
}

Original comment by mario.fu...@gmail.com on 29 Jan 2012 at 5:58

• Changed state: Fixed