Picocli 3.3.0

The picocli community is pleased to announce picocli 3.3.0.

This release contains a bugfix for the JLine TAB completion support and improves the error messages for missing required parameters and unmatched arguments.

This is the thirty-fourth public release.
Picocli follows semantic versioning.

Table of Contents

• New and noteworthy
• Promoted features
• Fixed issues
• Deprecations
• Potential breaking changes

New and Noteworthy

UnmatchedArgumentException Improvements

The UnmatchedArgumentException class now has several methods that allow an application to offer suggestions for fixes to the end user.

For example:

class App {
    @Option(names = "--file") File[] files;
    @Option(names = "--find") String pattern;
    
    public static void main(String[] args) {
        App app = new App();
        try {
            new CommandLine(app).parse(args);
            // ...
            
        } catch (ParameterException ex) {
            System.err.println(ex.getMessage());
            if (!UnmatchedArgumentException.printSuggestions(ex, System.err)) { // new API
                ex.getCommandLine().usage(System.err, ansi);
            }
        }
    } 
}

If you run this class with an invalid option that is similar to an actual option, the UnmatchedArgumentException.printSuggestions method will show the actual options. For example:

<cmd> -fi

Prints this output:

Unknown option: -fi
Possible solutions: --file, --find

This is the behaviour for the CommandLine convenience methods run, call and parseWithHandlers.
Note that if possible fixes are found, the usage help message is not displayed.

Promoted Features

Promoted features are features that were incubating in previous versions of picocli but are now supported and subject to backwards compatibility.

No features have been promoted in this picocli release.

Fixed issues

• [#411] Bugfix: Completion candidates were only generated for the first option, not for subsequent options.
• [#409] Enhancement: Improve error message for missing required positional parameters. Thanks to Mārtiņš Kalvāns and Olle Lundberg.
• [#298] Enhancement: Add help for mistyped commands and options. Added new API to UnmatchedArgumentException. Thanks to Philippe Charles.

Deprecations

No features were deprecated in this release.

Potential breaking changes

The error message format has changed. This may impact client tests that expect a specific error message.