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CMD_IGNORE_RETURN is propagated into function invocations

From: Karsten Sperling
Subject: CMD_IGNORE_RETURN is propagated into function invocations
Date: Mon, 12 Nov 2007 17:03:34 +1300
User-agent: Thunderbird (X11/20071023)

Configuration Information [Automatically generated, do not change]:
Machine: i486
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='i486'
-DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='i486-pc-linux-gnu'
-DCONF_VENDOR='pc' -DLOCALEDIR='/usr/share/locale' -DPACKAGE='bash'
-DSHELL -DHAVE_CONFIG_H   -I.  -I../bash -I../bash/include -I../bash/lib
  -g -O2 -Wall
uname output: Linux cargocult 2.6.20-16-generic #2 SMP Sun Sep 23
19:50:39 UTC 2007 i686 GNU/Linux
Machine Type: i486-pc-linux-gnu

Bash Version: 3.2
Patch Level: 13
Release Status: release

        Whether orr not ERR traps get invoked for failed simple commands
        inside a function depends on whether or not the error status is
        to be ignored for any function invocation in the call stack
        leading to the current function. This makes it practically
        impossible to reliably use ERR traps for error handling inside
        functions. This affects the -e option as well.

        The documentation isn't clear on what the behaviour should be --
        is every command inside a function considered to be "part of"
        all command lists that directly or indirectly invoke the
        function? This would mean that a function cannot rely on a
        failed simple command behaving in any particular way -- to write
        a function that can handle this robustly, every command
        would have to be suffixed with either || true or || return.

        Unfortunately the situation is not as easy for -e: If a simple
        command failure inside a function caused the entire shell to
        terminate, any attempt by the caller to catch failures of that
        function would be ignored. It seems the most desirable behaviour
        would be to have a mode where a failed simple command causes the
        current function to propagate the status of the failed command
        to the caller.

        bash -c 'set -E; trap "echo ERR" ERR; f() { false; }; g() { f; }
; g; echo -; g || true'

        Don't propagate CMD_IGNORE_RETURN into function invocations.

*** execute_cmd.c.orig  2007-11-12 15:10:54.000000000 +1300
--- execute_cmd.c       2007-11-12 15:55:52.000000000 +1300
*** 3192,3199 ****

    tc = (COMMAND *)copy_command (function_cell (var));
-   if (tc && (flags & CMD_IGNORE_RETURN))
-     tc->flags |= CMD_IGNORE_RETURN;

    if (subshell == 0)
--- 3192,3197 ----

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