Test: Fix flaky leader index in waitLeader function
#188
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Signed-off-by: Xinyuan Du <[email protected]>
pav-kv
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Mar 23, 2024
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Fixes cockroachdb#127413. This commit bypasses the larger rebase in cockroachdb#122133 to pick up the test flake fix in etcd-io/raft#188. There was some discussion in etcd-io/raft#181 about alternatives for fixing this test. For now, we stick with a direct cherry-pick. Release note: None
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Sep 6, 2024
Fixes cockroachdb#127413. This commit bypasses the larger rebase in cockroachdb#122133 to pick up the test flake fix in etcd-io/raft#188. There was some discussion in etcd-io/raft#181 about alternatives for fixing this test. For now, we stick with a direct cherry-pick. Release note: None
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Sep 6, 2024
130084: raft: fix flaky leader index in waitLeader function r=pav-kv a=nvanbenschoten Fixes #127413. This commit bypasses the larger rebase in #122133 to pick up the test flake fix in etcd-io/raft#188. There was some discussion in etcd-io/raft#181 about alternatives for fixing this test. For now, we stick with a direct cherry-pick. Release note: None Co-authored-by: Nathan VanBenschoten <[email protected]>
nvanbenschoten
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Sep 6, 2024
Fixes cockroachdb#127413. This commit bypasses the larger rebase in cockroachdb#122133 to pick up the test flake fix in etcd-io/raft#188. There was some discussion in etcd-io/raft#181 about alternatives for fixing this test. For now, we stick with a direct cherry-pick. Release note: None
nvanbenschoten
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Sep 6, 2024
Fixes cockroachdb#127413. This commit bypasses the larger rebase in cockroachdb#122133 to pick up the test flake fix in etcd-io/raft#188. There was some discussion in etcd-io/raft#181 about alternatives for fixing this test. For now, we stick with a direct cherry-pick. Release note: None
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Summary
The
waitLeaderfunction currently has an issue where it returns the wrong leader index in certain scenarios. When iterating through nodes to find the leader, if the leader changes during the iteration, the function incorrectly returns the default value instead of the actual leader index.Example
In the function,
waitLeader:raft/rafttest/node_test.go
Lines 130 to 151 in e1bfcf7
Let's say,
iis 3 now, and we still don't have a leader elected.iis 4 now, and the leader of node[4] has changed from 0 to 1 in step2. Sol[lead] = struct{}{}will be executed. Butn.id == leadis false,lindexstill equals 0.len(l)now equals 1. This function will return lindex, which is 0. But 0 is not the real leader index, but the default value.Proposed Changes
To address this issue, the proposed solution involves initializing the
lindexvariable to -1 instead of 0. This change ensures thatlindexholds a distinct value indicating 'not found' rather than potentially conflating it with the index of the first element.Changes Made
lindexvariable to -1 instead of 0.Impact
This change ensures that the
waitLeaderfunction correctly returns the leader index, avoiding confusion between 'not found' and the index of the first element.Fixes #181