# \[Bug #651\] Regexp.new returns strange regexp object

**URL:** <https://www.ruby-forum.com/t/bug-651-regexp-new-returns-strange-regexp-object/151006>\
**Category:** Development\
**Created:** [October 15, 2008, 8:32pm UTC](https://www.ruby-forum.com/t/bug-651-regexp-new-returns-strange-regexp-object/151006 "2008-10-15T20:32:39Z")\
**Posts on this page:** 7\
**Page:** 1

<div class="post-metadata">

**Author:** ![Shyouhei\_U](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/94ad74/32.png) [@Shyouhei\_U](https://www.ruby-forum.com/u/Shyouhei_U)\
**Post date:** [October 15, 2008, 8:32pm UTC](https://www.ruby-forum.com/t/bug-651-regexp-new-returns-strange-regexp-object/151006/1 "2008-10-15T20:32:39Z")

</div>

Bug #651: Regexp.new returns strange regexp object  
[http://redmine.ruby-lang.org/issues/show/651](http://redmine.ruby-lang.org/issues/show/651)

e$B5/I\<\<Te(B: Shyouhei U.  
e$B%9%F!\<%?%9e(B: Open, e$BM%@hEYe(B: Normal  
e$BC4Ev\<Te(B: Yukihiro M.

e$B0J2\<$N$h$&$JEy\<0$,@.N)$7$J$/$J$C$?$3$H$K5$$E$-$^$7$?!#e(B

% ruby1.9 -e ‘p( //u == Regexp.new(“”, nil, “u”) )’  
false

---

<div class="post-metadata">

**Author:** ![Shyouhei\_U](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/94ad74/32.png) [@Shyouhei\_U](https://www.ruby-forum.com/u/Shyouhei_U)\
**Post date:** [October 16, 2008, 3:14am UTC](https://www.ruby-forum.com/t/bug-651-regexp-new-returns-strange-regexp-object/151006/2 "2008-10-16T03:14:20Z")

</div>

e$B$^$D$b$He(B e$B$f$-$R$m$G$9e(B

In message “Re: [ruby-dev:36753] [Bug #651] Regexp.new returns strange  
regexp object”  
on Thu, 16 Oct 2008 03:31:52 +0900, Shyouhei U.  
[removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) writes:

|e$B0J2\<$N$h$&$JEy\<0$,@.N)$7$J$/$J$C$?$3$H$K5$$E$-$^$7$?!#e(B  
|  
| % ruby1.9 -e ‘p( //u == Regexp.new(“”, nil, “u”) )’  
| false

e$B$3$l$Oe(B1.9e$B$+$i;0HVL$N0z?t$,L5;k$5$l$k$3$H$K$J$C$?$;$$$G$9!#e(B  
e$B$=$N$;$$$G!"e(BRegexp.newe$B$,@8@.$7$?$b$N$Oe(BUTF-8e$B8GDj$G$O$J$/$J$Ce(B  
e$B$F$^$9!#e(B

e$B$,!"IT?F@Z$J$N$O3N$+$J$N$G!"e(B

- -v e$B$,$J$/$F$b7Y9p$9$ke(B
- e$B%a%C%;!\<%8$re(Bobsoletee$B$+$ie(Bignorede$B$KJQ99$9$ke(B

e$B$H$$$&BP1~$K$7$h$&$H;W$$$^$9!#JL$N0F$H$7$F$O!"e(B

- 'u’e$BBP1~$rI|3h$5$;$ke(B

e$B$H$$$&$b$N$b$"$j$($^$9$,!#e(B

---

<div class="post-metadata">

**Author:** ![Shyouhei\_U](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/94ad74/32.png) [@Shyouhei\_U](https://www.ruby-forum.com/u/Shyouhei_U)\
**Post date:** [October 17, 2008, 12:38am UTC](https://www.ruby-forum.com/t/bug-651-regexp-new-returns-strange-regexp-object/151006/3 "2008-10-17T00:38:22Z")

