Bugzilla – Full Text Bug Listing
| Summary: | JDT null analysis does not take into consideration checks made in parent scope of 'for' loops | ||
|---|---|---|---|
| Product: | [Eclipse Project] JDT | Reporter: | Matthew DOnofrio <artist> |
| Component: | Core | Assignee: | JDT-Core-Inbox <jdt-core-inbox> |
| Status: | CLOSED INVALID | QA Contact: | |
| Severity: | normal | ||
| Priority: | P3 | CC: | stephan.herrmann |
| Version: | 4.7 | ||
| Target Milestone: | --- | ||
| Hardware: | PC | ||
| OS: | Windows 10 | ||
| Whiteboard: | |||
(In reply to Matthew DOnofrio from comment #0) > This may affect other forms of loops as well but I only tried this one: > > @NonNullByDefault > public class A { > public A(@Nullable String message) { > // Checked for null here... > if (null == message) > message = "null"; > > // Asserted not null here... > assert(null != message); > > for (int i = 0; i < 1; ++i) { > // Must still assert within loop scope to silence warning > assert(null != message); > > message = message.toString(); > } > > } > } Try adding an external annotation to String.toString() (?!?) It's the effect of the last assignment that spoils the previous assertion. Or am I missing anything? BTW: it took me almost a second to figure out why you are making assertions concerning the null literal :) Ahh, you are correct. To illustrate:
@NonNullByDefault
public class A {
public A(@Nullable String message) {
// Checked for null here...
if (null == message)
message = "null";
// Asserted not null here...
assert(null != message);
someMethod(message); // NO warning here (OK!)
message = message.toString();
someMethod(message); // Warning here (OK!)
message = message.toString(); // Potential null access warning
message = message.toString(); // Potential null access warning
message = message.toString(); // Potential null access warning
}
public void someMethod(String message) {
System.out.println(message.toString());
}
}
Is it possible to add an external annotation to the JDK methods? Or am I forced to suppress these kind of null warnings?
@NonNullByDefault
public class A {
public A(String message) {
// Null type safety (type annotations): The expression of type 'String'
// needs unchecked conversion to conform to '@NonNull String'
message = message.toString();
}
}
(In reply to Matthew DOnofrio from comment #3) > Is it possible to add an external annotation to the JDK methods? Or am I > forced to suppress these kind of null warnings? http://help.eclipse.org/neon/topic/org.eclipse.jdt.doc.user/tasks/task-using_external_null_annotations.htm?cp=1_3_9_2 I read this, yes. I'm using the latest Oracle JDK 1.8.0_121 which does not appear to have these annotations. The instructions provide an answer on how to configure Eclipse for external annotations but does not explain where I can get them. Are they not available at this time? (In reply to Matthew DOnofrio from comment #5) > I read this, yes. I'm using the latest Oracle JDK 1.8.0_121 which does not > appear to have these annotations. It's called "external" because it's not contained :) > The instructions provide an answer on how to configure Eclipse for external > annotations but does not explain where I can get them. Are they not > available at this time? There is a group[1][2] discussing how to collect external annotations for others to use, but at the time being, only a few incomplete sets exist. But then there's a simple Ctrl-1 solution to just add those annotations you need in your application. [1] https://mattermost.eclipse.org/eclipse/channels/jdt-null-analysis [2] http://www.lastnpe.org/ |
This may affect other forms of loops as well but I only tried this one: @NonNullByDefault public class A { public A(@Nullable String message) { // Checked for null here... if (null == message) message = "null"; // Asserted not null here... assert(null != message); for (int i = 0; i < 1; ++i) { // Must still assert within loop scope to silence warning assert(null != message); message = message.toString(); } } }