Remove duplicate -l option for init command

[ruslanys]

--list option should be displayed by default out-of-the-box. But InitCommand had 2 options with -l key: -l for --language and -l for --list. In that case, when OptionHelpFormatter.format(...) pushing options into TreeSet, the --list option disappears.

[pivotal-issuemaster]

@ruslanys Please sign the Contributor License Agreement!

Click here to manually synchronize the status of this Pull Request.

See the FAQ for frequently asked questions.

[pivotal-issuemaster]

@ruslanys Thank you for signing the Contributor License Agreement!

[ruslanys]

Fix #13940

[philwebb]

Very interesting that the duplicate causes it to just disappear. I wonder if we can force the app to fail hard when that happens?

[ruslanys]

@philwebb I agree this is strange behavior.
Unfortunately, in the CLI context, it's not clear when can we check options uniqueness.
In the current implementation, Spring Boot CLI is initializing command options when a command choose.
That means that we will be able to throw an exception only when user types spring init.

Moreover, for options recognizing Spring Boot CLI is using joptsimple library, especially OptionParser.

So, one of the ideas is to update the getParser() method and put validation under options() invocation.
Like:

private void checkOptionsUniqueness() {
	List<String> keys = parser.recognizedOptions().values().stream()
			.distinct()
			.flatMap(optionSpec -> optionSpec.options().stream())
			.collect(Collectors.toList());

	Set<String> hashSet = new HashSet<>();
	for (String key : keys) {
		if (!hashSet.add(key)) {
			throw new IllegalStateException("Option key [" + key + "] is duplicated.");
		}
	}
}

I can provide a separate PR for this.

[ruslanys]

Unfortunately, the example above won't fix all problems.
If somebody put several exactly the same keys, for instance, "list" for several options, then OptionsParser won't provide us with the actual list of options and parser.recognizedOptions() will return only one of the options.

[ruslanys]

The second approach is to validate option name and aliases at OptionHandler.option(...) method, but it will be possible to get parser directly and register option out of the OptionHandler class.

[ruslanys]

@philwebb Please take a look at #14466.

[snicoll]

Closed by 6e6c22c

[snicoll]

@ruslanys thank you very much for making your first contribution to Spring Boot.