constify pointer from RARRAY_PTR to detect potential write barrier bugs.

if you see compiler errors due to this commit, you'd better to use array-modifying
functions, e.g. mrb_ary_set() or mrb_ary_push(), otherwise you might see nasty
GC bugs in the future.  if you are sure what you are doing, replace `RARRAY_PTR(ary)`
by `mrb_ary_ptr(ary)->ptr`. but be warned.

1 files changed, 4 insertions, 5 deletions

diff --git a/mrbgems/mruby-random/src/random.c b/mrbgems/mruby-random/src/random.c
index 86c54bc88..3be3ac81c 100644
--- a/mrbgems/mruby-random/src/random.c
+++ b/mrbgems/mruby-random/src/random.c
@@ -221,8 +221,8 @@ mrb_ary_shuffle_bang(mrb_state *mrb, mrb_value ary)
       j = mrb_fixnum(mrb_random_mt_rand(mrb, random, mrb_fixnum_value(RARRAY_LEN(ary))));
 
       tmp = RARRAY_PTR(ary)[i];
-      RARRAY_PTR(ary)[i] = RARRAY_PTR(ary)[j];
-      RARRAY_PTR(ary)[j] = tmp;
+      mrb_ary_ptr(ary)->ptr[i] = RARRAY_PTR(ary)[j];
+      mrb_ary_ptr(ary)->ptr[j] = tmp;
     }
   }
 
@@ -305,11 +305,10 @@ mrb_ary_sample(mrb_state *mrb, mrb_value ary)
         }
         break;
       }
-      RARRAY_PTR(result)[i] = mrb_fixnum_value(r);
-      RARRAY_LEN(result)++;
+      mrb_ary_push(mrb, result, mrb_fixnum_value(r));
     }
     for (i=0; i<n; i++) {
-      RARRAY_PTR(result)[i] = RARRAY_PTR(ary)[mrb_fixnum(RARRAY_PTR(result)[i])];
+      mrb_ary_set(mrb, result, i, RARRAY_PTR(ary)[mrb_fixnum(RARRAY_PTR(result)[i])]);
     }
     return result;
   }