Complete custom "git-foo" commands from "git foo" commandlines

[krobelus]

Since #7075, git-foo.fish files are sourced when Git completions are loaded.
However, at least Cobra (CLI framework for Go) provides completions like

complete -c git-foo ...

This means that completions are only offered when typing "git-foo "
and not on "git foo ". Fix this by forwarding the completion requests.

This patch breaks git-foo.fish files that directly add competions to "git" using

complete -c git -n '__fish_git_using_command foo' ...

Since we forward to "git-foo" which has no custom completions, "git foo"
would get default file completions. I don't know if this pattern is used
already. Since #7075 is not released yet, it is probably not common.

cc @soraxas

TODOs:

• Changes to fish usage are reflected in user documentation/manpages.
• Tests have been added for regressions fixed
• User-visible changes noted in CHANGELOG.rst

[faho]

This seems like a good idea, particularly because it matches git's semantics - any command named "git-thing" is available as "git thing", but that means it can also be called as "git-thing". So a "git-thing.fish" should have complete -c git-thing!

[soraxas]

I too reckon this is a good addition to make custom git-foo completions available when TAB completing git foo.

About the

complete -c git -n '__fish_git_using_command foo' ...

pattern, they are used in projects such as

https://github.com/tj/git-extras/blob/96b95392ac35d3ff033403e399cb7cfb7e94750b/etc/git-extras.fish#L80

For those sort of patterns, I think the new patch would add a completion that forwards git foo to git-foo that doesn't work, but since we are still sourcing the original file (source $git_ext), the original completion commands should still work. (i.e. there will be one redundant completion command, but it shouldn't beak the existing functionality?)

[krobelus]

(i.e. there will be one redundant completion command, but it shouldn't beak the existing functionality?)

The redundant completion command would cause fish to use file completions on git-extras , since no completions are defined for git-extras. I'll guard against that by only doing this if complete git-extras is nonempty. Then both ways work.

[soraxas]

I see that make sense, it didn't occured to me that complete -C 'foo ' would provide the default filelist completions even if foo is not a valid command.

Are there any simple way to check for the existence of completion command other than a guard that looks like this?

complete | string match -qr -- '\s-c git-foo'

[faho]

Are there any simple way to check for the existence of completion command other than a guard that looks like this?

After loading, with #7321 it's

complete foo

(#7321 makes it so it filters by the command and the -c is optional)

[soraxas]

I see! I was just testing the changes on my local machine to notice those old syntax errors, thanks for the clarification