Trying to complete the . builtin doesn't work

[TestingPlant]

Describe the bug

When trying to find completions for the . builtin command, the below messages appear:

bash_completion: /usr/share//bash-completion/completions/.: is a directory
bash_completion: /usr/share/bash-completion/completions/.: is a directory

These messages only appear when trying to find completions for . the first time.

To reproduce

1. Run bash
2. Type . , including the trailing space
3. Press tab

Expected behavior

Completions for the . builtin should appear

Versions (please complete the following information)

• Operating system name/distribution and version: Arch Linux
• bash version, echo "$BASH_VERSION": 5.1.16(1)-release
• bash-completion version, (IFS=.; echo "${BASH_COMPLETION_VERSINFO[*]}"): 2.11.0

Additional context

I'm using the bash-completion-git package from the AUR, which uses the latest code from the master branch. Using the normal bash-completion package which uses version 2.11 doesn't have this issue.

Debug trace

log.txt

[abbeyj]

I bisected this down to ca361be. Possibly there should be a special case for .? A similar problem also happens if trying to find completions for a command called .. so if a special case is added for . then one for .. would also be useful. Alternatively maybe just going back to silently ignoring directories would be preferable?

[akinomyoga]

See #776