[pacman-dev] type -p tests in makepkg

[Isaac Good]

On Mon, Nov 16, 2009 at 10:30:07AM +0000, Allan McRae wrote:
> Hi,
> 
> I would like some clarification on what the bug in bash is that
> prevents us using [[ style tests when testing if a function exists.
> We have this in the two patches that change all the tests in
> makepkg:
> 
> * if [ $(type ... preserved due to a bash bug with [[ and set -e and
> ERR traps
> 
> I also have a patch from Cedric that makes the build() function
> optional which uses [[ for the "type -p" test.
> 
> Here is an example script based on code Cedric provided:
> 
> --start--
> #!/bin/bash -e
> 
> set -E
> trap 'echo >&2 "DANGER: ERRORS ABOUND!"' ERR
> 
> build() {
>  echo "build"
> }
> 
> [[ $(! type -t build) = "function" ]] && echo "yes" || echo "no"
> [[ $(! type -t package) = "function" ]] && echo "yes" || echo "no"
> --end--
> 
> That outputs "yes" for the build function and "no" for the package
> function without an error trap being triggered. I know the "!" is a
> workaround to stop the error trap being triggered, but is there
> something wrong with that?
> 
> Allan
> 

While hacks are ugly, I guess there is nothing wrong with that. I'll submit a bug report and maybe this will all be moot...
Just to throw it out, what about this?
type -t package | grep -q 'function' && echo "yes" || echo "no"