RATIS-2518. Make testInstallSnapshotDuringBootstrap diagnostics fail-safe.

[slfan1989]

What changes were proposed in this pull request?

This is a follow-up to RATIS-2501.

RATIS-2501 added additional diagnostics for testInstallSnapshotDuringBootstrap failures. However, the diagnostic path may access raft log state from a peer whose raft log has already been closed. When this happens, dumpClusterState() can throw a secondary IllegalStateException, which hides the original failure that the diagnostics were intended to explain.

This patch makes dumpClusterState() fail-safe by safely collecting diagnostic values. If a diagnostic value is unavailable, it is logged as unavailable: <exception> instead of throwing from the diagnostic path.

What is the link to the Apache JIRA

JIRA: RATIS-2518. Make testInstallSnapshotDuringBootstrap diagnostics fail-safe.

How was this patch tested?

Tested with:

./mvnw -pl ratis-test -am -Pgrpc-tests -Dtest=TestInstallSnapshotNotificationWithGrpc#testInstallSnapshotDuringBootstrap test

Result:

[INFO] -------------------------------------------------------
[INFO]  T E S T S
[INFO] -------------------------------------------------------
[INFO] Running org.apache.ratis.grpc.TestInstallSnapshotNotificationWithGrpc
[INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 6.33 s - in org.apache.ratis.grpc.TestInstallSnapshotNotificationWithGrpc
[INFO] 
[INFO] Results:
[INFO] 
[INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0
[INFO] 
[INFO] ------------------------------------------------------------------------

[github-actions]

This PR has been marked as stale due to 60 days of inactivity. Please comment or remove the stale label to keep it open. Otherwise, it will be automatically closed in ~30 days.