Extra output and errors during shell completion

[marckhouzam]

What steps did you take:
There is extra output in the shell completion choices and in some cases is even causes errors during shell completion.

What happened:

For bash, notice the error in this particular case (some other bash completions do work):

bash
bash-5.1$ source <(kapp completion bash)
bash-5.1$ kapp help <TAB>
bash: ShellCompDirectiveNoFileComp

Succeeded: syntax error in expression (error token is "Succeeded")

For zsh, notice the extra output at the end (:4, Succeeded, etc):

$ source <(kapp completion zsh)
$ compdef _kapp kapp
$ kapp <TAB>
app-change                                                     -- App change (garbage-collect, list)
app-group                                                      -- app-group will deploy/delete an application for each subdirectory within a
completion                                                     -- Output shell completion code for the specified shell (bash, zsh or fish)
config-map                                                     -- Config map (list)
delete                                                         -- Delete app
deploy                                                         -- Deploy app
deploy-config                                                  -- Show default deploy config
help                                                           -- Help about any command
inspect                                                        -- Inspect app
label                                                          -- Print specified app label
list                                                           -- List all apps in a namespace
logs                                                           -- Print app's Pod logs
rename                                                         -- Rename app
service-account                                                -- Service account (list)
tools                                                          -- Tools (diff, inspect, list-labels)
version                                                        -- Print client version
:4                                                             Succeeded
Completion ended with directive: ShellCompDirectiveNoFileComp

Also happens for fish shell.

What did you expect:

Shell completion to work as expected, without error or extra output.

Anything else you would like to add:

Shell completion uses the hidden __complete command provided by the Cobra project to obtain the shell completion choices.

1. kapp should not print Succeeded for that command
2. output printed to stderr by the __complete command should not be redirected by kapp to stdout (that is the problem for the string output Completion ended with directive: ShellCompDirectiveNoFileComp)

This command is added by Cobra when rootCmd.Execute() is called, which makes it a little trickier to adjust the behaviour for it.

Environment:

• kapp version (use kapp --version): 0.52.0
• OS (e.g. from /etc/os-release): MacOS
• Kubernetes version (use kubectl version): N/A

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[renuy]

Thanks for reporting this @marckhouzam. Checking it out.

[marckhouzam]

BTW, some projects explicitly check if processing with the __complete command and adapt their behaviour accordingly.

For example: https://github.com/kubernetes/kubernetes/blob/d581cc90adba6c84919738841fe3e07302d53e33/staging/src/k8s.io/kubectl/pkg/cmd/cmd.go#L131

[cppforlife]

@marckhouzam which version of kapp are you using? i believe latest of kapp should not have this problem.

[marckhouzam]

@marckhouzam which version of kapp are you using? i believe latest of kapp should not have this problem.

Version 0.52.0 as installed by brew.
I just tried on the develop branch and I see the problem.

Note that this similar but not the same problem as #447. The completion command had a similar problem and now we need to fix the __complete command.

[praveenrewar]

output printed to stderr by the __complete command should not be redirected by kapp to stdout (that is the problem for the string output Completion ended with directive: ShellCompDirectiveNoFileComp)

💯

[renuy]

Released as part of v0.53.0