Recursion detection should use identity map, but it blows up #3887
Description
I believe our "execRecursive" logic (mostly ported from MRI) should be using an identity hash. This appears to be what MRI does, and it makes sense since calculating a full hash during a recursive walk could be O(something really big).
However, when I attempted to apply the following patch, recursion detection seemed to break altogether:
diff --git a/core/src/main/java/org/jruby/Ruby.java b/core/src/main/java/org/jruby/Ruby.java
index 10bcba2..d490770 100644
--- a/core/src/main/java/org/jruby/Ruby.java
+++ b/core/src/main/java/org/jruby/Ruby.java
@@ -4310,7 +4310,7 @@ public final class Ruby implements Constantizable {
list = hash.get(sym);
}
if(list == null || list.isNil()) {
- list = RubyHash.newHash(this);
+ list = RubyHash.newIdentityHash(this);
hash.put(sym, (RubyHash)list);
}
return list;
diff --git a/core/src/main/java/org/jruby/RubyHash.java b/core/src/main/java/org/jruby/RubyHash.java
index 9627915..89ff9b2 100644
--- a/core/src/main/java/org/jruby/RubyHash.java
+++ b/core/src/main/java/org/jruby/RubyHash.java
@@ -223,6 +223,13 @@ public class RubyHash extends RubyObject implements Map {
return new RubyHash(runtime, valueMap, defaultValue);
}
+ // MRI: rb_ident_hash_new
+ public static final RubyHash newIdentityHash(Ruby runtime) {
+ RubyHash identityHash = new RubyHash(runtime);
+ identityHash.setComparedByIdentity(true);
+ return identityHash;
+ }
+
private RubyHashEntry[] table;
protected int size = 0;
private int threshold;We really need to fix this up the right way.