Re: Completion with -W fails if words contain ':'

[Keith Thompson]

OK, that explains the problem, and I have a workaround.

(Background: I have a personal tool that uses "foo:bar" syntax for
some of its arguments. I've modified the tool to use "foo/bar
instead.)

Escaping the colons with backslashes doesn't seem to work:

$ echo $BASH_VERSION
5.2.32(1)-release
$ echo $COMP_WORDBREAKS
"'@><=;|&(:
$ say() { echo "$@" ; }
$ complete -r
$ complete -W "abc\:abc abc\:xyz" say
$ complete
complete -W 'abc\:abc abc\:xyz' say
$ say abc:abc:abc:abc:abc: # hitting TAB multiple times
abc:abc:abc:abc:abc:
$

On Mon, Dec 2, 2024 at 11:51 AM Chet Ramey <chet.ramey@case.edu> wrote:
>
> On 12/2/24 12:52 AM, Keith Thompson wrote:
>
> > Bash Version: 5.2
> > Patch Level: 32
> > Release Status: release
> >
> > Description:
> > If the wordlist given to `complete -W` includes words
> >      containing the ':' character, completion misbehaves.
> >
> >      The problem seems to occur if two or more words in the wordlist
> >      share a common prefix ending with ':'.  The problem does not
> >      occur with other characters; I've tried '/' and '_'.
>
> This is from the (obsolete) FAQ (doc/FAQ):
>
> E13) Why does filename completion misbehave if a colon appears in the 
> filename?
>
> Filename completion (and word completion in general) may appear to behave
> improperly if there is a colon in the word to be completed.
>
> The colon is special to readline's word completion code:  it is one of the
> characters that breaks words for the completer.  Readline uses these 
> characters
> in sort of the same way that bash uses $IFS: they break or separate the words
> the completion code hands to the application-specific or default word
> completion functions.  The original intent was to make it easy to edit
> colon-separated lists (such as $PATH in bash) in various applications using
> readline for input.
>
> This is complicated by the fact that some versions of the popular
> `bash-completion' programmable completion package have problems with the
> default completion behavior in the presence of colons.
>
> The current set of completion word break characters is available in bash as
> the value of the COMP_WORDBREAKS variable.  Removing `:' from that value is
> enough to make the colon not special to completion:
>
> COMP_WORDBREAKS=${COMP_WORDBREAKS//:}
>
> You can also quote the colon with a backslash to achieve the same result
> temporarily.
>
> --
> ``The lyf so short, the craft so long to lerne.'' - Chaucer
>                  ``Ars longa, vita brevis'' - Hippocrates
> Chet Ramey, UTech, CWRU    chet@case.edu    http://tiswww.cwru.edu/~chet/