[ruby-dev:42072] Re: [Bug #3708] Array#permutation がおかしな結果を返す

むらたです。

On 2010/08/18, at 18:28, Yukihiro Matsumoto wrote:

> |diff --git a/array.c b/array.c
> |index 51d3ad2..ea4fe43 100644
> |--- a/array.c
> |+++ b/array.c
> |@@ -409,10 +409,7 @@ static VALUE
> | ary_make_shared(VALUE ary)
> | {
> |     assert(!ARY_EMBED_P(ary));
> |-    if (ARY_SHARED_P(ary)) {
> |-       return ARY_SHARED(ary);
> |-    }
> |-    else if (ARY_SHARED_ROOT_P(ary)) {
> |+    if (ARY_SHARED_P(ary) || ARY_SHARED_ROOT_P(ary)) {
> |        return ary;
> |     }
> |     else if (OBJ_FROZEN(ary)) {
> 
> なるほど。コミットして下さい。
> 


一旦これでコミットしたのですが、SEGV が発生することがあったため revert しました。

なかださんに ary_make_shared_copy を教えてもらったので、もう一度修正案を提示します。
repeated_permutation、repeated_combination、product も対象です。

diff --git a/array.c b/array.c
index 51d3ad2..bca7956 100644
--- a/array.c
+++ b/array.c
@@ -4010,7 +4010,7 @@ rb_ary_permutation(int argc, VALUE *argv, VALUE ary)
        long *p = (long*)RSTRING_PTR(t0);
        volatile VALUE t1 = tmpbuf(n,sizeof(char));
        char *used = (char*)RSTRING_PTR(t1);
-       VALUE ary0 = ary_make_substitution(ary); /* private defensive copy of ary */
+       VALUE ary0 = ary_make_shared_copy(ary); /* private defensive copy of ary */
        RBASIC(ary0)->klass = 0;

        MEMZERO(used, char, n); /* initialize array */
@@ -4180,7 +4180,7 @@ rb_ary_repeated_permutation(VALUE ary, VALUE num)
     else {             /* this is the general case */
        volatile VALUE t0 = tmpbuf(r, sizeof(long));
        long *p = (long*)RSTRING_PTR(t0);
-       VALUE ary0 = ary_make_substitution(ary); /* private defensive copy of ary */
+       VALUE ary0 = ary_make_shared_copy(ary); /* private defensive copy of ary */
        RBASIC(ary0)->klass = 0;

        rpermute0(n, r, p, 0, ary0); /* compute and yield repeated permutations */
@@ -4266,7 +4266,7 @@ rb_ary_repeated_combination(VALUE ary, VALUE num)
     else {
        volatile VALUE t0 = tmpbuf(n, sizeof(long));
        long *p = (long*)RSTRING_PTR(t0);
-       VALUE ary0 = ary_make_substitution(ary); /* private defensive copy of ary */
+       VALUE ary0 = ary_make_shared_copy(ary); /* private defensive copy of ary */
        RBASIC(ary0)->klass = 0;

        rcombinate0(len, n, p, 0, n, ary0); /* compute and yield repeated combinations */
@@ -4325,7 +4325,7 @@ rb_ary_product(int argc, VALUE *argv, VALUE ary)
        /* Make defensive copies of arrays; exit if any is empty */
        for (i = 0; i < n; i++) {
            if (RARRAY_LEN(arrays[i]) == 0) goto done;
-           arrays[i] = ary_make_substitution(arrays[i]);
+           arrays[i] = ary_make_shared_copy(arrays[i]);
        }
     }
     else {
--- a/test/ruby/test_array.rb
+++ b/test/ruby/test_array.rb
@@ -1528,6 +1528,10 @@ class TestArray < Test::Unit::TestCase
     acc = [1,2].product(*[o]*10)
     assert_equal([1,2].product([3,4], [3,4], [3,4], [3,4], [3,4], [3,4], [3,4], [3,4], [3,4], [3,4]),
                  acc)
+
+    a = []
+    [1, 2].product([0, 1, 2, 3, 4][1, 4]) {|x| a << x }
+    assert(a.all?{|x| !x.include?(0) })
   end

   def test_permutation
@@ -1574,6 +1578,9 @@ class TestArray < Test::Unit::TestCase
     a.repeated_permutation(4) {|x| b << x; a.replace(@cls[9, 8, 7, 6]) }
     assert_equal(@cls[9, 8, 7, 6], a)
     assert_equal(@cls[1, 2, 3, 4].repeated_permutation(4).to_a, b)
+
+    a = @cls[0, 1, 2, 3, 4][1, 4].repeated_permutation(2)
+    assert(a.all?{|x| !x.include?(0) })
   end

   def test_repeated_combination
@@ -1600,6 +1607,9 @@ class TestArray < Test::Unit::TestCase
     a.repeated_combination(4) {|x| b << x; a.replace(@cls[9, 8, 7, 6]) }
     assert_equal(@cls[9, 8, 7, 6], a)
     assert_equal(@cls[1, 2, 3, 4].repeated_combination(4).to_a, b)
+
+    a = @cls[0, 1, 2, 3, 4][1, 4].repeated_combination(2)
+    assert(a.all?{|x| !x.include?(0) })
   end

   def test_take


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