bash-completion not working properly with directories with spaces in them when using some commands

Good evening!

Unfortunately, I need to report an issue with Ununtu 20.04's bash-completion (bash_completion version 2.10). It can't properly expand directories with spaces when there are multiple options when using some commands. Here is an example:

$ mkdir -p "p00p/p00p 1"
$ mkdir -p "p00p/p00p 2"
$ ls -d p00p/p00p\ 1 p00p/p00p\ 2
'p00p/p00p 1' 'p00p/p00p 2'
$ ls p00p/p0<tab><tab>
p00p 1/ p00p 2/
$ ls p00p/p0<tab>1<tab> # <-- works: yields the expanded command: ls p00p/p00p\ 1/
$ wine p00p/p0<tab><tab> # <-- does NOT work: fails to show possible expansions: p00p 1/ p00p 2/
$ wine p00p/p0<tab>1<tab> # <-- does NOT work: fails to expand to: wine p00p/p00p\ 1/

I temporarily fixed it by patching the portion of bash_completion which invokes plusdirs with the version from my raspberry pi OS (bash_completion version 2.8). Here's the patch that fixes it:

--- /usr/share/bash-completion/bash_completion 2020-09-04 20:39:18.453560935 -0700
+++ /home/xxx/bash_completion 2020-09-04 20:39:13.625394958 -0700
@@ -563,37 +559,28 @@
     _tilde "$cur" || return

     local -a toks
- local reset
+ local x reset

- if [[ "$1" == -d ]]; then
         reset=$(shopt -po noglob); set -o noglob
         toks=( $(compgen -d -- "$cur") )
- IFS=' '; $reset; IFS=$'\n'
- else
+ eval $reset
+
+ if [[ "$1" != -d ]]; then
         local quoted
         _quote_readline_by_ref "$cur" quoted

         # Munge xspec to contain uppercase version too
         # http://thread.gmane.org/gmane.comp.shells.bash.bugs/15294/focus=15306
- local xspec=${1:+"!*.@($1|${1^^})"} plusdirs=()
-
- # Use plusdirs to get dir completions if we have a xspec; if we don't,
- # there's no need, dirs come along with other completions. Don't use
- # plusdirs quite yet if fallback is in use though, in order to not ruin
- # the fallback condition with the "plus" dirs.
- local opts=( -f -X "$xspec" )
- [[ $xspec ]] && plusdirs=(-o plusdirs)
- [[ ${COMP_FILEDIR_FALLBACK-} ]] || opts+=( "${plusdirs[@]}" )
-
+ local xspec=${1:+"!*.@($1|${1^^})"}
         reset=$(shopt -po noglob); set -o noglob
- toks+=( $(compgen "${opts[@]}" -- $quoted) )
- IFS=' '; $reset; IFS=$'\n'
+ toks+=( $( compgen -f -X "$xspec" -- $quoted ) )
+ eval $reset

         # Try without filter if it failed to produce anything and configured to
         [[ -n ${COMP_FILEDIR_FALLBACK:-} && -n "$1" && ${#toks[@]} -lt 1 ]] && {
             reset=$(shopt -po noglob); set -o noglob
- toks+=( $(compgen -f "${plusdirs[@]}" -- $quoted) )
- IFS=' '; $reset; IFS=$'\n'
+ toks+=( $( compgen -f -- $quoted ) )
+ eval $reset
         }
     fi

<EOF>

Unfortunately, to apply the patch with patch -p0, I had to type in the name of the file to patch because the patch I saved was only a subset of the patch produced by "diff -u -w" and my diff-fu isn't good enough to know how to fix it. But, providing the name of the file to be patched when prompted (/usr/share/bash-completion/bash_completion) made it work and after I sourced the new file the issue was fixed.

Thus, this appears to be a regression of sorts but my bash programming skills aren't good enough to fix it myself while ensuring that any functionality provided by the portions that I replaced isn't lost.

Thank you!

Very sincerely,

Jason A. Pfeil

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: bash-completion 1:2.10-1ubuntu1 [modified: usr/share/bash-completion/bash_completion]
ProcVersionSignature: Ubuntu 5.4.0-45.49-generic 5.4.55
Uname: Linux 5.4.0-45-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.20.11-0ubuntu27.8
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: ubuntu:GNOME
Date: Fri Sep 4 20:50:10 2020
Dependencies:

EcryptfsInUse: Yes
InstallationDate: Installed on 2020-08-29 (7 days ago)
InstallationMedia: Ubuntu 20.04.1 LTS "Focal Fossa" - Release amd64 (20200731)
PackageArchitecture: all
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: bash-completion
UpgradeStatus: No upgrade log present (probably fresh install)