# \[Bug #2995\] TestHash#test\_recursive\_check fails

**URL:** <https://www.ruby-forum.com/t/bug-2995-testhash-test-recursive-check-fails/185607>\
**Category:** Development\
**Created:** [March 23, 2010, 11:15am UTC](https://www.ruby-forum.com/t/bug-2995-testhash-test-recursive-check-fails/185607 "2010-03-23T11:15:36Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![Shugo\_M](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/7ea924/32.png) [@Shugo\_M](https://www.ruby-forum.com/u/Shugo_M)\
**Post date:** [March 23, 2010, 11:15am UTC](https://www.ruby-forum.com/t/bug-2995-testhash-test-recursive-check-fails/185607/1 "2010-03-23T11:15:36Z")

</div>

Bug #2995: TestHash#test\_recursive\_check fails  
[http://redmine.ruby-lang.org/issues/show/2995](http://redmine.ruby-lang.org/issues/show/2995)

e$B5/I\<\<Te(B: Shugo M.  
e$B%9%F!\<%?%9e(B: Open, e$BM%@hEYe(B: Normal  
e$BC4Ev\<Te(B: Nobuyoshi N., e$B%+%F%4%je(B: core, Target version:  
1.9.2  
ruby -v: ruby 1.9.2dev (2010-03-23 trunk 27020) [i686-linux]

e$BA0ED$G$9!#e(B

e$B0J2\<$NJQ99e(B(r26961)e$B$G!“e(BTestHash#test\_recursive\_checke$B$,\<:GT$9$k$h$&$K$J$C$F$$$ke(B  
e$B$N$G$9$,!”$3$NJQ99$O0U?^E\*$G$7$g$&$+!#e(B

Wed Mar 17 16:25:53 2010 Nobuyoshi N. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)

```
    * hash.c (rb_hash_aset): allow recursive key. [ruby-core:24648]

```

[ruby-core:24648]e$B$r8+$k$H!"e(B

> > h={}  
> > =\> {}  
> > h[:key] = h  
> > =\> {:key=\>{…}}  
> > h.hash  
> > ArgumentError: recursive key for hash

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h[h] = :foo

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e$B$^$?!“e(Btest\_recursive\_checke$B$K$”$k$h$&$Ke(B

h = {}  
h[h] = :foo

e$B$N$h$&$J%3!\<%I$r\<B9T$7$F$b!"e(Bh[h]e$B$Ge(B:fooe$B$O\<hF@$G$-$^$;$s!#e(B  
r26961e$B$O$I$&$$$&0U?^$NJQ99$J$N$G$7$g$&$+!#e(B

---

<div class="post-metadata">

**Author:** ![Shugo\_M](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/7ea924/32.png) [@Shugo\_M](https://www.ruby-forum.com/u/Shugo_M)\
**Post date:** [March 24, 2010, 9:09am UTC](https://www.ruby-forum.com/t/bug-2995-testhash-test-recursive-check-fails/185607/2 "2010-03-24T09:09:02Z")

</div>

e$B$J$+$@$G$9!#e(B

At Tue, 23 Mar 2010 19:15:10 +0900,  
Shugo M. wrote in [ruby-dev:40735]:

> e$B0J2\<$NJQ99e(B(r26961)e$B$G!“e(BTestHash#test\_recursive\_checke$B$,\<:GT$9$k$h$&$K$J$C$F$$$ke(B  
> e$B$N$G$9$,!”$3$NJQ99$O0U?^E\*$G$7$g$&$+!#e(B

e$B0l1~0U?^E\*$G$9$,!"8!F$ITB-$G$7$?!#e(B

> e$B$^$?!“e(Btest\_recursive\_checke$B$K$”$k$h$&$Ke(B
> 
> h = {}  
> h[h] = :foo
> 
> e$B$N$h$&$J%3!\<%I$r\<B9T$7$F$b!"e(Bh[h]e$B$Ge(B:fooe$B$O\<hF@$G$-$^$;$s!#e(B

rehashe$B$9$l$P\<hF@$G$-$k$h$&$G$9$,!“%-!\<$G:F5”$9$ke(BHashe$B$Oe(Breplacee$B$de(B  
updatee$B$G$b:n$l$k$N$G!"%(%i!\<$K$9$k$J$i0J2\<$N$h$&$K$9$k$Y$-$G$7$ge(B  
e$B$&$+!#e(B

> r26961e$B$O$I$&$$$&0U?^$NJQ99$J$N$G$7$g$&$+!#e(B

[http://twitter.com/lchin/status/10610389214](http://twitter.com/lchin/status/10610389214)  
[http://twitter.com/lchin/status/10610640493](http://twitter.com/lchin/status/10610640493)  
e$B$"$?$j$G$9!#e(Br24943e$B$G$NJQ99O3$l$+$H;W$C$?$N$G$9$,!#e(B

diff --git i/hash.c w/hash.c  
index 0b863bd…0e4e3dc 100644  
— i/hash.c  
+++ w/hash.c  
@@ -276,4 +276,7 @@ hash\_update(VALUE hash, VALUE key)  
rb\_raise(rb\_eRuntimeError, “can’t add a new key into hash during  
iteration”);  
}

