Debian Bug report logs - #86397
[commented upstream] `case' inside of `$( )' command substitution gives syntax error

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Message #5 received at submit@bugs.debian.org (full text, mbox, reply):

From: Jeff Sheinberg <jeffsh@erols.com>

To: submit@bugs.debian.org

Subject: bash: `case' inside of `$( )' command substitution gives syntax error

Date: Sat, 17 Feb 2001 14:56:14 -0500 (EST)

Package: bash
Version: 2.04-9
Severity: normal

Hi,

The following typescript shows that bash reports a syntax error
for a `case' statement inside of the `$( )' form of command
substitution.  I looked at the SUSv2 docs, and according to my
reading, this should be a legal shell construct.

Both ash and ksh93 handle this correctly, while bash and pdksh do
not.  Also note that the same `case' inside of either the old
style (back-quoted) command substitution or inside of a sub-shell
`( )' _is_ handled correctly by bash.

Note too that if the case selector has the leading (optional) `(',
then bash will handle the otherwise same `case' correctly.

Here are some notes regarding the typescript,

    1. !137 - bash gives syntax error, new style $( ).
    2. !138 - ok with (2) case selector, new style $( ).
    3. !139 - ok with  2) case selector, old style ` `.
    4. !140 - ok with  2) case selector, sub-shell ( ).
    5. !141 - ok with (2) case selector, sub-shell ( ).

Here is the typescript itself,

    137 jeff ~ $ do_shells 'aa=$( case 1 in 2) ;; esac )'
    ========================================================================
    >> aa=$( case 1 in 2) ;; esac ) <<
    sh: line 1: syntax error near unexpected token `;'
    sh: line 1: `aa=$( case 1 in 2) ;; esac )'
    -- sh -- exit status 2
    -- ash --
    bash: line 1: syntax error near unexpected token `;'
    bash: line 1: `aa=$( case 1 in 2) ;; esac )'
    -- bash -- exit status 2
    pdksh: <stdin>[1]: syntax error: `;;' unexpected
    -- pdksh -- exit status 1
    -- ksh93 --

    138 jeff ~ $ do_shells 'aa=$( case 1 in (2) ;; esac )'
    ========================================================================
    >> aa=$( case 1 in (2) ;; esac ) <<
    -- sh --
    -- ash --
    -- bash --
    -- pdksh --
    -- ksh93 --

    139 jeff ~ $ do_shells 'aa=` case 1 in 2) ;; esac `'
    ========================================================================
    >> aa=` case 1 in 2) ;; esac ` <<
    -- sh --
    -- ash --
    -- bash --
    -- pdksh --
    -- ksh93 --

    140 jeff ~ $ do_shells '( case 1 in 2) ;; esac )'
    ========================================================================
    >> ( case 1 in 2) ;; esac ) <<
    -- sh --
    -- ash --
    -- bash --
    -- pdksh --
    -- ksh93 --

    141 jeff ~ $ do_shells '( case 1 in (2) ;; esac )'
    ========================================================================
    >> ( case 1 in (2) ;; esac ) <<
    -- sh --
    -- ash --
    -- bash --
    -- pdksh --
    -- ksh93 --

Thanks,
-- 
Jeff Sheinberg  <jeffsh@erols.com>


-- System Information
Debian Release: woody/testing
Kernel Version: Linux eden-hda7.my.local 2.2.18 #2 Wed Feb 7 08:10:35 EST 2001 i586 unknown

Versions of the packages bash depends on:
ii  base-files     2.2.6          Debian base system miscellaneous files
ii  libc6          2.2.1-1        GNU C Library: Shared libraries and Timezone
ii  libncurses5    5.0-6.0potato1 Shared libraries for terminal handling
ii  libreadline4   4.1-4          GNU readline and history libraries, run-time

--- Begin /etc/bash.bashrc (modified conffile)
.  /etc/local/1.sh  "/etc/bash.bashrc"
shopt -s checkwinsize

--- End /etc/bash.bashrc

Message #10 received at 86397@bugs.debian.org (full text, mbox, reply):

From: Matthias Klose <doko@cs.tu-berlin.de>

To: Jeff Sheinberg <jeffsh@erols.com>, 86397@bugs.debian.org

Subject: Bug#86397: bash: `case' inside of `$( )' command substitution gives syntax error

Date: Sat, 3 Mar 2001 19:13:25 +0100 (MET)

Reply of upstream author:

From: Chet Ramey <chet@nike.ins.cwru.edu> 
 
This is a hard problem to fix.  I've looked at various ways to do so,
and 
it gets very messy when you've got a yacc-based parser. 
 
POSIX.2 noted this situation, and added an optional `(' before the 
case pattern, so the parens match.  Since most posix-like shells  
support it, that is the syntax I recommend. 

Message #31 received at 86397-done@bugs.debian.org (full text, mbox, reply):

From: Gioele Barabucci <gioele@svario.it>

To: 86397-done@bugs.debian.org

Subject: Re: Bug#86397: bash: `case' inside of `$( )' command substitution gives syntax error

Date: Mon, 15 Apr 2024 12:52:27 +0200

Version: 5.0-6

On Sat, 17 Feb 2001 14:56:14 -0500 (EST) Jeff Sheinberg 
<jeffsh@erols.com> wrote:
> The following typescript shows that bash reports a syntax error
> for a `case' statement inside of the `$( )' form of command
> substitution.  I looked at the SUSv2 docs, and according to my
> reading, this should be a legal shell construct.
> 
>     137 jeff ~ $ do_shells 'aa=$( case 1 in 2) ;; esac )'
>     ========================================================================
>     >> aa=$( case 1 in 2) ;; esac ) <<
>     sh: line 1: syntax error near unexpected token `;'
>     sh: line 1: `aa=$( case 1 in 2) ;; esac )'
>     -- sh -- exit status 2
>     -- ash --
>     bash: line 1: syntax error near unexpected token `;'
>     bash: line 1: `aa=$( case 1 in 2) ;; esac )'
>     -- bash -- exit status 2
>     pdksh: <stdin>[1]: syntax error: `;;' unexpected
>     -- pdksh -- exit status 1
>     -- ksh93 --

Hi,

this issue does not seem to affect version 5.0-6 and later of bash.

    $ aa=$( case 1 in 2) ;; esac )
    $ echo "$aa"

    $ aa=$( case 1 in 2) ;; *) echo "else" ;; esac )
    $ echo $aa
    else

Please reopen this bug if you can still reproduce this issue.

Regards,

-- 
Gioele Barabucci

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