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Bug #3016

Enumerable#slice_before and dup

Added by marcandre (Marc-Andre Lafortune) over 9 years ago. Updated about 8 years ago.

Status:
Rejected
Priority:
Normal
Assignee:
-
Target version:
ruby -v:
ruby 1.9.2dev (2010-03-03 trunk 26805) [x86_64-darwin10.2.0]
Backport:
[ruby-core:29026]

Description

=begin
When writing the specs for slice_before, I was surprised that it doesn't call #dup.

class X
def dup
raise "Hi!"
end
end

[:foo].slice_before(X.new){}.to_a
# ==> :foo, I expected it to raise

The implementation calls directly rb_obj_dup.

It's a minor issue, but would it not be best to call dup on the argument? Most special needs for #dup can be addressed by initialize_dup, but maybe there are some reasonable cases where some user classes will redefine #dup?

The same question is valid for Enumerable#chunk.

diff --git a/enum.c b/enum.c
index b69d8c9..e6e6adb 100644
--- a/enum.c
+++ b/enum.c
@@ -14,7 +14,7 @@
#include "node.h"

VALUE rb_mEnumerable;
-static ID id_each, id_eqq, id_cmp, id_next, id_size;
+static ID id_each, id_eqq, id_cmp, id_next, id_size, id_dup;

static VALUE
enum_values_pack(int argc, VALUE *argv)
@@ -2189,7 +2189,7 @@ chunk_i(VALUE yielder, VALUE enumerator, int argc, VALUE *argv)
arg.yielder = yielder;

  if (!NIL_P(arg.state))
  • arg.state = rb_obj_dup(arg.state);
  •    arg.state = rb_funcall(arg.state, id_dup, 0, 0);
    

    rb_block_call(enumerable, id_each, 0, 0, chunk_ii, (VALUE)&arg);
    if (!NIL_P(arg.prev_elts))
    @@ -2364,7 +2364,7 @@ slicebefore_i(VALUE yielder, VALUE enumerator, int argc, VALUE *argv)
    arg.yielder = yielder;

    if (!NIL_P(arg.state))

  •    arg.state = rb_obj_dup(arg.state);
    
  •    arg.state = rb_funcall(arg.state, id_dup, 0, 0);
    

    rb_block_call(enumerable, id_each, 0, 0, slicebefore_ii, (VALUE)&arg);
    if (!NIL_P(arg.prev_elts))
    @@ -2606,5 +2606,6 @@ Init_Enumerable(void)
    id_cmp = rb_intern("<=>");
    id_next = rb_intern("next");
    id_size = rb_intern("size");

  • id_dup = rb_intern("dup");
    }
    =end

History

#1

Updated by matz (Yukihiro Matsumoto) over 9 years ago

=begin
Hi,

In message "Re: [ruby-core:29026] [Bug #3016] Enumerable#slice_before and dup"
on Fri, 26 Mar 2010 14:02:05 +0900, Marc-Andre Lafortune redmine@ruby-lang.org writes:

|When writing the specs for slice_before, I was surprised that it doesn't call #dup.

MRI often bypasses method calls using direct C function call, mostly
for performance reason. I am afraid that it's too late to fix all
"surprises". I say it's implementation dependent behavior. I think
it is over specification to check.

                        matz.

=end

#2

Updated by mame (Yusuke Endoh) about 9 years ago

  • Status changed from Open to Rejected

=begin
Hi,

This ticket is rejected by matz.
So closed.

--
Yusuke Endoh mame@tsg.ne.jp
=end

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