karatelabs/karate · error · DriverException

waitUntil (supplier) timeout

Error message

waitUntil (supplier) timeout

What it means

W3cDriver.waitUntil(Supplier) polls condition.get() every retry interval until the result is truthy or the timeout elapses, then throws a DriverException with the fixed message 'waitUntil (supplier) timeout'. This is the Java-embedded variant used from Java tests/custom code rather than a page JS expression.

Solutions

1. Log the supplier's return value each iteration to see why it never becomes truthy
2. Increase the timeout via waitUntil(condition, timeout)
3. Fix the supplier predicate so it correctly detects the target state
4. Ensure whatever the supplier waits on (async job, network event) is actually triggered

Example fix

// before
driver.waitUntil(() -> driver.getUrl().contains("/done")); // nav never happens
// after
driver.click("#finish"); // trigger the navigation first
driver.waitUntil(() -> driver.getUrl().contains("/done"), 30000);

// call condition.get() once yourself and inspect the result before polling
Object probe = condition.get();

try {
    Object result = driver.waitUntil(condition, timeout);
} catch (DriverException e) {
    // log condition.get() result to see why it never turned truthy
}

When it happens

Trigger: Calling driver.waitUntil(java.util.function.Supplier<Object>) where the supplier keeps returning null/false/0 — e.g. a predicate reading driver state (URL, element count, a flag) that never becomes satisfied within the timeout.

Common situations: Supplier logic bug (always false); condition depends on an external event (websocket, background job) that never fires; timeout too short for the operation being awaited; supplier throws internally and the wrapper keeps polling.

Understand the failure class

Background: Request timed out: what client-side request timeouts mean across libraries (Request timed out, TIMED_OUT, APITimeoutError) — this error's family across 39 libraries.

• Timeouts: ETIMEDOUT, deadlines, and hung requests — what actually expires when a request times out.

Related errors

• waitFor timeout
• waitForAny timeout
• waitForEnabled timeout
• waitForResultCount timeout
• waitForText timeout: expected

AI-assisted analysis of karatelabs/karate@a22eb90246 (2026-09-12). Data as JSON: /api/errors/3b545f447832e44e. Report an issue: GitHub.

Appendix: source

Thrown at karate-core/src/main/java/io/karatelabs/driver/w3c/W3cDriver.java:677

        throw new DriverException("waitUntil timeout: " + expression);
    }

    @Override
    public Object waitUntil(java.util.function.Supplier<Object> condition) {
        return waitUntil(condition, options.getTimeoutDuration());
    }

    @Override
    public Object waitUntil(java.util.function.Supplier<Object> condition, java.time.Duration timeout) {
        long deadline = System.currentTimeMillis() + timeout.toMillis();
        while (System.currentTimeMillis() < deadline) {
            Object result = condition.get();
            if (isTruthy(result)) {
                return result;
            }
            sleep(options.getRetryInterval());
        }
        throw new DriverException("waitUntil (supplier) timeout");
    }

    @Override
    public List<Element> waitForResultCount(String locator, int count) {
        return waitForResultCount(locator, count, options.getTimeoutDuration());
    }

    @Override
    public List<Element> waitForResultCount(String locator, int count, java.time.Duration timeout) {
        long deadline = System.currentTimeMillis() + timeout.toMillis();
        while (System.currentTimeMillis() < deadline) {
            List<Element> results = locateAll(locator);
            if (results.size() == count) {
                return results;
            }
            sleep(options.getRetryInterval());
        }
        throw new DriverException("waitForResultCount timeout: " + locator + " expected count: " + count);

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