fix: add HasHiddenParent() to skip hidden command subtrees in Walk()

[dearchap]

What type of PR is this?

• feature

What this PR does / why we need it:

When using Walk() to traverse the command tree, users who want to skip hidden commands currently check cmd.Hidden. However, the subcommands of a hidden command are not themselves hidden and still appear in the walk output. There is no way to check whether a command belongs to a hidden subtree without manually walking parent pointers, which are unexported.

This PR adds HasHiddenParent() bool to Command, which returns true if any ancestor has Hidden: true. Users can combine it with cmd.Hidden in their Walk callback to skip entire hidden subtrees:

cmd.Walk(func(c *cli.Command) error {
    if c.Hidden || c.HasHiddenParent() {
        return nil
    }
    // process visible commands only
})

Which issue(s) this PR fixes:

Fixes #2372

Testing

• go test ./... passes
• go vet ./... passes
• make v3diff shows only the new HasHiddenParent method
• make v3approve run to update API surface docs

Release Notes

Add Command.HasHiddenParent() method to help users skip subcommands of hidden commands during Walk().

[abitrolly]

Is it possible to add this to Walk examples?

[dearchap]

@abitrolly Added

[abitrolly]

If c.Hidden is set, then the function returns nil, the walk terminates, and c.HasHiddenParent is never reached, right?

[dearchap]

yeah

[abitrolly]

@dearchap so what's the point in having c.HasHiddenParent condition here? It could be that immediate parent is not hidden, but the grandfather is. Maybe c.AnyHiddenParent method would be better? If the logic is if any([c.Hidden for c in [c] + c.Parents]).

[dearchap]

See the implementation of HasHiddenParent. If any command in the chain has Hidden set it will return true

[abitrolly]

@dearchap I feel like the better API would be to add a generic way to check some property in current and all parent commands. Otherwise there has to be a plenty of method for each property.

And also, how to check that only the parent command has hidden status? If I want to hide intermediate command, but make all its children visible? This HasHiddenParent method seems too specific as for me.

[dearchap]

@abitrolly do you have a design in mind ?