client: prevent keyspace client from panic

[rleungx]

What problem does this PR solve?

Issue Number: Ref #7902.

What is changed and how does it work?

Check List

Tests

• Unit test

Release note

None.

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• CabinfeverB
• HuSharp

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[codecov]

Codecov Report

Merging #7899 (cbfbb3a) into master (bbd3bdb) will decrease coverage by 0.04%.
Report is 1 commits behind head on master.
The diff coverage is 40.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #7899      +/-   ##
==========================================
- Coverage   73.45%   73.41%   -0.04%     
==========================================
  Files         434      434              
  Lines       48067    48079      +12     
==========================================
- Hits        35306    35299       -7     
- Misses       9718     9730      +12     
- Partials     3043     3050       +7     

Flag	Coverage Δ
unittests	73.41% <40.00%> (-0.04%)	⬇️

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[rleungx]

/merge

[ti-chi-bot]

@rleungx: It seems you want to merge this PR, I will help you trigger all the tests:

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[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: cbfbb3a