[GR-20446] Fixed ENV.replace spec issues.

PullRequest: truffleruby/1252

Author: bjfish

CHANGELOG.md

@@ -66,6 +66,7 @@ Bug fixes:
 * Fixed parameter conversion to `String` in ENV methods.
 * Fixed deprecation warning when `ENV.index` is called.
 * Fixed issue with `ENV.each_key`.
+* Fixed `ENV.replace` implementation.
 
 Compatibility:
 

spec/tags/core/env/replace_tags.txt

@@ -243,8 +243,15 @@ def rehash
   end
 
   def replace(other)
-    clear
-    other.each { |k, v| self[k] = v }
+    return self if equal?(other)
+    other = Truffle::Type.rb_convert_type(other, Hash, :to_hash)
+    keys_to_delete = keys
+    other.each do |k, v|
+      self[k] = v
+      keys_to_delete.delete(k)
+    end
+    keys_to_delete.each { |k| delete(k) }
+    self
   end
 
   def select(&blk)