Narrow simulated Fixnum identity to fixnum range

headius · headius · commit a3f96bd2d8b1 · 2021-02-01T12:49:41.000-06:00
In CRuby, only integer values within the valid range for fixnum
tagged pointers are considered identical. JRuby considered all
Fixnum objects identical. This commit narows the JRuby identity
logic to only values within the fixnum tagged pointer range.
diff --git a/core/src/main/java/org/jruby/RubyFixnum.java b/core/src/main/java/org/jruby/RubyFixnum.java
@@ -155,7 +155,23 @@ public final boolean eql(IRubyObject other) {
 
     @Override
     public IRubyObject equal_p(ThreadContext context, IRubyObject obj) {
-        return RubyBoolean.newBoolean(context, this == obj || eql(obj));
+        long value = this.value;
+
+        if (fixnumable(value)) {
+            return RubyBoolean.newBoolean(context, this == obj || eql(obj));
+        }
+
+        return super.equal_p(context, obj);
+    }
+
+    /**
+     * Determine whether the given long value is in fixnum range.
+     *
+     * @param value the value in question
+     * @return true if the value is in fixnum range, false otherwise
+     */
+    private static boolean fixnumable(long value) {
+        return value <= Long.MAX_VALUE / 2 && value >= Long.MIN_VALUE / 2;
     }
 
     @Override
@@ -1386,7 +1402,9 @@ public IRubyObject bit_length(ThreadContext context) {
 
     @Override
     public IRubyObject id() {
-        if (value <= Long.MAX_VALUE / 2 && value >= Long.MIN_VALUE / 2) {
+        long value = this.value;
+
+        if (fixnumable(value)) {
             return newFixnum(metaClass.runtime, 2 * value + 1);
         }
 
