fix(store/odsq4): fix order of opened flag stored

[walldiss]

Opened bool was stored before actual value of q4 was updated, which made it possible for concurrent reader to read nil value before it was updated.

Alternatively code can be refactored to use RWMutex instead of Mutex+atomic.Bool, which can improve readability of logic.

[cristaloleg]

Sounds like sync.Once to me. However it's up to you.

[cristaloleg]

SGTM

[walldiss]

We need to store state here for stored q4 to be able to know if we need to close it or not. sync.Once doesn't allow to read if it was executed or not.

[Wondertan]

@cristaloleg, see this golang/go#41690

[cristaloleg]

@Wondertan see this https://pkg.go.dev/sync#OnceValue

[Wondertan]

good catch!

[Wondertan]

@cristaloleg, this does not work for this case we need, unfortunately. We need to know if the once actually happened, while the OnceValue only gives a memoized value, which might be zero or not on its own

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 60.00000% with 2 lines in your changes missing coverage. Please review.

Please upload report for BASE (shwap@15ebe17). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
store/file/ods_q4.go	60.00%	0 Missing and 2 partials ⚠️

Additional details and impacted files

@@           Coverage Diff            @@
##             shwap    #3735   +/-   ##
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  Coverage         ?   46.68%           
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  Files            ?      314           
  Lines            ?    17820           
  Branches         ?        0           
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  Hits             ?     8319           
  Misses           ?     8490           
  Partials         ?     1011           

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