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From: Martijn Dekker <martijn@inlv.org>
To: zsh-workers@zsh.org
Subject: Bug: [ "(" = ")" ] is true
Date: Wed, 09 Dec 2015 16:34:34 +0100	[thread overview]
Message-ID: <56684A0A.8010404@inlv.org> (raw)

There is a string comparison bug with `[' and `test'; the result is true
if the first string starts with '(' and the second string starts with ')'.

$ [ "(" = ")" ] && echo oops || echo ok
oops
$ [ ")" = "(" ] && echo oops || echo ok
ok
$ [ "((" = "))" ] && echo oops || echo ok
oops
$ [ "((" = ")x" ] && echo oops || echo ok
oops
$ [ "(x" = ")" ] && echo oops || echo ok
oops
$ [ "x(" = ")" ] && echo oops || echo ok
ok
$ [ "(" = "x)" ] && echo oops || echo ok
ok

This appears to be a long-standing bug. I confirmed it in:

zsh 4.3.6
zsh 5.1.1
zsh 5.2

I also found that the bug does *not* exist in zsh 4.1.1.

Also, `[[' does not have this problem.

Credit to /u/tilkau on reddit for discovering this bug:
https://www.reddit.com/r/bash/comments/3w1hm4/how_to_compare_values_to_literal/cxsknzh

Thanks,

- Martijn


             reply	other threads:[~2015-12-09 15:43 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-12-09 15:34 Martijn Dekker [this message]
2015-12-09 15:58 ` Stephane Chazelas
2015-12-09 16:31   ` Martijn Dekker
2015-12-09 20:27     ` Bart Schaefer
2015-12-09 16:24 ` Peter Stephenson

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