feat(gax): enforce global timeout for resumable uploads

[whowes]

Enforces ResumableUploadCallSettings.getGlobalTimeout() in ResumableUploadChunkCoordinator across the upload lifecycle. Cancels in-flight RPCs and completes the future with DeadlineExceededException when the deadline is exceeded.

[gemini-code-assist]

Code Review

This pull request introduces global timeout handling for resumable uploads in ResumableUploadChunkCoordinator using a scheduled executor to trigger a DeadlineExceededException if the upload exceeds the specified duration. It also includes comprehensive unit tests to verify timeout behavior, clean cancellations, and payload stream closure. The review feedback highlights two key improvements: ensuring thread safety by reading uploadSessionUrl within a synchronized block in onTimeout(), and preventing potential test hangs by specifying timeouts on future.get() calls in the newly added unit tests.

[gemini-code-assist]

The field uploadSessionUrl is read outside of the synchronized (lock) block. If uploadSessionUrl is not declared volatile or is guarded by lock, this can lead to a data race and memory visibility issues across threads (e.g., the timeout thread might see a stale null value even after the session URL has been initialized). To ensure thread safety and consistent visibility, read uploadSessionUrl inside the synchronized (lock) block.

  private void onTimeout() {
    String sessionUrl;
    synchronized (lock) {
      if (done) {
        return;
      }
      sessionUrl = uploadSessionUrl;
    }
    String message =
        sessionUrl != null
            ? "Resumable upload timed out for session: " + sessionUrl
            : "Resumable upload timed out before session initiation completed";
    finish(null, new DeadlineExceededException(message, null, TIMEOUT_STATUS_CODE, false));
  }

[gemini-code-assist]

Calling future.get() without a timeout in a timeout-related unit test can cause the test suite to hang indefinitely if the timeout mechanism fails to fire. It is a best practice to always specify a timeout (e.g., 5 seconds) when waiting on futures in tests to prevent blocking the CI/CD pipeline.

Suggested change

	ExecutionException exception = assertThrows(ExecutionException.class, future::get);
	ExecutionException exception = assertThrows(ExecutionException.class, () -> future.get(5, TimeUnit.SECONDS));

[sonarqubecloud]

Quality Gate passed for 'gapic-generator-java-root'

Issues
9 New issues
0 Accepted issues

Measures
0 Security Hotspots
86.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[sonarqubecloud]

Quality Gate failed for 'gapic-generator-java-root'

Failed conditions
0.0% Coverage on New Code (required ≥ 80%)

See analysis details on SonarQube Cloud