fix: All user code input should be validated #199

[astubbs]

You should not be able to pass in invalid code and get obscure errors like "index out of range" exceptions. I found one place for this but the code should be audited for it everywhere. Better to run slower and have excellent errors.

fixes #199

[gastaldi]

Can you format the sources using the formatter in https://github.com/forge/core/blob/master/eclipse-code-formatter-profile.xml?

[astubbs]

ok done, and replaced all the times I saw it in this file

[gastaldi]

Can we have a test that verifies this is working as proposed?

Also it would be nice if you could squash all commits from this PR

[astubbs]

Interestingly, the source validator is failing all the code snippets from the test, if they don't have a trailing ;

List<Problem> problems = Roaster.validateSnippet(stub);

java.lang.IllegalArgumentException: 
Invalid method code. [Problem: 'Syntax error, insert ";" to complete ClassBodyDeclarations' at 1:57-57]
	at org.jboss.forge.roaster.model.impl.MethodImpl.getMethodSources(MethodImpl.java:144)
	at org.jboss.forge.roaster.model.impl.MethodImpl.<init>(MethodImpl.java:133)
	at org.jboss.forge.roaster.model.impl.AbstractJavaSourceMemberHolder.addMethod(AbstractJavaSourceMemberHolder.java:352)
	at org.jboss.forge.test.roaster.model.MethodSignatureTest.testMethodSignatureParams(MethodSignatureTest.java:38)

Previously the code was just calling JavaClassSource temp = (JavaClassSource) Roaster.parse(stub); without validation. Odd the validator requires trailing ';' 🤔 ...