GNU bug report logs - #10390
Bug with Test Command

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From: help-debbugs <at> gnu.org (GNU bug Tracking System)
To: Eric Blake <eblake <at> redhat.com>
Cc: tracker <at> debbugs.gnu.org
Subject: bug#10390: closed (Bug with Test Command)
Date: Wed, 28 Dec 2011 13:31:02 +0000

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Your message dated Wed, 28 Dec 2011 06:28:06 -0700
with message-id <4EFB1966.40702 <at> redhat.com>
and subject line Re: bug#10390: Bug with Test Command
has caused the debbugs.gnu.org bug report #10390,
regarding Bug with Test Command
to be marked as done.

(If you believe you have received this mail in error, please contact
help-debbugs <at> gnu.org.)


-- 
10390: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=10390
GNU Bug Tracking System
Contact help-debbugs <at> gnu.org with problems

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From: "Mathi.C" <mathiazhaganc <at> gmail.com>
To: bug-coreutils <at> gnu.org
Subject: Bug with Test Command
Date: Wed, 28 Dec 2011 00:12:49 -0600

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Hi,

I have come across a scenario where test command resulted wrong result than
expected.

Please follow the below steps to simulate the scenario.
1. Define a variable to blank/null
     export a=
2. Test the parameter with test command on file exists
     test -f $a
3. Echo the result of the last executed command
    echo $?

Result we get is "0" -success, whereas the test command (step 2) should
error with parameter expected after " test -f".

-- 
Regards,
Mathi.C

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From: Eric Blake <eblake <at> redhat.com>
To: "Mathi.C" <mathiazhaganc <at> gmail.com>
Cc: 10390-done <at> debbugs.gnu.org
Subject: Re: bug#10390: Bug with Test Command
Date: Wed, 28 Dec 2011 06:28:06 -0700

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tag 10390 notabug
thanks

On 12/27/2011 11:12 PM, Mathi.C wrote:
> Hi,
> 
> I have come across a scenario where test command resulted wrong result than
> expected.
> 
> Please follow the below steps to simulate the scenario.
> 1. Define a variable to blank/null
>      export a=
> 2. Test the parameter with test command on file exists
>      test -f $a

There's your problem.  You failed to properly quote things.  Per shell
expansion rules, unquoted $a is elided, rather than an empty argument,
which means you passed test exactly one argument ("-f"), and since that
one argument is not empty, it is always true.

If you want to cope with an explicit empty string, you must use quoting:

test -f "$a"

> 3. Echo the result of the last executed command
>     echo $?

As this behavior matches POSIX requirements on test, there is nothing to
fix here.  Also, be aware that you were probably testing your shell's
built-in test, rather than coreutils' test (running the latter usually
requires that you do things like 'env test' or '/usr/bin/test' to bypass
shell built-ins).

-- 
Eric Blake   eblake <at> redhat.com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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