Ugh, yes, this is something I was looking at as well. I was considering if we could set a default, then optionally override, but Cobra currently doesn't allow for a completion to be replaced once set;

In that case, if the flag has no completion, it returns here;

Which returns with ShellCompDirectiveNoFileComp

I think ideally Cobra would allow setting a custom default for flags, but perhaps a somewhat dirty, but functional one would be to do it ourselves, and set a default at the very end of functions that constructed a command, e.g. at;

flags.VisitAll(func(flag *pflag.Flag) {
	// Set a default completion function if none was set. We don't look
	// up if it does already have one set, because Cobra does this for
	// us, and returns an error (which we ignore for this reason).
	_ = cmd.RegisterFlagCompletionFunc(flag.Name, completion.NoComplete)
})

return cmd

I was a bit on the fence on using VisitAll, but it looks like there's many places where Cobra already does, so maybe not too bad, WDYT?

I could not find a way to set a default ShellCompDirective for silencing the numerouns flags with inapproptiate file completions.

IMHO this should be handled in Cobra. I'll open a feature request for this.

Your workaround looks very promising, I'll give it a try.

Heh; I was working on this one, when I discovered completion doesn't work for specifying --attach multiple times.

I started looking "why???" because it does work for some other flags we define multiple times, which is when I discovered the reason; Cobra has some "magic" values for flag "types"; if the flag-type ends with Slice or Array it considers that it can be used multiple times. If not, it considers that the flag can only be set once and it removes it from the suggestions;

In our case, some types use list as name, which isn't matched. I'm considering contributing a patch to Cobra to make it somewhat smarter;

• make the matching case-insensitive
• possibly add list to the magic strings

But also to have it match SliceValue, which is an interface defined by the pflag module used by Cobra for flags. I think it's an omission that it doesn't consider that interface;

Ah, now I understand.
I was also wondering why the events --filter completion only works once.

Mostly "note to self" - I think it's fine to disable completion for these for now.

• For dns-option we could at some point consider adding the list from https://man7.org/linux/man-pages/man5/resolv.conf.5.html
• For dns-search I wonder how much sense it would make to complete based on the current host's settings. That would not make sense for a remote daemon, but wondering if it's still useful for situations where the daemon runs locally.
• (same for dns)

Note to self; I need to lookup if there's other special ones we define (meta-, alt-, possibly others)