This equals method is checking wrong operands

Bug: org.eclipse.core.internal.runtime.ReferenceHashSet$HashableSoftReference.equals(Object)
checks for operand being a ReferenceHashSet$HashableWeakReference

This equals method is checking to see if the argument is some
incompatible type (i.e., a class that is neither a supertype nor subtype
of the class that defines the equals method). For example, the Foo class
might have an equals method that looks like:
public boolean equals(Object o) {
    if (o instanceof Foo)
        return name.equals(((Foo)o).name);
    else if (o instanceof String)
        return name.equals(o);
    else return false;
}


This is considered bad practice, as it makes it very hard to implement
an equals method that is symmetric and transitive. Without those
properties, very unexpected behaviors are possible.

Rank: Troubling (14), confidence: High
Pattern: EQ_CHECK_FOR_OPERAND_NOT_COMPATIBLE_WITH_THIS
Type: Eq, Category: BAD_PRACTICE (Bad practice)


Change-Id: I4c9097e9a582c6c936bf3f0b3f8208acaf4f25a8
Signed-off-by: Carsten Hammer <carsten.hammer@t-online.de>

1 files changed, 2 insertions, 2 deletions

diff --git a/bundles/org.eclipse.equinox.common/src/org/eclipse/core/internal/runtime/ReferenceHashSet.java b/bundles/org.eclipse.equinox.common/src/org/eclipse/core/internal/runtime/ReferenceHashSet.java
index 8a17df038..d8b9e77cd 100644
--- a/bundles/org.eclipse.equinox.common/src/org/eclipse/core/internal/runtime/ReferenceHashSet.java
+++ b/bundles/org.eclipse.equinox.common/src/org/eclipse/core/internal/runtime/ReferenceHashSet.java
@@ -74,11 +74,11 @@ public class ReferenceHashSet<T> {
 
 		@Override
 		public boolean equals(Object obj) {
-			if (!(obj instanceof HashableWeakReference))
+			if (!(obj instanceof HashableSoftReference))
 				return false;
 			Object referent = super.get();
 			@SuppressWarnings("unchecked")
-			Object other = ((HashableWeakReference<?>) obj).get();
+			Object other = ((HashableSoftReference<?>) obj).get();
 			if (referent == null)
 				return other == null;
 			return referent.equals(other);