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fix(gax): adjust RetryAlgorithm logic for timeout v. exception #13243

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fix(gax): adjust RetryAlgorithm logic for timeout v. exception #13243

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d771365
fix(gax): adjust RetryAlgorithm logic for timeout v. exception
whowes May 20, 2026
901c2e7
test(gax): add tests for RetryAlgorithm changes
whowes May 20, 2026
aa95c0b
fix(gax): fix linter issues
whowes May 20, 2026
ddbfe1d
fix(gax): add assertion to test
whowes May 20, 2026
17c1ee4
Defer to timing-related exception in createNextAttempt instead of sho…
whowes May 21, 2026
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28 changes: 17 additions & 11 deletions sdk-platform-java/gax-java/gax/src/main/java/com/google/api/gax/retrying/RetryAlgorithm.java
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Original file line number Diff line number Diff line change
Expand Up @@ -153,19 +153,25 @@ public TimedAttemptSettings createNextAttempt(
Throwable previousThrowable,
ResponseT previousResponse,
TimedAttemptSettings previousSettings) {
// a small optimization that avoids calling relatively heavy methods
// like timedAlgorithm.createNextAttempt(), when it is not necessary.
if (!shouldRetryBasedOnResult(context, previousThrowable, previousResponse)) {
return null;
if (shouldRetryBasedOnResult(context, previousThrowable, previousResponse)) {
TimedAttemptSettings newSettings =
createNextAttemptBasedOnResult(
context, previousThrowable, previousResponse, previousSettings);
if (newSettings == null) {
newSettings = createNextAttemptBasedOnTiming(context, previousSettings);
}
return newSettings;
}

TimedAttemptSettings newSettings =
createNextAttemptBasedOnResult(
context, previousThrowable, previousResponse, previousSettings);
if (newSettings == null) {
newSettings = createNextAttemptBasedOnTiming(context, previousSettings);
// If we shouldn't retry based on result and the last attempt failed with an
// exception, defer to any exception thrown by shouldRetryBasedOnTiming.
// This lets a timeout-related exception get propagated when justified
// rather than e.g. exceptions caused by very short RPC deadlines on a
// final polling attempt.
Comment on lines +166 to +169

@lqiu96 lqiu96 Jun 3, 2026

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qq, I'm not sure I'm following this comment. I might not be understanding this fully.

What do you mean by defer to any exception thrown by shouldRetryBasedOnTiming`? Is this referring to an exception thrown by the ExponentialRetryAlgorithm?

IIRC, short RPC deadlines that can't be processed in time will result in a DEADLINE_EXCEEDED status code and that may or may not be retried as a retryable status code

@whowes whowes Jun 4, 2026

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"Is this referring to an exception thrown by the ExponentialRetryAlgorithm?" Not by ExponentialRetryAlgorithm itself, but by its subclass OperationTimedPollAlgorithm used for LRO polling, which throws a CancellationException when the cumulative timeout for all polls is exhausted.

With the current structure of RetryAlgorithm.createNextAttempt() the CancellationException-throwing codepath doesn't get reached if the final LRO polling RPC fails. That results in an ExecutionException getting propagated instead, which is misleading when that failure is triggered by an overly-truncated deadline. The mismatch of expectations is IMO likely at the root of the test flakes from #12373 and #3277.

if (previousThrowable != null) {
TimedAttemptSettings nextSettings = createNextAttemptBasedOnTiming(context, previousSettings);
shouldRetryBasedOnTiming(context, nextSettings);
}
return newSettings;
return null;
}

private TimedAttemptSettings createNextAttemptBasedOnResult(
Expand Down
58 changes: 58 additions & 0 deletions ...tform-java/gax-java/gax/src/test/java/com/google/api/gax/retrying/RetryAlgorithmTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -30,10 +30,14 @@
package com.google.api.gax.retrying;

import static org.junit.jupiter.api.Assertions.assertFalse;
import static org.junit.jupiter.api.Assertions.assertNull;
import static org.junit.jupiter.api.Assertions.assertThrows;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.never;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;

import java.util.concurrent.CancellationException;
import org.junit.jupiter.api.Test;

@SuppressWarnings({"unchecked", "deprecation"})
Expand Down Expand Up @@ -113,6 +117,45 @@ void testNextAttemptWithContext() {
verify(resultAlgorithm).shouldRetry(context, previousThrowable, previousResult);
}

