fix: OOB in JDTCommentBuilder

[Egor18]

I think that refactoring of JDTCommentBuilder in #2822 did not go so well :|
This PR is to fix IndexOutOfBoundsException during model build for the following code:

void bug3() {
    if (false) {} // some comment
    else if (false) {}
}

java.lang.IndexOutOfBoundsException: Index: 0

	at spoon.support.util.EmptyClearableList.get(EmptyClearableList.java:90)
	at spoon.support.util.ModelList.get(ModelList.java:55)
	at spoon.support.reflect.code.CtBlockImpl.getStatement(CtBlockImpl.java:78)
	at spoon.support.compiler.jdt.JDTCommentBuilder$1.visitCtIf(JDTCommentBuilder.java:378)
	at spoon.support.reflect.code.CtIfImpl.accept(CtIfImpl.java:45)
	at spoon.reflect.visitor.CtInheritanceScanner.scan(CtInheritanceScanner.java:184)
	at spoon.support.compiler.jdt.JDTCommentBuilder$1.scan(JDTCommentBuilder.java:233)
	at spoon.support.compiler.jdt.JDTCommentBuilder.insertCommentInAST(JDTCommentBuilder.java:437)
	at spoon.support.compiler.jdt.JDTCommentBuilder.buildComment(JDTCommentBuilder.java:147)

[monperrus]

LGTM. @pvojtechovsky do you merge?

[pvojtechovsky]

thenStatement isn't always CtBlock in this context.

[Egor18]

Ok, I see, but it's exactly the way the original code was written (I did not really want to change it):

SourcePosition thenPosition = e.getThenStatement().getPosition().isValidPosition() == false ? ((CtBlock) e.getThenStatement()).getStatement(0).getPosition() : e.getThenStatement().getPosition();
SourcePosition elsePosition = e.getElseStatement().getPosition().isValidPosition() == false ? ((CtBlock) e.getElseStatement()).getStatement(0).getPosition() : e.getElseStatement().getPosition();

Would you like me to add an additional check like thenStatement instanceof CtBlock?

[pvojtechovsky]

I see that it is same code like before. I suggest to write it correctly, when we are already touching it.

Would you like me to add an additional check like thenStatement instanceof CtBlock?

yes please

[pvojtechovsky]

Thank you @Egor18