fix(otelzap): write core.ctx only when init

[okhowang]

Fix #7367

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: okhowang (8bb35fe)
• ✅ login: dmathieu / name: Damien Mathieu (efbaed5)
• ✅ login: pellared / name: Robert Pająk (f4a5cff)

[pellared]

Can you please add a changelog entry?

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 81.6%. Comparing base (b2aa398) to head (efbaed5).
Report is 1 commits behind head on main.

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #7368   +/-   ##
=====================================
  Coverage   81.6%   81.6%           
=====================================
  Files        205     205           
  Lines      18186   18187    +1     
=====================================
+ Hits       14840   14844    +4     
+ Misses      2924    2922    -2     
+ Partials     422     421    -1     

Files with missing lines	Coverage Δ
bridges/otelzap/core.go	97.9% <100.0%> (+<0.1%)	⬆️

... and 1 file with indirect coverage changes

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[khushijain21]

Thanks for catching this!

[dmathieu]

Could this be tested?

[okhowang]

Could this be tested?

it can be found by go test -race, and adding a test to call Write with context.Context field in two goroutine.

[dmathieu]

Sure, but the CI does run go test with -race and doesn't fail on the main branch.

[pellared]

Could this be tested?

it can be found by go test -race, and adding a test to call Write with context.Context field in two goroutine.

Can you add such test?
Notice https://github.com/open-telemetry/opentelemetry-go/blob/main/CONTRIBUTING.md#testing:

Use the term ConcurrentSafe in the test name when it aims to verify the absence of race conditions.

[okhowang]

test case added

[dmathieu]

This looks good, we now only need a changelog entry 😸