microg/GmsCore · error · IllegalStateException

Task is not yet completed

Error message

Task is not yet completed

What it means

DuplicateTaskCompletionException.of(task) is a factory that builds the exception describing a Task that was completed more than once. It defensively throws IllegalStateException 'Task is not yet completed' when the passed Task is not complete, since a duplicate-completion report only makes sense for an already-completed Task.

Source

Thrown at play-services-tasks/src/main/java/com/google/android/gms/tasks/DuplicateTaskCompletionException.java:29

import org.microg.gms.common.PublicApi;

/**
 * An exception indicating that something attempted to set a result, exception, or cancellation on a {@link Task} that was already completed.
 */
@PublicApi
public class DuplicateTaskCompletionException extends IllegalStateException {

    private DuplicateTaskCompletionException(String s) {
        super(s);
    }

    /**
     * Creates a DuplicateTaskCompletionException from a {@link Task}.
     *
     * The {@link Task} must be complete.
     */
    public static DuplicateTaskCompletionException of(Task<?> task) {
        if (!task.isComplete()) throw new IllegalStateException("Task is not yet completed");
        return new DuplicateTaskCompletionException("Task is already completed");
    }
}

View on GitHub (pinned to 157c9d86ac)

Solutions

1. Only call of(task) after confirming task.isComplete() returns true
2. Check that you are passing the Task being completed, not a different pending Task
3. Restructure completion code to guard: if (!task.isComplete()) don't report duplicate completion

Example fix

// before
throw DuplicateTaskCompletionException.of(pendingTask); // throws IllegalStateException
// after
if (task.isComplete()) {
    throw DuplicateTaskCompletionException.of(task);
}

// guard before calling the factory
if (!task.isComplete()) {
    return; // not a duplicate completion; skip reporting
}

try {
    throw DuplicateTaskCompletionException.of(task);
} catch (IllegalStateException e) {
    // task was not actually complete; wrong Task passed
}

When it happens

Trigger: Invoking DuplicateTaskCompletionException.of(task) with a Task whose isComplete() returns false — i.e. calling it from code that tries to complete a Task but the Task instance passed in is actually still pending.

Common situations: Custom Task completion logic (e.g. TaskCompletionSource wrappers) that reports duplicate completion without first checking task.isComplete(); passing the wrong (pending) Task to the factory.

Understand the failure class

Background: "Invalid state transition" errors: "status must be X, actually Y", "already rejected/charging/uninstalled", "cannot ... while running" — what they mean when a library rejects your call — this error's family across 31 libraries.

Related errors

• Must not be invoked on main thread
• Task is not yet complete
• Only one extension per type may be added
• Cannot add twice the same OnSwitchChangeListener
• Cannot remove OnSwitchChangeListener

AI-assisted analysis of microg/GmsCore@157c9d86ac (2026-09-06). Data as JSON: /api/errors/885810e237974c26. Report an issue: GitHub.