From: Yusuke ENDOH <mame@...>
Date: 2008-10-29T21:34:27+09:00
Subject: [ruby-dev:36983] [Bug:1.9] replacing array during sort may make assertion fail

遠藤です。

以下のようにすると assert が失敗します。

$ ./ruby -e 'a = [4,3,2,1]; a.sort! {|x,y| a.replace([]); x <=> y }'
ruby: array.c:1755: rb_ary_sort_bang: Assertion `(((void)
((!((!(((VALUE)(tmp) & RUBY_IMMEDIATE_MASK) || !(((VALUE)(tmp) &
~((VALUE)RUBY_Qnil)) != 0)) && (((struct RBasic*)(tmp))->flags &
RUBY_T_MASK) != RUBY_T_NODE)?(((struct
RBasic*)(tmp))->flags&((((VALUE)1)<<(12+2)))):0) || !((!(((VALUE)(tmp)
& RUBY_IMMEDIATE_MASK) || !(((VALUE)(tmp) & ~((VALUE)RUBY_Qnil)) !=
0)) && (((struct RBasic*)(tmp))->flags & RUBY_T_MASK) !=
RUBY_T_NODE)?(((struct
RBasic*)(tmp))->flags&((((VALUE)1)<<(12+1)))):0)) ? 0 : (__assert_fail
("!((!(((VALUE)(tmp) & RUBY_IMMEDIATE_MASK) || !(((VALUE)(tmp) &
~((VALUE)RUBY_Qnil)) != 0)) && (((struct RBasic*)(tmp))->flags &
RUBY_T_MASK) != RUBY_T_NODE)?(((struct
RBasic*)(tmp))->flags&((((VALUE)1)<<(12+2)))):0) || !((!(((VALUE)(tmp)
& RUBY_IMMEDIATE_MASK) || !(((VALUE)(tmp) & ~((VALUE)RUBY_Qnil)) !=
0)) && (((struct RBasic*)(tmp))->flags & RUBY_T_MASK) !=
RUBY_T_NODE)?(((struct
RBasic*)(tmp))->flags&((((VALUE)1)<<(12+1)))):0)", "array.c", 1755,
__PRETTY_FUNCTION__), 0))), ((!(((VALUE)(tmp) & RUBY_IMMEDIATE_MASK)
|| !(((VALUE)(tmp) & ~((VALUE)RUBY_Qnil)) != 0)) && (((struct
RBasic*)(tmp))->flags & RUBY_T_MASK) != RUBY_T_NODE)?(((struct
RBasic*)(tmp))->flags&((((VALUE)1)<<(12+1)))):0))' failed.
アボートしました


以下の修正でいいでしょうか。

Index: array.c
===================================================================
--- array.c	(revision 20023)
+++ array.c	(working copy)
@@ -1751,14 +1751,14 @@
 	ruby_qsort(RARRAY_PTR(tmp), RARRAY_LEN(tmp), sizeof(VALUE),
 		   rb_block_given_p()?sort_1:sort_2, &data);

-        if (ARY_EMBED_P(ary) || ARY_EMBED_P(tmp)) {
+        if (ARY_EMBED_P(tmp)) {
             assert(ARY_EMBED_P(tmp));
             MEMCPY(RARRAY_PTR(ary), ARY_EMBED_PTR(tmp), VALUE,
ARY_EMBED_LEN(tmp));
             ARY_SET_LEN(ary, ARY_EMBED_LEN(tmp));
         }
         else {
-            assert(!ARY_EMBED_P(ary));
             assert(!ARY_EMBED_P(tmp));
+            if (ARY_EMBED_P(ary)) FL_UNSET_EMBED(ary);
             if (RARRAY_PTR(ary) != RARRAY_PTR(tmp)) {
                 assert(!ARY_SHARED_P(tmp));
                 if (ARY_SHARED_P(ary)) {

-- 
Yusuke ENDOH <mame@tsg.ne.jp>