pg_ctl failure with older Bourne shells (use ${1:+"$@"})

Yes, I have seen this fix before. Are people still using shells that
don't handle "$@" properly? I guess so or you wouldn't have reported
it.

We only use "$@" in a few places so I am applying this patch.

---------------------------------------------------------------------------

Mike Coleman wrote:

Your name : Mike Coleman
Your email address : mkc@mathdogs.com

System Configuration
---------------------
Architecture (example: Intel Pentium) :alpha

Operating System (example: Linux 2.0.26 ELF) :Tru64 5.1

PostgreSQL version (example: PostgreSQL-7.2.1): PostgreSQL-7.2.1

Compiler used (example: gcc 2.95.2) :gcc 3.1

Please enter a FULL description of your problem:
------------------------------------------------

The pg_ctl script uses the "$@" construct. Newer shells will replace
this with nothing if $@ is empty, but older shells will not. The
alternate form in the patch below will work for both new and old
shells.

Please describe a way to repeat the problem. Please try to provide a
concise reproducible example, if at all possible:
----------------------------------------------------------------------

The problem occurs with this command, for example:

$ /usr/local/pgsql/bin/pg_ctl -D /data1/postgres-0 -l logfile start

If you know how this problem might be fixed, list the solution below:
---------------------------------------------------------------------

--- /usr/local/pgsql/bin/pg_ctl.dist    2002-07-18 11:34:25.000000000 -0500
+++ /usr/local/pgsql/bin/pg_ctl 2002-07-18 14:44:35.000000000 -0500
@@ -332,12 +332,12 @@
fi

if [ -n "$logfile" ]; then
-        "$po_path" "$@" </dev/null >>$logfile 2>&1 &
+        "$po_path" ${1:+"$@"} </dev/null >>$logfile 2>&1 &
else
# when starting without log file, redirect stderr to stdout, so
# pg_ctl can be invoked with >$logfile and still have pg_ctl's
# stderr on the terminal.
-        "$po_path" "$@" </dev/null 2>&1 &
+        "$po_path" ${1:+"$@"} </dev/null 2>&1 &
fi

# if had an old lockfile, check to see if we were able to start

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-- 
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 853-3000
  +  If your life is a hard drive,     |  830 Blythe Avenue
  +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026

Bruce Momjian <pgman@candle.pha.pa.us> writes:

Yes, I have seen this fix before. Are people still using shells that
don't handle "$@" properly? I guess so or you wouldn't have reported
it.

I remember having submitted just such a patch a few years ago (for a
different one of our scripts of course) when I was still using HPUX 9.
I'm not sure if later HPUXen have better shells. Plain /bin/sh on this
platform is ancient.

We only use "$@" in a few places so I am applying this patch.

Could you check for other scripts where the same thing may have snuck
in?

BTW, O'Reilly's "Unix Power Tools" recommends
${1+"$@"}
as the most portable replacement for "$@". Mike's version has :+
which is not the same. My man page for the Bourne shell says

${parameter:+word}
If parameter is set and is non-null, substitute word;
otherwise substitute nothing.

...

If the colon (:) is omitted from the above expressions, the shell only
checks whether parameter is set or not.

It looks to me like the book's method is more correct --- it won't mess
up in the case where $1 has been explicitly given as "".

regards, tom lane

Blah. Yeah, I muffed that--don't use a colon.

Regarding Bruce's comment, you wouldn't think they're still around, but this is what /bin/sh does on Tru64 5.1. (5.1 is almost the latest version; there's a 5.1a.)

Mike

Tom Lane wrote:

We only use "$@" in a few places so I am applying this patch.

Could you check for other scripts where the same thing may have snuck
in?

Yes, I checked, and I saw pgaccess using it too. I sent them a patch.

BTW, O'Reilly's "Unix Power Tools" recommends
${1+"$@"}
as the most portable replacement for "$@". Mike's version has :+
which is not the same. My man page for the Bourne shell says

Changed.

-- 
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 853-3000
  +  If your life is a hard drive,     |  830 Blythe Avenue
  +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026