Bug #5199: ext/tk: RB_GC_GUARD seems to be needed in several places

• Status: Closed
• Priority: Normal
• Assignee: nagai (Hidetoshi Nagai)
• Target version: 2.1.0
• ruby -v: ruby 1.9.4dev (2011-08-11 trunk 32931) [x86_64-linux]
• Backport: 2.0.0: DONE

[normalperson (Eric Wong)]

I noticed the following in ext/tk/tkutil/tkutil.c:

rb_warning("fail to convert '%s' to string for Tk",
               RSTRING_PTR(rb_funcall(obj, rb_intern("inspect"), 0,
               0)));

id = rb_intern(RSTRING_PTR(rb_str_cat2(rb_str_new2("@"), str)));

I don't use or know the Tk ext at all, but the above examples do not
appear safe from a GC perspective. Compilers can optimize the original
VALUE away entirely so GC can collect.

RSTRING_PTR (being a macro,) may also evaluate its arguments multiple
times.

[mrkn (Kenta Murata)]

• Assignee set to nagai (Hidetoshi Nagai)

[shyouhei (Shyouhei Urabe)]

• Status changed from Open to Assigned

[ko1 (Koichi Sasada)]

• Target version changed from 2.0.0 to 2.1.0

Time up for 2.0.0.

Nagai-san, how about it?

[nagai (Hidetoshi Nagai)]

From: "ko1 (Koichi Sasada)" [e-mail]
Subject: [ruby-core:52367] [ruby-trunk - Bug #5199] ext/tk: RB_GC_GUARD seems to be needed in several places
Date: Sun, 17 Feb 2013 19:06:43 +0900
Message-ID: [e-mail]

Issue #5199 has been updated by ko1 (Koichi Sasada).

Target version changed from 2.0.0 to 2.1.0

Time up for 2.0.0.

Nagai-san, how about it?

I'm very sorry. I didn't check the tickets about Ruby/Tk.
Last half year (and now), I was busy on my primary works.
So I couldn't follow up many changes for 2.0.0.
I'll fix them on 2.1.0 as soon as possible.
Although I'm sorry, it's not now. Maybe, it is one month or more after.

Hidetoshi NAGAI ([e-mail])
Department of Artificial Intelligence, Kyushu Institute of Technology

[nobu (Nobuyoshi Nakada)]

• File bug-5199-tkutil.diff bug-5199-tkutil.diff added

Quick patch.

2.0 has GC safe functions, rb_sprintf() with PRIsVALUE, rb_intern_str(), and so on.

[jonforums (Jon Forums)]

nobu (Nobuyoshi Nakada) wrote:

Quick patch.

2.0 has GC safe functions, rb_sprintf() with PRIsVALUE, rb_intern_str(), and so on.

Does a list of these new 2.0 GC-safe functions exist anywhere?

If the 2.0 GC-safe functions aren't currently enumerated in a single, accessible place, should they be listed in a new section to README.EXT, and a short note added to mame-san's draft 2.0.0-p0 ANN? Perhaps under "Built-in libraries" as "New GC-safe API for more robust extensions."

[nagai (Hidetoshi Nagai)]

nobu (Nobuyoshi Nakada) wrote:

Quick patch.

2.0 has GC safe functions, rb_sprintf() with PRIsVALUE, rb_intern_str(), and so on.

Nakada-san, please commit the patch.

[nobu (Nobuyoshi Nakada)]

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

This issue was solved with changeset r41351.
Eric, thank you for reporting this issue.
Your contribution to Ruby is greatly appreciated.
May Ruby be with you.

---

tkutil.c: prevent temporary objects from GC

• ext/tk/tkutil/tkutil.c: use rb_sprintf(), rb_id2str(), and
  rb_intern_str() instead of rb_intern() and RSTRING_PTR() with
  RB_GC_GUARD(), to prevent temporary objects from GC.
  [ruby-core:39000] [Bug #5199]

[nobu (Nobuyoshi Nakada)]

• Backport set to 2.0.0: REQUIRED

[nagachika (Tomoyuki Chikanaga)]

• Backport changed from 2.0.0: REQUIRED to 2.0.0: DONE

r41351 was backported to ruby_2_0_0 at r44564.