- if (hash == key) {
- rb\_raise(rb\_eArgError, “recursive key for hash”);
- }  
}

---

<div class="post-metadata">

**Author:** ![Shugo\_M](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/7ea924/32.png) [@Shugo\_M](https://www.ruby-forum.com/u/Shugo_M)\
**Post date:** [March 25, 2010, 4:18am UTC](https://www.ruby-forum.com/t/bug-2995-testhash-test-recursive-check-fails/185607/3 "2010-03-25T04:18:05Z")

</div>

e$BA0ED$G$9!#e(B

2010e$BG/e(B3e$B7ne(B24e$BF|e(B17:08 Nobuyoshi N.  
[removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid):

> > e$B$N$h$&$J%3!\<%I$r\<B9T$7$F$b!"e(Bh[h]e$B$Ge(B:fooe$B$O\<hF@$G$-$^$;$s!#e(B
> 
> rehashe$B$9$l$P\<hF@$G$-$k$h$&$G$9$,!“%-!\<$G:F5”$9$ke(BHashe$B$Oe(Breplacee$B$de(B  
> updatee$B$G$b:n$l$k$N$G!"%(%i!\<$K$9$k$J$i0J2\<$N$h$&$K$9$k$Y$-$G$7$ge(B  
> e$B$&$+!#e(B

e$B$J$k$[$I!"e(B[]=e$B$NCf$Ge(Bselfe$B$H%-!\<$,F1$8%\*%V%8%'%/%H$@$C$?;~$O!"e(B[]=e$B$NFbIt$Ge(B  
rehashe$B$9$k$H$$$$$s$G$9$+$M!#e(B

> > r26961e$B$O$I$&$$$&0U?^$NJQ99$J$N$G$7$g$&$+!#e(B
> 
> [http://twitter.com/lchin/status/10610389214](http://twitter.com/lchin/status/10610389214)  
> [http://twitter.com/lchin/status/10610640493](http://twitter.com/lchin/status/10610640493)  
> e$B$"$?$j$G$9!#e(Br24943e$B$G$NJQ99O3$l$+$H;W$C$?$N$G$9$,!#e(B

Hashe$B$N%-!\<$K$9$k$H4m$J$$$b$N$OB\>$K$b$“$k$N$G!”$3$N%1!\<%9$@$1%(%i!\<$Ke(B  
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---

<div class="post-metadata">

**Author:** ![Shugo\_M](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/7ea924/32.png) [@Shugo\_M](https://www.ruby-forum.com/u/Shugo_M)\
**Post date:** [March 26, 2010, 11:39am UTC](https://www.ruby-forum.com/t/bug-2995-testhash-test-recursive-check-fails/185607/4 "2010-03-26T11:39:58Z")

</div>

e$BA0ED$G$9!#e(B

2010e$BG/e(B3e$B7ne(B25e$BF|e(B12:17 Shugo M. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid):

> Hashe$B$N%-!\<$K$9$k$H4m$J$$$b$N$OB\>$K$b$“$k$N$G!”$3$N%1!\<%9$@$1%(%i!\<$Ke(B  
> e$B$9$kI,MW$b$J$$$+$J$H;W$$$^$9!#e(B  
> 1.8e$B$H$N8\_49@-$H$$$&0UL#$G$b%(%i!\<$K$7$J$$J}$,$$$$$+$b$7$l$J$$$G$9$M!#e(B
> 
> e$B$H$/$K0[O@$,$J$1$l$P!"%F%9%H$NJ}$r=$@5$9$k$H$$$&$3$H$G$I$&$G$7$g$&$+!#e(B

e$B$H$j$"$($:%F%9%H$NJ}$r=$@5$7$F$\*$-$^$7$?!#e(B

---

<div class="post-metadata">

**Author:** ![Shugo\_M](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/7ea924/32.png) [@Shugo\_M](https://www.ruby-forum.com/u/Shugo_M)\
**Post date:** [March 26, 2010, 11:42am UTC](https://www.ruby-forum.com/t/bug-2995-testhash-test-recursive-check-fails/185607/5 "2010-03-26T11:42:54Z")

</div>

e$B%A%1%C%He(B #2995 e$B$,99?7$5$l$^$7$?!#e(B (by Shugo 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

This issue was solved with changeset r27062.  
Shugo, thank you for reporting this issue.  
Your contribution to Ruby is greatly appreciated.  
May Ruby be with you.

* * *

[http://redmine.ruby-lang.org/issues/show/2995](http://redmine.ruby-lang.org/issues/show/2995)