The waitLeader function 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.
i is 3 now, and we still don't have a leader elected.
Then node[1] is elected as a leader,
i is 4 now, and the leader of node[4] has changed from 0 to 1 in step2. So l[lead] = struct{}{} will be executed. But n.id == lead is false, lindex still equals 0.
The iteration ends, and 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 lindex variable to -1 instead of 0. This change ensures that lindex holds a distinct value indicating 'not found' rather than potentially conflating it with the index of the first element.
Changes Made
Initialized lindex variable to -1 instead of 0.
Impact
This change ensures that the waitLeader function correctly returns the leader index, avoiding confusion between 'not found' and the index of the first element.
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: https://github.com/etcd-io/raft/blob/e1bfcf718c72ad64e12fcfd867bb012f19a14694/rafttest/node_test.go#L130-L151Let'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