@Test
void testCreateNextAttempt_exceptionAndTimeout_defersToTimingException() {
ResultRetryAlgorithm<Object> resultAlgorithm = mock(ResultRetryAlgorithm.class);
TimedRetryAlgorithm timedAlgorithm = mock(TimedRetryAlgorithm.class);
RetryAlgorithm<Object> algorithm = new RetryAlgorithm<>(resultAlgorithm, timedAlgorithm);
Throwable throwable = new Throwable();
Object result = new Object();
TimedAttemptSettings previousSettings = mock(TimedAttemptSettings.class);
TimedAttemptSettings nextSettings = mock(TimedAttemptSettings.class);

when(resultAlgorithm.shouldRetry(throwable, result)).thenReturn(false);
when(timedAlgorithm.createNextAttempt(previousSettings)).thenReturn(nextSettings);
when(timedAlgorithm.shouldRetry(nextSettings)).thenThrow(new CancellationException());

assertThrows(
CancellationException.class,
() -> algorithm.createNextAttempt(throwable, result, previousSettings));
}

@Test
void testCreateNextAttempt_exceptionAndNoTimeout_returnsNull() {
ResultRetryAlgorithm<Object> resultAlgorithm = mock(ResultRetryAlgorithm.class);
TimedRetryAlgorithm timedAlgorithm = mock(TimedRetryAlgorithm.class);
RetryAlgorithm<Object> algorithm = new RetryAlgorithm<>(resultAlgorithm, timedAlgorithm);
Throwable throwable = new Throwable();
Object result = new Object();
TimedAttemptSettings previousSettings = mock(TimedAttemptSettings.class);
TimedAttemptSettings nextSettings = mock(TimedAttemptSettings.class);

when(resultAlgorithm.shouldRetry(throwable, result)).thenReturn(false);
when(timedAlgorithm.createNextAttempt(previousSettings)).thenReturn(nextSettings);
when(timedAlgorithm.shouldRetry(nextSettings)).thenReturn(true);

TimedAttemptSettings nextAttemptSettings =
algorithm.createNextAttempt(throwable, result, previousSettings);

assertNull(nextAttemptSettings);
}

@Test
void testShouldRetry() {
ResultRetryAlgorithm<Object> resultAlgorithm = mock(ResultRetryAlgorithm.class);
Expand Down Expand Up @@ -201,4 +244,19 @@ void testShouldRetryWithContext_noPreviousSettings() {

assertFalse(algorithm.shouldRetry(context, previousThrowable, previousResult, null));
}

@Test
void testShouldRetry_resultFalseAndThrowableNull_shortCircuits() {
ResultRetryAlgorithm<Object> resultAlgorithm = mock(ResultRetryAlgorithm.class);
TimedRetryAlgorithm timedAlgorithm = mock(TimedRetryAlgorithm.class);
RetryAlgorithm<Object> algorithm = new RetryAlgorithm<>(resultAlgorithm, timedAlgorithm);
Object previousResult = new Object();
TimedAttemptSettings previousSettings = mock(TimedAttemptSettings.class);
when(resultAlgorithm.shouldRetry(null, previousResult)).thenReturn(false);

boolean shouldRetry = algorithm.shouldRetry(null, previousResult, previousSettings);

assertFalse(shouldRetry);
verify(timedAlgorithm, never()).shouldRetry(previousSettings);
}
}
9 changes: 7 additions & 2 deletions ...m-java/gax-java/gax/src/test/java/com/google/api/gax/rpc/StreamingRetryAlgorithmTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -116,12 +116,17 @@ void testNextAttemptReturnsNullWhenShouldNotRetry() {
StreamingRetryAlgorithm<String> algorithm =
new StreamingRetryAlgorithm<>(resultAlgorithm, timedAlgorithm);

TimedAttemptSettings previousSettings = mock(TimedAttemptSettings.class);
when(previousSettings.getGlobalSettings()).thenReturn(DEFAULT_RETRY_SETTINGS);
when(previousSettings.getRpcTimeoutDuration())
.thenReturn(DEFAULT_RETRY_SETTINGS.getInitialRpcTimeoutDuration());

TimedAttemptSettings attempt =
algorithm.createNextAttempt(context, exception, null, mock(TimedAttemptSettings.class));
algorithm.createNextAttempt(context, exception, null, previousSettings);
assertThat(attempt).isNull();

TimedAttemptSettings attemptWithoutContext =
algorithm.createNextAttempt(exception, null, mock(TimedAttemptSettings.class));
algorithm.createNextAttempt(exception, null, previousSettings);
assertThat(attemptWithoutContext).isNull();
}

Expand Down
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