Make Array#uniq return subclass instance if called on subclass instance

Previously, Array#uniq would return subclass instance if the
length of the array were 2 or greater, and would return Array
instance if the length of the array were 0 or 1.

Fixes [Bug #7768]

2 files changed, 33 insertions, 4 deletions

diff --git a/array.c b/array.c
index bc5c719267..3717c3ff34 100644
--- a/array.c
+++ b/array.c
@@ -4991,9 +4991,11 @@ rb_ary_uniq(VALUE ary)
 {
     VALUE hash, uniq;
 
-    if (RARRAY_LEN(ary) <= 1)
-        return rb_ary_dup(ary);
-    if (rb_block_given_p()) {
+    if (RARRAY_LEN(ary) <= 1) {
+        hash = 0;
+        uniq = rb_ary_dup(ary);
+    }
+    else if (rb_block_given_p()) {
 	hash = ary_make_hash_by(ary);
 	uniq = rb_hash_values(hash);
     }
@@ -5002,7 +5004,9 @@ rb_ary_uniq(VALUE ary)
 	uniq = rb_hash_values(hash);
     }
     RBASIC_SET_CLASS(uniq, rb_obj_class(ary));
-    ary_recycle_hash(hash);
+    if (hash) {
+        ary_recycle_hash(hash);
+    }
 
     return uniq;
 }
diff --git a/test/ruby/test_array.rb b/test/ruby/test_array.rb
index 05f48abc8e..335c2dc042 100644
--- a/test/ruby/test_array.rb
+++ b/test/ruby/test_array.rb
@@ -1855,6 +1855,31 @@ class TestArray < Test::Unit::TestCase
     ary = [bug9340, bug9340.dup, bug9340.dup]
     assert_equal 1, ary.uniq.size
     assert_same bug9340, ary.uniq[0]
+
+    sc = Class.new(@cls)
+    a = sc[]
+    b = a.dup
+    assert_instance_of(sc, a.uniq)
+    assert_equal(sc[], a.uniq)
+    assert_equal(b, a)
+
+    a = sc[1]
+    b = a.dup
+    assert_instance_of(sc, a.uniq)
+    assert_equal(sc[1], a.uniq)
+    assert_equal(b, a)
+
+    a = sc[1, 1]
+    b = a.dup
+    assert_instance_of(sc, a.uniq)
+    assert_equal(sc[1], a.uniq)
+    assert_equal(b, a)
+
+    a = sc[1, 1]
+    b = a.dup
+    assert_instance_of(sc, a.uniq{|x| x})
+    assert_equal(sc[1], a.uniq{|x| x})
+    assert_equal(b, a)
   end
 
   def test_uniq_with_block