Github user aledsage commented on a diff in the pull request:
https://github.com/apache/brooklyn-server/pull/480#discussion_r103446823
--- Diff:
core/src/main/java/org/apache/brooklyn/util/core/task/BasicExecutionContext.java
---
@@ -96,7 +98,50 @@ public ExecutionManager getExecutionManager() {
/** returns tasks started by this context (or tasks which have all the
tags on this object) */
@Override
public Set<Task<?>> getTasks() { return
executionManager.getTasksWithAllTags(tags); }
-
+
+ /** performs execution without spawning a new task thread, though it
does temporarily set a fake task for the purpose of getting context;
+ * currently supports suppliers or callables */
+ @SuppressWarnings("unchecked")
+ @Override
+ public <T> Maybe<T> getImmediately(Object callableOrSupplier) {
+ BasicTask<?> fakeTaskForContext;
+ if (callableOrSupplier instanceof BasicTask) {
+ fakeTaskForContext = (BasicTask<?>)callableOrSupplier;
--- End diff --
Under what code path do we get here? Looking at
`ValueResolver.getMaybeInternal(...)`, `allowImmediateExecution` will be false
if the object is a task (rather than a `TaskFactory` or `DeferredSupplier`).
For example, the test below fails (added to `ValueResolverTest`). It leaves
a single instance of the task executing.
```
public void testTaskGetImmediatelyDoesNotBlock() {
final AtomicInteger executingCount = new AtomicInteger();
final Task<String> task = new BasicTask<>(new Callable<String>() {
public String call() {
executingCount.incrementAndGet();
try {
Time.sleep(Duration.ONE_MINUTE);
return "myval";
} finally {
executingCount.decrementAndGet();
}
}});
for (int i = 0; i < 3; i++) {
Maybe<String> result =
Tasks.resolving(task).as(String.class).context(app).immediately(true).getMaybe();
Asserts.assertTrue(result.isAbsent(), "result="+result);
}
Asserts.assertFalse(task.isSubmitted());
// The call below default times out after 30s while the task above
is still running
// Expect the task to not be left running.
Asserts.succeedsEventually(new Runnable() {
public void run() {
Asserts.assertEquals(executingCount.get(), 0);
}
});
}
```
I'm not convinced that we want to support setting a config key with a value
of type `Task` (long term). But I guess that will require more work, to change
how `DependentConfiguration` is implemented. So we do need to support it
short-term :-(
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