[BusyBox 0006304]: expr returns exitcode of 0 for certain variants of '0' (mismatch with coreutils)

[bugs at busybox.net]

The following issue has been SUBMITTED. 
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http://busybox.net/bugs/view.php?id=6304 
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Reported By:                pgbovine
Assigned To:                BusyBox
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Project:                    BusyBox
Issue ID:                   6304
Category:                   Standards Compliance
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     assigned
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Date Submitted:             11-11-2008 14:01 PST
Last Modified:              11-11-2008 14:01 PST
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Summary:                    expr returns exitcode of 0 for certain variants of
'0' (mismatch with coreutils)
Description: 
>From 'info expr':

   Exit status:

     0 if the expression is neither null nor 0,
     1 if the expression is null or 0,

expr should return 1 if the expression is '0'.  coreutils thinks that
anything with a series of zeroes, even followed by leading dashes,
qualifies as '0' and thus returns 1 for all of these variants:

$ expr '0'
0
$ echo $?
1

$ expr '-0'
-0
$ echo $?
1

$ expr '00'
00
$ echo $?
1

$ expr '-00'
-00
$ echo $?
1

However, busybox only thinks that the literal '0' alone qualifies as 0:

$ ./busybox expr '0'
0
$ echo $?
1

and other variants don't qualify as '0', so it returns an exitcode of 0
rather than 1 (sorry if this is semi-confusing, but it's in the specs):

$ ./busybox expr '-0'
-0
$ echo $?
0

$ ./busybox expr '00'
00
$ echo $?
0

$ ./busybox expr '-00'
-00
$ echo $?
0

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Issue History 
Date Modified   Username       Field                    Change               
====================================================================== 
11-11-08 14:01  pgbovine       New Issue                                    
11-11-08 14:01  pgbovine       Status                   new => assigned     
11-11-08 14:01  pgbovine       Assigned To               => BusyBox         
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