zsh adds empty string to local parameter when += is used

[jamil bio <jamilbio20@xxxxxxxxx>]

Hello good people,

It seems there is a bug which I will describe below.

I checked with usenet comp.unix.shell people and they said that is strange behavior.

I am using Z-shell 5.8. The problem is when I add elements to an array with += inside a function, an empty element is generated. The empty element is added only if I set array $files as local.

The following is an example code.


#!/bin/zsh
#!/bin/bash

func()
{
    local REPLY  files

    #unset files
    for REPLY in file1 file2 file3
    do
        files+=( "$REPLY" )
        echo "${#files[@]} -- ${files[@]}"
    done
}

func


If I set $files to local but unset it before the loop, the empty element is not added. Running the script with zsh returns:


2 --  file1
3 --  file1 file2
4 --  file1 file2 file3


While if we run the code with bash:


1 -- file1
2 -- file1 file2
3 -- file1 file2 file3


I was actually using a while read loop to read filenames, but the problem also occurs when I use the for loop. 

So the workaround suggested is to set $files as local and then later define files=( ) which will prevent empty element being added somehow.

Thanks for all your efforts in making zsh so great!