Bugzilla – Full Text Bug Listing
| Summary: | NonNull annotation not considered for enhanced for loops | ||
|---|---|---|---|
| Product: | [Eclipse Project] JDT | Reporter: | Sebastian Zarnekow <sebastian.zarnekow> |
| Component: | Core | Assignee: | Stephan Herrmann <stephan.herrmann> |
| Status: | VERIFIED FIXED | QA Contact: | |
| Severity: | normal | ||
| Priority: | P3 | CC: | srikanth_sankaran |
| Version: | 3.8 | ||
| Target Milestone: | 3.8 M6 | ||
| Hardware: | PC | ||
| OS: | Mac OS X - Carbon (unsup.) | ||
| Whiteboard: | |||
It would appear the right behavior is for this warning to not show up. But there should be a warning in the preceding line since there is no syntax to annotate a collection as containing only @NonNull elements and so as the cursor advances there is no non null guarantee that can be enforced by the null annotation processor. The other construct that allows a local to be declared works alright:
//--------------
import org.eclipse.jdt.annotation.NonNull;
public class X implements AutoCloseable {
@NonNull X[] x = null;
public static void main(String[] args) {
try (@NonNull X x = boo()) {
goo(x);
}
}
static X boo() {
return null;
}
static void goo(@NonNull X x) {
}
@Override
public void close() {
}
}
(In reply to comment #1) > It would appear the right behavior is for this warning to not show > up. But there should be a warning in the preceding line since there > is no syntax to annotate a collection as containing only @NonNull > elements and so as the cursor advances there is no non null guarantee > that can be enforced by the null annotation processor. I agree. Should be easy to fix for M6 Fixed for 3.8 M6 via commit d137239e9d64b43b4573cdfef965a2c47040a54e Normally, the annotation on the local variable declaration is analyzed as part of the initialization/assignment. The bug happened because in this particular case we have no AST representing an assignment to the local variable. As a side effect of fixing the bug, we now see another warning against "for(@NonNull String s: list)", where list is a 'List<String>': Potential type mismatch: required '@NonNull String' but nullness of the provided value is unknown. Until we have JSR 308 we cannot say 'List<@NonNull String>' so the elements have the legacy type String, which is not safely assignable to '@NonNull String'. Just mentioning so nobody is surprised about the new outcome. Verified for 3.8 M6 using Build id: I20120306-0800 |
import java.util.Collections; import java.util.List; import org.eclipse.jdt.annotation.NonNull; public class C { void loop() { List<String> list = Collections.emptyList(); for(@NonNull String s: list) { expectNonNull(s); } } void expectNonNull(@NonNull String s) {} } gives Potential type mismatch: required '@NonNull String' but nullness of the provided value is unknown on expectNonNull(s);