[setzer22]

What should they do? Static analysis would be nice, but it's probably too complex to adopt in that kind of codebase.

In the end, the only viable option is to forbid this behaviour, and document a rationale so nobody will enable it back again.

Perhaps they could make this warning bigger, but other than that...

[jefftk]

They could have added a regression test, no? Give it an example with ?attach= and verify that no attachment is added.