Mangled completion with tilde and Bash option 'failglob'

[Maelan]

Completion of paths involving a tilde has become unusable since a recent system upgrade, presumably since Bash has been upgraded to version 5.0 (hence it might be related to issue #298, but symptoms differ). I identified that the issue only arises when Bash option failglob is set.

Configuration:

• architecture x86-64
• Linux 5.0.3-arch1-1-ARCH (Archlinux)
• Bash 5.0.2(1)-release (from Archlinux’ package)
• bash-completion 2.8.1 (from Archlinux’ package)

Steps to reproduce:

‹tab› represents pressing the tabulation key (for completion), ^C represents the Control+c shortcut (to abort the current command line).

# start with a clean environment and configuration:
$ env -i bash --norc --noprofile
$ ls -F ~
TEST/  more_dirs/  more_files.txt
# no bash-completion, 'failglob' off:
$ shopt -u failglob
$ cd ~/T‹tab›EST/^C
$ ls ~/T‹tab›EST/^C
# no bash-completion, 'failglob' on:
$ shopt -s failglob
$ cd ~/T‹tab›EST/^C
$ ls ~/T‹tab›EST/^C
# with bash-completion, 'failglob' off:
$ source /usr/share/bash-completion/bash_completion
$ shopt -u failglob
$ cd ~/T‹tab›EST/^C
$ ls ~/T‹tab›EST/^C
# with bash-completion, 'failglob' on:
$ shopt -s failglob
$ cd ~/T‹tab›EST/^C
$ ls ~/T‹tab›[bash: no match: \~/T
]EST/^C
$ \cd ~/T‹tab›[bash: no match: \~/T
]EST/^C

The expected completion always gets appended to the command line but, when failglob is on, an error message is also printed (hereinabove, shown between brackets for clarity):

bash: no match: \~/T

This is the error message printed by Bash when pathname expansion fails and failglob option is on. Note that the tilde is incorrectly escaped. This message is not appended to the command line, but it mangles the display.

This happens with many commands, including ls, mv, rm and any custom command, but not with cd. However \cd does trigger the error, even though there is no alias of that name.

[Maelan]

I noticed another, more serious issue with tilde. This time, this is triggered by the Bash option nullglob. I suspect these are two manifestations of the same underlying bug.

Configuration: same

Steps to reproduce:

‹tab›‹tab› is double-pressing the tabulation key, so as to display all completion candidates.

# start with a clean environment and configuration:
$ env -i bash --norc --noprofile
$ ls -F ~
dir_in_home/  file_in_home
$ ls -F .
dir_in_currentdir/  file_in_currentdir
# no bash-completion, 'nullglob' off:
$ shopt -u nullglob
$ ls ~/‹tab›‹tab›
dir_in_home/  file_in_home
# no bash-completion, 'nullglob' on:
$ shopt -s nullglob
$ ls ~/‹tab›‹tab›
dir_in_home/  file_in_home
# with bash-completion, 'nullglob' off:
$ source /usr/share/bash-completion/bash_completion
$ shopt -u nullglob
$ ls ~/‹tab›‹tab›
dir_in_home/  file_in_home
# with bash-completion, 'nullglob' on:
$ shopt -s nullglob
$ ls ~/‹tab›‹tab›
dir_in_currentdir/  dir_in_home/  file_in_currentdir

As can be seen, when option nullglob is on, the completion candidates for ~/ are completely wrong: they mix the contents of the home directory with the contents of the current directory, and they miss the regular files from the home directory (in other words, candidates are the files which match either ~/*/ or * — in regard to the semantics of nullglob, I might see how * comes up, but I have a hard time explaining this ~/*/ with a slash appended…).

Again this happens with ls and most commands, but not cd… but it happens with \cd (this last one even has files in suggestions, although only directories should be suggested for cd completion).

[scop]

I don't expect it to necessarily make a difference, but please try out with the current master branch from here, or 2.9 (it was released earlier today). I'll get to this soonish unless someone beats me to it. In the meantime, see Troubleshooting in README.md.

[dsifford]

Update your arch packages and try again @Maelan. 2.9 seems to have done the trick for my issue in #298.

[Maelan]

Looks like upgrading bash-completion to 2.9-1 (from Archlinux’ package) fixed both issues. Thanks!

Plus, oh my, my long-gone man completion came back to life. What a day!