</div>

e$B$^$D$b$He(B e$B$f$-$R$m$G$9e(B

In message “Re: [ruby-dev:36755] Re: [Bug #651] Regexp.new returns  
strange regexp object”  
on Thu, 16 Oct 2008 14:18:48 +0900, Urabe S.  
[removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) writes:

|\> e$B$,!"IT?F@Z$J$N$O3N$+$J$N$G!"e(B  
|\>  
|\> \* -v e$B$,$J$/$F$b7Y9p$9$ke(B  
|\> \* e$B%a%C%;!\<%8$re(Bobsoletee$B$+$ie(Bignorede$B$KJQ99$9$ke(B  
|\>  
|\> e$B$H$$$&BP1~$K$7$h$&$H;W$$$^$9!#e(B  
|  
|e$BBEEv$G$O$J$$$G$7$g$&$+!#e(B

e$B$H$O$$$(!“!V%(%s%I%f!\<%6$,7Y9p$r8+$F$b:$OG$9$k$@$1!W$H$$$&;Xe(B  
e$BE&$b$”$j!"G:$^$7$$$H$3$m$G$9!#e(B

|ruby -Kn -e ‘p “\xF0\x80\x80\xBC”.match(Regexp.new(“.”, nil, “u”))’  
|#\<MatchData “\xF0”\>  
|  
|e$B$"$?$j$O;v\>p$rCN$i$J$$$H$S$C$/$j$7$^$9!#7Y9p$/$i$$$O=P$F$b$$$$$H;W$$$^$9!#e(B

e$B$=$&$G$9$M$(!#e(B

|\> e$BJL$N0F$H$7$F$O!“e(B  
|\>  
|\> \* 'u’e$BBP1~$rI|3h$5$;$ke(B  
|\>  
|\> e$B$H$$$&$b$N$b$”$j$($^$9$,!#e(B  
|\>  
|ue$B$H$+e(Bee$B$O$H$b$+$/e(Bne$B$,M\_$7$$$3$H$O$"$k$s$8$c$J$$$G$9$+$M$(!#e(B

e$B$"!“e(Bne$B$O$”$$$+$o$i$:M-8z$G$9!#L5;k$5$l$k$h$&$K$J$C$?$N$Oe(Bne$B0J30e(B  
e$B$Ne(Bee$B$H$+e(Bse$B$H$+e(Bue$B$H$+$G$9!#e(B

---

<div class="post-metadata">

**Author:** ![Shyouhei\_U](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/94ad74/32.png) [@Shyouhei\_U](https://www.ruby-forum.com/u/Shyouhei_U)\
**Post date:** [October 17, 2008, 12:47am UTC](https://www.ruby-forum.com/t/bug-651-regexp-new-returns-strange-regexp-object/151006/4 "2008-10-17T00:47:44Z")

</div>

e$B%A%1%C%He(B #651 e$B$,99?7$5$l$^$7$?!#e(B (by Yukihiro M.)

e$B%9%F!\<%?%9e(B Opene$B$+$ie(BClosede$B$KJQ99e(B  
e$B?JD=e(B % 0e$B$+$ie(B100e$B$KJQ99e(B

## Applied in changeset r19813.

[http://redmine.ruby-lang.org/issues/show/651](http://redmine.ruby-lang.org/issues/show/651)

---

<div class="post-metadata">

**Author:** ![Shyouhei\_U](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/94ad74/32.png) [@Shyouhei\_U](https://www.ruby-forum.com/u/Shyouhei_U)\
**Post date:** [October 16, 2008, 7:19am UTC](https://www.ruby-forum.com/t/bug-651-regexp-new-returns-strange-regexp-object/151006/5 "2008-10-16T07:19:56Z")

</div>

e$BKNIt$G$9e(B

Yukihiro M. e$B$5$s$O=q$-$^$7$?e(B:

