[ruby-dev:23228] Zlib::GzipWriter.new(nil).close dumps core

次のように、Zlib::GzipWriter.new(nil).close が core を吐きます。

% ruby -v -rzlib -e 'Zlib::GzipWriter.new(nil).close; p 1'
ruby 1.9.0 (2004-03-25) [i686-linux]
-e:1:in `close': undefined method `write' for nil:NilClass (NoMethodError)
        from -e:1
-e:1: warning: Zlib::GzipWriter object must be closed explicitly.
zsh: segmentation fault (core dumped)  ruby -v -rzlib -e 'Zlib::GzipWriter.new(nil).close; p 1'

[ruby-dev:11915] で触れた話に似ていますが、今回のは明示的に close して
いるので finalizer は関係ありません。にもかかわらず core を吐くのは明
らかによろしくないように思います。

% gdb =ruby core
GNU gdb 5.3-debian
Copyright 2002 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "i386-linux"...
Core was generated by `ruby -v -rzlib -e Zlib::GzipWriter.new(nil).close; p 1'.
Program terminated with signal 11, Segmentation fault.
Reading symbols from /lib/libdl.so.2...done.
Loaded symbols for /lib/libdl.so.2
Reading symbols from /lib/libcrypt.so.1...done.
Loaded symbols for /lib/libcrypt.so.1
Reading symbols from /lib/libm.so.6...done.
Loaded symbols for /lib/libm.so.6
Reading symbols from /lib/libc.so.6...done.
Loaded symbols for /lib/libc.so.6
Reading symbols from /lib/ld-linux.so.2...done.
Loaded symbols for /lib/ld-linux.so.2
Reading symbols from /home/akr/ruby/lib/ruby/1.9/i686-linux/zlib.so...done.
Loaded symbols for /home/akr/ruby/lib/ruby/1.9/i686-linux/zlib.so
Reading symbols from /usr/lib/libz.so.1...done.
Loaded symbols for /usr/lib/libz.so.1
#0  0x401d36e3 in gzfile_writer_end (gz=0x8131988) at zlib.c:2161
2161            if (OBJ_IS_FREED(gz->io)) {
(gdb) bt
#0  0x401d36e3 in gzfile_writer_end (gz=0x8131988) at zlib.c:2161
#1  0x401d2ba2 in gzfile_free (gz=0x8131988) at zlib.c:1711
#2  0x0806e113 in rb_gc_call_finalizer_at_exit () at gc.c:1799
#3  0x080550f9 in ruby_finalize_1 () at eval.c:1397
#4  0x08055220 in ruby_cleanup (ex=1) at eval.c:1434
#5  0x08055358 in ruby_stop (ex=6) at eval.c:1465
#6  0x080553a5 in ruby_run () at eval.c:1477
#7  0x080537e6 in main (argc=5, argv=0xbffff984, envp=0xbffff99c) at main.c:50
#8  0x40084e3e in __libc_start_main () from /lib/libc.so.6
(gdb) 
-- 
[田中 哲][たなか あきら][Tanaka Akira]