Fix flake replicas different ranks test

[hanxizh9910]

Closes #2683

For the test, I found two problems.

1. Test Assumes Winner Has Rank #0

In my test run, in the failing case:

• Replica -3 (rank 0) won epoch 10 first
• Replica -6 (rank 1) won epoch 11 second
• Replica -3 saw higher epoch and stepped down
• Final result: rank 1 became master

Rank #0 doesn't guarantee being the final master.

2. Pattern Matching Bug

The pattern *Start of election*rank #0* incorrectly matches "primary rank #0":

Log: Start of election delayed for 350 milliseconds (rank #1, primary rank #0, offset 2172)

This line has rank #1, but the pattern matches because of "primary rank #0" at the end.

This is the test example. I added some print statements in the test

Solution

• Fixed the format problem by checking if (rank #0 or (rank #1 so that we won't accidentally match the primary rank
• Only check to make sure replica 3 and replica 6 have different ranks without assuming the replica with rank 0 will become the master.

Test

I ran it for 1000 times: https://github.com/hanxizh9910/valkey/actions/runs/21705632232

[enjoy-binbin]

I'm thinking we might be able to avoid this problem within the cluster code, R6 shouldn't actually be able to initiate an election with a new epoch. The one of the purpose of the test is to ensure that the replica with rank 0 can win. Let me think about it some more.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 74.97%. Comparing base (9f374e1) to head (b85a348).
⚠️ Report is 3 commits behind head on unstable.

Additional details and impacted files

@@             Coverage Diff              @@
##           unstable    #3164      +/-   ##
============================================
+ Coverage     74.87%   74.97%   +0.09%     
============================================
  Files           129      129              
  Lines         71309    71318       +9     
============================================
+ Hits          53393    53468      +75     
+ Misses        17916    17850      -66     

see 20 files with indirect coverage changes

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[enjoy-binbin]

emm, look like we can't (or unable to find out in a short time). I am merging it, it is a good fix, thank you.

[sarthakaggarwal97]

Thanks @hanxizh9910!