Update the internal global TextMapPropagator

[MrAlias]

Include feedback from @seh in a post-merge review of #1258

[MrAlias]

@seh looks like you're not a member of @open-telemetry so I can't request a review from you in the automation, but would appreciate your feedback here.

[seh]

This looks good.

One alternative to consider: Introduce a function like this:

func (p *textMapPropagator) effectiveDelegate() otel.TextMapCarrier {
  if d := p.currentDelegate(); d != nil {
    return d
  }
  return p.noop
}

Then, in the three cases here, you would call it, for example,

  return p.effectiveDelegate().Inject(ctx, carrier)

[codecov]

Codecov Report

Merging #1261 into master will decrease coverage by 0.0%.
The diff coverage is 0.0%.

@@           Coverage Diff            @@
##           master   #1261     +/-   ##
========================================
- Coverage    76.4%   76.4%   -0.1%     
========================================
  Files         132     132             
  Lines        5928    5922      -6     
========================================
- Hits         4533    4528      -5     
+ Misses       1146    1143      -3     
- Partials      249     251      +2     

Impacted Files	Coverage Δ
api/global/internal/propagator.go	13.3% <0.0%> (+2.8%)	⬆️
sdk/trace/batch_span_processor.go	74.1% <0.0%> (-4.4%)	⬇️
trace_noop.go	53.3% <0.0%> (-3.9%)	⬇️
oteltest/span.go	97.2% <0.0%> (-2.8%)	⬇️
bridge/opentracing/internal/mock.go	71.6% <0.0%> (-2.7%)	⬇️
sdk/trace/span.go	92.9% <0.0%> (-2.1%)	⬇️
trace.go	80.5% <0.0%> (ø)
config.go	100.0% <0.0%> (ø)
bridge/opentracing/bridge.go	40.0% <0.0%> (+0.9%)	⬆️
oteltest/mock_span.go	12.5% <0.0%> (+4.8%)	⬆️

[seh]

looks like you're not a member of @open-telemetry

What does it take to become a member? Where do I send my check?

[MrAlias]

What does it take to become a member? Where do I send my check?

😆

Instructions are here. Please consider me as one of your sponsors when you submit your application.

[seh]

My vote doesn't count, but this looks good to me, modulo the one extra word in the documentation comment.

[Aneurysm9]

What does it take to become a member? Where do I send my check?

😆

Instructions are here. Please consider me as one of your sponsors when you submit your application.

Count me as a second sponsor!

[seh]

Please consider me as one of your sponsors when you submit your application.

Count me as a second sponsor!

It's been a while, but please see open-telemetry/community#695.