fix(position): PartialSourcePosition only support getCompilationUnit

[tdurieux]

No description provided.

[pvojtechovsky]

I fixed the code which asks for position and doesn't checks that there is partial source position only.

But I am not happy with that solution, so feel free to rollback it ... it would be nicer if there would be a better way how to detect whether position
A) is valid - SourcePositionImpl
B) not valid - either NoSourcePosition or PartialSourcePositionImpl

I can imagine several solutions:
S1) PartialSourcePositionImpl extends NoSourcePosition
S2) boolean SourcePosition#isValid() ... or any better name
S3) SourcePosition#getSourceStart returns -1 for invalid SourcePosition and >=0 for valid source position. Other methods of SourcePosition might behave same
S4) ?

@tdurieux @monperrus WDYT?

[spoon-bot]

API changes: 1 (Detected by Revapi)

Old API: fr.inria.gforge.spoon:spoon-core:jar:6.3.0-20180405.225214-41 / New API: fr.inria.gforge.spoon:spoon-core:jar:6.3.0-SNAPSHOT

	visibility reduced
Old	method ElementPrinterHelper#createListPrinter(boolean, String, boolean, boolean, String, boolean, boolean, String)
New	method ElementPrinterHelper#createListPrinter(boolean, String, boolean, boolean, String, boolean, boolean, String)
Breaking	binary: breaking

[tdurieux]

Thank you for the fix.

I think I prefer the solution S1 but I would prefer to throw an exception instead of -1 in NoSourcePosition.

[monperrus]

ready for merge?

[pvojtechovsky]

@monperrus please see problem and possible solutions above and give us your opinion please. Thanks ;-)

[pvojtechovsky]

1. I like the idea of throwing of exception, because it avoids bugs caused by using invalid value -1.

what about change of NoSourcePosition and to throw exception there too?

2. I would like to have an easy way how to detect that SourcePostion is correct.

S1) PartialSourcePositionImpl extends NoSourcePosition

validity detected by: position instanceof NoSourcePosition == false

• it is longer then S2
• client must know internal implementation class to detect that

S2) boolean SourcePosition#isValid() ... or any better name

validity detected by: position.isValid()

[pvojtechovsky]

This PR is a step in a good way. So it is ready for merge. We can do other thinkgs in another PRs.