The CLI silently fails when attempting to use an invalid command

[nihalgonsalves]

There is no response for invalid commands, nor any indication via the exit code:

$ ktlint -V
0.35.0

$ ktlint foo

$ echo $? 
0  

Expected Behaviour:

A typo or invalid command should generate an error message and return with a non-zero exit code.

[Tapchicoma]

In your example foo is file pattern ktlint uses to find *.kt files. If you will run with ./ktlint --foo then it will fail execution with Error: Unmatched argument [--foo] and general help.

Imho exit code 0 is valid in ./ktlint foo case as it means no Kotlin files found and everything is ok.

[nihalgonsalves]

@Tapchicoma Thanks for the explanation. However, I still believe that the exit code isn't valid, as top level commands (installGitPreCommitHook, installGitPrePushHook, printAST, applyToIDEA, applyToIDEAProject) exist. Misspelling one of these should not result in a successful exit.

I see why it isn't an easy fix. One option to inform users about a misspelling or invalid command could be to print a warning such as "no files matched" to stderr.