> e$B$3$l$Oe(B1.9e$B$+$i;0HVL$N0z?t$,L5;k$5$l$k$3$H$K$J$C$?$;$$$G$9!#e(B  
> e$B$=$N$;$$$G!"e(BRegexp.newe$B$,@8@.$7$?$b$N$Oe(BUTF-8e$B8GDj$G$O$J$/$J$Ce(B  
> e$B$F$^$9!#e(B
> 
> e$B$,!"IT?F@Z$J$N$O3N$+$J$N$G!"e(B
> 
> - -v e$B$,$J$/$F$b7Y9p$9$ke(B
> - e$B%a%C%;!\<%8$re(Bobsoletee$B$+$ie(Bignorede$B$KJQ99$9$ke(B
> 
> e$B$H$$$&BP1~$K$7$h$&$H;W$$$^$9!#e(B

e$BBEEv$G$O$J$$$G$7$g$&$+!#e(B

ruby -Kn -e ‘p “\xF0\x80\x80\xBC”.match(Regexp.new(".", nil, “u”))’  
#\<MatchData “\xF0”\>

e$B$"$?$j$O;v\>p$rCN$i$J$$$H$S$C$/$j$7$^$9!#7Y9p$/$i$$$O=P$F$b$$$$$H;W$$$^$9!#e(B

> e$BJL$N0F$H$7$F$O!"e(B
> 
> - 'u’e$BBP1~$rI|3h$5$;$ke(B
> 
> e$B$H$$$&$b$N$b$"$j$($^$9$,!#e(B

ue$B$H$+e(Bee$B$O$H$b$+$/e(Bne$B$,M\_$7$$$3$H$O$"$k$s$8$c$J$$$G$9$+$M$(!#e(B

---

<div class="post-metadata">

**Author:** ![Shyouhei\_U](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/94ad74/32.png) [@Shyouhei\_U](https://www.ruby-forum.com/u/Shyouhei_U)\
**Post date:** [October 17, 2008, 1:32pm UTC](https://www.ruby-forum.com/t/bug-651-regexp-new-returns-strange-regexp-object/151006/6 "2008-10-17T13:32:07Z")

</div>

e$B$^$D$b$He(B e$B$f$-$R$m$G$9e(B

In message “Re: [ruby-dev:36761] Re: [Bug #651] Regexp.new returns  
strange regexp object”  
on Fri, 17 Oct 2008 11:44:01 +0900, Urabe S.  
[removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) writes:

|e$B$=$&$G$9$+e(B?  
|  
|% ruby1.9 -ve ‘p( //n == Regexp.new(“”, nil, “n”) )’  
|ruby 1.9.0 (2008-10-17 revision 17576) [x86\_64-linux]  
|false  
|  
|# e$BJL$NLdBje(B?

e$BJL$NLdBj$G$7$?!#e(B//ne$B$,e(Bfixede$B$G$J$+$C$?$H$$$&!#e(B

---

<div class="post-metadata">

**Author:** ![Shyouhei\_U](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/94ad74/32.png) [@Shyouhei\_U](https://www.ruby-forum.com/u/Shyouhei_U)\
**Post date:** [October 17, 2008, 4:45am UTC](https://www.ruby-forum.com/t/bug-651-regexp-new-returns-strange-regexp-object/151006/7 "2008-10-17T04:45:07Z")

</div>

e$BKNIt$G$9!#e(B

Yukihiro M. e$B$5$s$O=q$-$^$7$?e(B:

> |\> \* 'u’e$BBP1~$rI|3h$5$;$ke(B  
> |\>  
> |\> e$B$H$$$&$b$N$b$"$j$($^$9$,!#e(B  
> |\>  
> |ue$B$H$+e(Bee$B$O$H$b$+$/e(Bne$B$,M\_$7$$$3$H$O$"$k$s$8$c$J$$$G$9$+$M$(!#e(B
> 
> e$B$"!“e(Bne$B$O$”$$$+$o$i$:M-8z$G$9!#L5;k$5$l$k$h$&$K$J$C$?$N$Oe(Bne$B0J30e(B  
> e$B$Ne(Bee$B$H$+e(Bse$B$H$+e(Bue$B$H$+$G$9!#e(B

e$B$=$&$G$9$+e(B?

% ruby1.9 -ve ‘p( //n == Regexp.new("", nil, “n”) )’  
ruby 1.9.0 (2008-10-17 revision 17576) [x86\_64-linux]  
false

# e$BJL$NLdBje(B?