HttpTraceContext requires version 00

[kintel]

From reading code, it looks like we require the traceparent version to be 00:
https://github.com/open-telemetry/opentelemetry-js/blob/master/packages/opentelemetry-core/src/context/propagation/HttpTraceContext.ts#L30

The W3C spec says that we should still attempt to parse the known fields, as future extensions will be additive:
https://www.w3.org/TR/trace-context/#versioning-of-traceparent

This should probably be fixed by allowing any 2-digit lower-case hex value except ff.

While at it, we should also verify that we accept any additional data in the header, given that the first extra character is -.

Perhaps glance at the Go implementation, which has better compliance: https://github.com/open-telemetry/opentelemetry-go/blob/669d4b3a6c8d01821a65026f49df1b85d2972c14/api/trace/trace_context_propagator.go#L39

[mayurkale22]

Thanks for reporting this! Yes, you're right. We should replace 00 => [\da-f]{2} or something like this.

[mayurkale22]

If you are feeling motivated, maybe you can attempt to write solution and open a PR.

[kintel]

I'll have a look once I get my C++ implementation solid. ..and I may have to open this issue against every language in Otel : /