This is an issue mostly in tests, but also in some production code, e.g. search handler hooks, history actions and so on. Code gets an Entity(Document) and calls getFingerprint without checking if the entity supports this.
- https://gerrit.wikimedia.org/r/287580
- https://gerrit.wikimedia.org/r/290461
- https://gerrit.wikimedia.org/r/290900
- https://gerrit.wikimedia.org/r/335463
- https://gerrit.wikimedia.org/r/335464
- https://gerrit.wikimedia.org/r/335614
- https://gerrit.wikimedia.org/r/335615
- https://gerrit.wikimedia.org/r/335617
- https://gerrit.wikimedia.org/r/337849
- https://gerrit.wikimedia.org/r/339912
- https://github.com/wmde/WikibaseDataModelServices/pull/171