Fix error when trying to get class annotation #5699

[ventusfortis]

Replace unsafe head with headOption.orNull in CfgNodeMethods.method for annotations, so annotations not inside a method no longer throw NoSuchElementException, as described in #5699

[maltek]

Thank you for the contribution!

You deleted a new line there, could you please fix that?

[ml86]

method is not supposed to return null. This does not solve the underlying problem of the broke assumption in the code. Can you please provide test input to illustrate the problem?

[maltek]

@ml86 I agree that randomly returning null is not how one is supposed to write scala code. Unfortunately, we already have existing code in that file that does the same for the same DSL method. I don't want to put up a higher bar on a new contributor's code than the existing implementation. So I would accept this. We can always convert the .method DSL to a proper Option based API even after merging this.

[ml86]

@maltek No, just because there is already bad code in there, it does not mean that we will accept more. This kind of code will make our lifes hell in the future.

[maltek]

@ventusfortis we've had some discussions about this topic outside here. We're not going to merge this PR here, but we'll solve the problem you had in different ways:

• [semanticcpg] Add better exception for .method on annotations. #5762 adds a new .methodOption method that actually works for annotation nodes (for annotations that annotate a method). The regular .method still won't work for annotation nodes, but it will raise an exception that points to the working .methodOption.
• Replace .orNull call #5761 will remove all the existing null cases from .method

[ventusfortis]

Ok, I agree, now I see issue.
I wanted to propose another solution to this with having #5762 in mind, but now I'll look into #5761. Thanks for answering!