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

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

[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.

[Kenta Murata]

• Assignee set to Hidetoshi Nagai

[Shyouhei Urabe]

• Status changed from Open to Assigned

[Koichi Sasada]

• Target version changed from 2.0.0 to 2.1.0

Time up for 2.0.0.

Nagai-san, how about it?

[Hidetoshi Nagai]

From: "ko1 (Koichi Sasada)" [e-mail]
Subject: [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

[Nobuyoshi Nakada]

• File bug-5199-tkutil.diff View added

Quick patch.

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

[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."

[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.

[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. [Bug #5199]

[Nobuyoshi Nakada]

• Backport set to 2.0.0: REQUIRED

[Tomoyuki Chikanaga]

• Backport changed from 2.0.0: REQUIRED to 2.0.0: DONE

r41351 was backported to ruby_2_0_0 at r44564.