Add Check Support for Java 21 Pattern Matching for Switch Syntax: CommentsIndentation

[mahfouz72]

child of #14961

I have read check documentation: https://checkstyle.org/checks/misc/commentsindentation.html#CommentsIndentation
I have downloaded the latest checkstyle from: https://checkstyle.org/cmdline.html#Download_and_Run
I have executed the cli and showed it below, as cli describes the problem better than 1,000 words

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PS D:\CS\test> cat src/Test.java                                                
record ColoredPoint(int p, int x, boolean c) { }
record Rectangle(ColoredPoint upperLeft, ColoredPoint lowerRight) { }

public class Test {
    void test(Object obj) {
        switch (obj) {
            case ColoredPoint(int a, int b, _)
                   // comment 1
                    when (a >= b) :
                 // comment 2
                {} break;
            case ColoredPoint(int a, int b, _) when (b > 100) // comment 3
                    :
                     /* violation
                     *
                     */
            {}
             // ok
            break;
            default : System.out.println("none"); // violation
        }
         switch (obj) {
            case ColoredPoint(int a, int b, _)
                   // comment 1
                    when (a >= b)
                            // comment 2
                    -> {}
            case ColoredPoint(int a, int b, _) when (b > 100) // comment 3
                    ->
                     /* comment 4
                     *
                     */
            {}
             // ok
            default -> System.out.println("none");
        };
    }
}
PS D:\CS\test> cat config.xml                                                   
<?xml version="1.0"?>
<!DOCTYPE module PUBLIC
        "-//Puppy Crawl//DTD Check Configuration 1.3//EN"
        "http://www.puppycrawl.com/dtds/configuration_1_3.dtd">
<module name="Checker">
    <property name="charset" value="UTF-8"/>
    <module name="TreeWalker">
        <module name="CommentsIndentation">
        </module>
    </module>
</module>
PS D:\CS\test> java  -jar checkstyle-10.17.0-all.jar -c config.xml src/Test.java
Starting audit...
[ERROR] D:\CS\test\src\Test.java:8:20: Comment has incorrect indentation level 19, expected is 20, indentation should be the same level as line 9. [CommentsIndentation]
[ERROR] D:\CS\test\src\Test.java:10:18: Comment has incorrect indentation level 17, expected is 16, indentation should be the same level as line 11. [CommentsIndentation]      
[ERROR] D:\CS\test\src\Test.java:14:22: Block comment has incorrect indentation level 21, expected is 12, indentation should be the same level as line 17. [CommentsIndentation]
[ERROR] D:\CS\test\src\Test.java:18:14: Comment has incorrect indentation level 13, expected is 12, indentation should be the same level as line 19. [CommentsIndentation]      
[ERROR] D:\CS\test\src\Test.java:24:20: Comment has incorrect indentation level 19, expected is 20, indentation should be the same level as line 25. [CommentsIndentation]      
[ERROR] D:\CS\test\src\Test.java:26:29: Comment has incorrect indentation level 28, expected is 20, indentation should be the same level as line 27. [CommentsIndentation]      
[ERROR] D:\CS\test\src\Test.java:30:22: Block comment has incorrect indentation level 21, expected is 12, indentation should be the same level as line 33. [CommentsIndentation]
[ERROR] D:\CS\test\src\Test.java:34:14: Comment has incorrect indentation level 13, expected is 12, 12, indentation should be the same level as line 33, 35. [CommentsIndentation]
Audit done.
Checkstyle ends with 8 errors.
PS D:\CS\test> 

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We are ok here. This is working as intended.

[nrmancuso]

Let's add this example as a new test case for this check, there is lots of weird stuff here that might prove useful during regression testing.

[rnveach]

When we add inputs, we should have bad and properly formatted examples.