On Fri, 13 Jan 2023 15:08:59 GMT, Archie L. Cobbs <d...@openjdk.org> wrote:
>>> I guess I was confused because, while subclasses are a particularly sneaky >>> case where uninitialized values can show up, the above leak seems >>> potentially dangerous as well... >> >> Yes - and this very question did come up in the discussions around this >> warning (see amber-dev). >> >> The decision was to go with drawing the "warning boundary" at the >> compilation unit. The reasoning is that (a) this aligns with the compiler's >> "knowledge boundary", i.e., we can know for sure from code inspection, and >> also (b) focuses the warning on the particularly pernicious aspect of these >> bugs, which is that they arise from the non-obvious interaction among two or >> more files - even when looking at any single one of those files, there >> doesn't seem to be any apparent problem. In other words, we decided "not to >> try to save any single source code from itself". >> >> But I think it's still an interesting question. Maybe experience will >> provide more guidance over time. > >> Something seems to be up with the lint description for this-escape - compare >> this: > > Oops, will fix - thanks. > The decision was to go with drawing the "warning boundary" at the compilation > unit. The reasoning is that (a) this aligns with the compiler's "knowledge > boundary", i.e., we can know for sure from code inspection, and also (b) > focuses the warning on the particularly pernicious aspect of these bugs, > which is that they arise from the non-obvious interaction among two or more > files Sorry for being picky - you mention this "compilation unit" boundary before, but this is not really the reason here. Note that in my example B constructor calls out to a static method that is "outside" the boundary. The reason as to why my example is not flagged is simply that "escaping" is defined as "escaping into a subclass method", not just "escaping from the constructor (into some other compilation unit)". ------------- PR: https://git.openjdk.org/jdk/pull/11874
