custom bash completion with whitespace and paths - linux

Question

I can't figure out what I am doing wrong. I have my bash_completion file setup as such:
_bcd()
{
local cur=${COMP_WORDS[COMP_CWORD]}
COMPREPLY=( $(compgen -W "$(back_directory.pl --complete $cur)" -- $cur) )
}
complete -o filenames -o nospace -F _bcd bcd
back_directory.pl is a program that will return directories paths up the tree: back_directory.pl --complete Th produces: This\ test/
But:
22:50:24-Josh#Joshuas-MacBook-Air:~/Desktop/bcd/This test/more white/t$ bcd Th<TAB><TAB>
This test/
As shown above, it doesn't auto complete for directories with whitespace in them (but it shows the completion option).
It should look like this: bcd This\ test/
I thought -o filenames should add the backslashes to escape the whitespace. Thanks for any help :)

Answer 1

Your single call to compgen produces a single word (containing embdedded newlines), so you are only adding a single possible completion to COMPREPLY. Instead, you need to process the output of back_directory.pl one item at a time. Each item is tested as a possible match, and if compgen returns a non-empty string, add that to COMPREPLY.
_bcd() {
local cur=${COMP_WORDS[COMP_CWORD]}
IFS=: read -a matches < <(back_directory.pl --complete "$cur")
for match in "${matches[#]}"; do
possible=$(IFS= compgen -W "$match" -- "$cur")
[[ $possible ] && COMPREPLY+=( "$possible" )
done
}
(Note: I'm assuming back_directory.pl will produce a single line of output similar to
directory1:directory two:directory three:directory4
)

Answer 2

For the sake of completion, this is the final file:
_bcd()
{
local cur=${COMP_WORDS[COMP_CWORD]}
IFS=: read -a matches < <(back_directory.pl --complete "$cur")
for match in "${matches[#]}"; do
possible=$(IFS= compgen -W "$match" -- "${cur#/}")
[[ $possible ]] && COMPREPLY+=( "$possible" )
done
longest=""
for e in "${COMPREPLY[#]}"; do
if [[ "$longest" == "" ]]; then
longest="$e"
fi
while [[ ! "$e" =~ ^$longest ]]; do
longest=${longest%?}
done
done
if [[ $longest != "$input" && "$cur" =~ ^/ ]]; then
for ((i=0; i<${#COMPREPLY[#]}; i++))
do
COMPREPLY[$i]="/${COMPREPLY[$i]}"
done
fi
}
complete -o filenames -o nospace -F _bcd bcd
The script back_directory.pl --complete will return a single line of paths delimited by colons.
My solution seems to be pretty terrible but it works.
Basically it removes a beginning slash from the current word, creates all the matches (containing no beginning slash) and then checks to see whether $longest is different from $input, which would mean bash would change your current word to something different--in which case we add back a beginning slash.