2 files changed, 18 insertions, 2 deletions
diff --git a/ChangeLog b/ChangeLog
index 084e80dd2a..1df3fd10fb 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+Mon Sep 25 08:14:43 2006  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* array.c (rb_ary_shift): should clear shifting top element.
+	  [ruby-talk:216055]
+
+	* array.c (rb_ary_shift): avoid creating shared object if array
+	  size is small.
+
 Mon Sep 25 08:11:35 2006  Yukihiro Matsumoto  <matz@ruby-lang.org>
 
 	* random.c (rb_f_rand): RDoc typo fix.  a patch from Frederick
diff --git a/array.c b/array.c
index 6e6778d68d..6df82f7faa 100644
--- a/array.c
+++ b/array.c
@@ -501,8 +501,16 @@ rb_ary_shift(ary)
     rb_ary_modify_check(ary);
     if (RARRAY(ary)->len == 0) return Qnil;
     top = RARRAY(ary)->ptr[0];
-    ary_make_shared(ary);
-    RARRAY(ary)->ptr++;		/* shift ptr */
+    if (RARRAY_LEN(ary) < ARY_DEFAULT_SIZE) {
+	MEMMOVE(RARRAY_PTR(ary), RARRAY_PTR(ary)+1, VALUE, RARRAY_LEN(ary));
+    }
+    else {
+	if (!FL_TEST(ary, ELTS_SHARED)) {
+	    RARRAY(ary)->ptr[0] = Qnil;
+	}
+	ary_make_shared(ary);
+	RARRAY(ary)->ptr++;		/* shift ptr */
+    }
     RARRAY(ary)->len--;
 
     return top;