Re: [Bug] Exiting shell from function called by trap handler always produces status 0

[Mikael Magnusson <mikachu@xxxxxxxxx>]

On 10/9/18, Peter Stephenson <p.stephenson@xxxxxxxxxxx> wrote:
> On Mon, 2018-10-08 at 14:02 +0100, Martijn Dekker wrote:
>> When a trap handler exits the shell using the 'exit' command within a
>> function, the shell's exit status is zero even if another exit status
>> was given as an argument to the 'exit' command.
>>
>> $ Src/zsh -c 'fn() { exit 13; }; trap "fn" EXIT'
>> $ echo $?
>> 0
>> (expected output: 13)
>
> diff --git a/Src/builtin.c b/Src/builtin.c
> index c5b319b..b81acdb 100644
> --- a/Src/builtin.c
> +++ b/Src/builtin.c
> @@ -5709,7 +5709,13 @@ int shell_exiting;
>  mod_export void
>  zexit(int val, int from_where)
>  {
> -    /* Don't do anything recursively:  see below */
> +    static int exit_val;
> +    /*
> +     * Don't do anything recursively:  see below.
> +     * Do, however, update exit status --- there's no nesting,
> +     * a later value always overrides an earlier.
> +     */
> +    exit_val = val;
>      if (shell_exiting == -1)
>  	return;
>
> @@ -5757,7 +5763,7 @@ zexit(int val, int from_where)
>  #endif
>  	}
>      }
> -    lastval = val;
> +    lastval = exit_val;
>      /*
>       * Now we are committed to exiting any previous state
>       * is irrelevant.  Ensure trap can run.
> @@ -5771,9 +5777,9 @@ zexit(int val, int from_where)
>         release_pgrp();
>      }
>      if (mypid != getpid())
> -	_exit(val);
> +	_exit(exit_val);
>      else
> -	exit(val);
> +	exit(exit_val);
>  }
>
>  /* . (dot), source */
> diff --git a/Test/C03traps.ztst b/Test/C03traps.ztst
> index dce263f..3b5d4c6 100644
> --- a/Test/C03traps.ztst
> +++ b/Test/C03traps.ztst
> @@ -863,6 +863,9 @@ F:Must be tested with a top-level script rather than
> source or function
>  >a
>  >b
>
> +  $ZTST_testdir/../Src/zsh -fc 'fn() { exit 13; }; trap fn EXIT; exit'
> +13:Explicit exit in exit trap overrides status
> +
>  %clean
>
>    rm -f TRAPEXIT

We might as well make this test
+  $ZTST_testdir/../Src/zsh -fc 'fn() { exit $?+7; }; trap fn EXIT; exit 6'
+13:Explicit exit in exit trap overrides status

-- 
Mikael Magnusson