Fix:(issue_2209) Add mutex flags to completion

[dearchap]

What type of PR is this?

(REQUIRED)

• bug

What this PR does / why we need it:

(REQUIRED)

Which issue(s) this PR fixes:

(REQUIRED)

Fixes #2209

Special notes for your reviewer:

(fill-in or delete this section)

Testing

(fill-in or delete this section)

go test -run=TestMutuallyExclusiveFlagsCompletion

Release Notes

(REQUIRED)

Add mutually exclusive flags to shell completion

[louisroyer]

Hi,
I see that when you provide the flag m1, m2 is wrongly suggested (they are mutually exclusive, so the only proposed flags should be l1, l2 and m1).

Could you add this test case as well, and adapt the code to make it pass?

[dearchap]

@louisroyer m1 and m2 are part of same group and are exclusive with only l2 . l1 is a global flag and will be valid in all cases.

[louisroyer]

m1 and m2 are part of same group and are exclusive with only l2 . l1 is a global flag and will be valid in all cases.

oh, sorry I only tested against the example program from #2209: last 2 commands were not giving expected result, and tried to transpose this to your test scenario that I wrongly read 😅

Here are the test cases I was thinking about:

[louisroyer]

Suggested change

	printFlagSuggestions(lastArg, cmd.appliedFlags, cmd.Root().Writer)
	printFlagSuggestions(lastArg, flagSuggestions(cmd, cmd.appliedFlags), cmd.Root().Writer)

And add the following:

func allMutuallyExclusiveFlags(cmd *Command) [][][]Flag {
	var flags [][][]Flag
	for pCmd := cmd; pCmd != nil; pCmd = pCmd.parent {
		for _, mxflags := range pCmd.MutuallyExclusiveFlags {
			flags = append(flags, mxflags.Flags)
		}
	}
	return flags
}

// excludedFlags lists flags that are excluded from flag suggestions because of mutual exclusivity.
func excludedFlags(cmd *Command) []Flag {
	mxflags := allMutuallyExclusiveFlags(cmd)
	var excluded []Flag
	for _, flagsSet := range mxflags {
		isExcluded := false
		var maybeExcluded []Flag
		for _, flags := range flagsSet {
			if isExcluded {
				excluded = append(excluded, flags...)
			} else {
				for _, flag := range flags {
					if flag.IsSet() {
						isExcluded = true
						excluded = append(excluded, maybeExcluded...)
						break
					}
				}
				maybeExcluded = append(maybeExcluded, flags...)
			}
		}
	}
	return excluded
}

func flagSuggestions(cmd *Command, flags []Flag) []Flag {
	excludedFlags := excludedFlags(cmd)
	var sug []Flag
	for _, flag := range flags {
		if !flag.IsSet() && !hasFlag(excludedFlags, flag) {
			sug = append(sug, flag)
		}
	}
	return sug
}

By testing manually, it works on the examples.