Bug #9646: Infinite loop at Hash#each

• Status: Closed
• Assignee: -
• Target version: 2.2.0
• ruby -v: ruby 2.0.0p291 (2013-08-11 revision 42493) [x86_64-linux]
• Backport: 2.0.0: DONE, 2.1: DONE

[tarui (Masaya Tarui)]

Hashでキーを同じにすると、無限ループしてしまいます。

再現コードは
ruby -e 'h={};h[a=[]]=1;a<<1;h[[]] = 2;a.clear;h.each{|i| p i}'
です。

st_foreach_checkでcallcc対応のために
find_packed_indexを毎回呼んでおり、そこでiが進まなくなっています。
そもそも、同じキーの状態を作り出せるのがどうなんだという話はあるかもしれませんが、
そちらを直すのは大きな変更になりそうなので、とりあえず以下のような感じでどうでしょうか？
callccでの後戻りをあきらめています。

#または、callccでイテレータの中に戻るのを禁止した方がよいのかもしれません。

--- a/st.c
+++ b/st.c
@@ -394,9 +394,8 @@ find_entry(st_table *table, st_data_t key, st_index_t hash_val, st_index_t bin_p
 }

 static inline st_index_t
-find_packed_index(st_table *table, st_index_t hash_val, st_data_t key)
+find_packed_index_from(st_table *table, st_index_t hash_val, st_data_t key,st_index_t i)
 {
-    st_index_t i = 0;
     while (i < table->real_entries &&
           (PHASH(table, i) != hash_val || !EQUAL(table, key, PKEY(table, i)))) {
        i++;
@@ -404,6 +403,12 @@ find_packed_index(st_table *table, st_index_t hash_val, st_data_t key)
     return i;
 }

+static inline st_index_t
+find_packed_index(st_table *table, st_index_t hash_val, st_data_t key)
+{
+    return find_packed_index_from(table,hash_val,key,0);
+}
+
 #define collision_check 0

 int
@@ -963,8 +968,8 @@ st_foreach_check(st_table *table, int (*func)(ANYARGS), st_data_t arg, st_data_t
                if (PHASH(table, i) == 0 && PKEY(table, i) == never) {
                    break;
                }
-               i = find_packed_index(table, hash, key);
-               if (i == table->real_entries) {
+               i = find_packed_index_from(table, hash, key, i);
+               if (i >= table->real_entries) {
                    goto deleted;
                }
                /* fall through */

[nobu (Nobuyoshi Nakada)]

• Description updated (diff)

[nobu (Nobuyoshi Nakada)]

• Has duplicate Bug #9729: Hash#each が無限ループする added

[tarui (Masaya Tarui)]

• Status changed from Open to Closed
• % Done changed from 0 to 100

Applied in changeset r45642.

---

• st.c (st_foreach_check): chnage start point of search at check
  from top to current. [ruby-dev:48047] [Bug #9646]

[usa (Usaku NAKAMURA)]

• Backport changed from 2.0.0: UNKNOWN, 2.1: UNKNOWN to 2.0.0: REQUIRED, 2.1: REQUIRED

[nagachika (Tomoyuki Chikanaga)]

• Backport changed from 2.0.0: REQUIRED, 2.1: REQUIRED to 2.0.0: REQUIRED, 2.1: DONE

Backported into ruby_2_1 branch at r46721.

[usa (Usaku NAKAMURA)]

• Backport changed from 2.0.0: REQUIRED, 2.1: DONE to 2.0.0: DONE, 2.1: DONE

backported into ruby_2_0_0 at r46747.