go.opentelemetry.io/otel/trace v1.38.0: NewSpanContext

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify go.opentelemetry.io/otel/trace.NewSpanContext in pkg:golang/go.opentelemetry.io/otel/trace@v1.38.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/go.opentelemetry.io/otel/trace@v1.38.0
Demonstrate these symbols/APIs:
  - go.opentelemetry.io/otel/trace.NewSpanContext

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:de93c8230ad5e9e995d6a0741fc109a96ac98348595b36877104138bdbb80bd7","contract":["NewSpanContext constructs a valid SpanContext when both TraceID and SpanID are non-zero, preserving TraceFlags, TraceState, and Remote status from SpanContextConfig","NewSpanContext returns an invalid SpanContext when either TraceID or SpanID is zero while still reporting partial presence via HasTraceID and HasSpanID","SpanContext instances constructed with identical SpanContextConfig compare Equal and remain immutable when derived copies are created via WithRemote"],"goal":"verify go.opentelemetry.io/otel/trace.NewSpanContext in pkg:golang/go.opentelemetry.io/otel/trace@v1.38.0","kind":"HOW","packages":["pkg:golang/go.opentelemetry.io/otel/trace@v1.38.0"],"schemaVersion":1,"symbols":["go.opentelemetry.io/otel/trace.NewSpanContext"]},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/go.opentelemetry.io/otel/trace@v1.38.0"],"schemaVersion":1,"subject":"pkg:golang/go.opentelemetry.io/otel/trace@v1.38.0","symbols":["go.opentelemetry.io/otel/trace.NewSpanContext"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.23.0

require go.opentelemetry.io/otel/trace v1.38.0

require go.opentelemetry.io/otel v1.38.0 // indirect

github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
go.opentelemetry.io/otel v1.38.0 h1:RkfdswUDRimDg0m2Az18RKOsnI8UDzppJAtj01/Ymk8=
go.opentelemetry.io/otel v1.38.0/go.mod h1:zcmtmQ1+YmQM9wrNsTGV/q/uyusom3P8RxwExxkZhjM=
go.opentelemetry.io/otel/trace v1.38.0 h1:Fxk5bKrDZJUH+AMyyIXGcFAPah0oRcT+LuNtJrmcNLE=
go.opentelemetry.io/otel/trace v1.38.0/go.mod h1:j1P9ivuFsTceSWe1oY+EeW3sc+Pp42sO++GHkg4wwhs=
gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

{
  "schemaVersion": 1,
  "goal": "verify go.opentelemetry.io/otel/trace.NewSpanContext in pkg:golang/go.opentelemetry.io/otel/trace@v1.38.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/go.opentelemetry.io/otel/trace@v1.38.0"
  ],
  "symbols": [
    "go.opentelemetry.io/otel/trace.NewSpanContext"
  ]
}

package main

import (
	"fmt"
	"os"

	"go.opentelemetry.io/otel/trace"
)

func assert(cond bool, msg string) {
	if !cond {
		fmt.Fprintln(os.Stderr, "assertion failed:", msg)
		os.Exit(1)
	}
}

func main() {
	traceID, err := trace.TraceIDFromHex("4bf92f3577b34da6a3ce929d0e0e4736")
	assert(err == nil, "TraceIDFromHex should succeed for valid 32-char hex")

	spanID, err := trace.SpanIDFromHex("00f067aa0ba902b7")
	assert(err == nil, "SpanIDFromHex should succeed for valid 16-char hex")

	ts, err := trace.ParseTraceState("rojo=00f067aa0ba902b7")
	assert(err == nil, "ParseTraceState should succeed for valid W3C member")

	// 1. Full valid SpanContextConfig via NewSpanContext
	cfg := trace.SpanContextConfig{
		TraceID:    traceID,
		SpanID:     spanID,
		TraceFlags: trace.FlagsSampled,
		TraceState: ts,
		Remote:     true,
	}
	sc := trace.NewSpanContext(cfg)
	assert(sc.IsValid(), "NewSpanContext with non-zero TraceID and SpanID must be valid")
	assert(sc.HasTraceID(), "HasTraceID must be true")
	assert(sc.HasSpanID(), "HasSpanID must be true")
	assert(sc.TraceID() == traceID, "TraceID must match configured TraceID")
	assert(sc.SpanID() == spanID, "SpanID must match configured SpanID")
	assert(sc.TraceFlags() == trace.FlagsSampled, "TraceFlags must match FlagsSampled")
	assert(sc.IsSampled(), "IsSampled must be true when FlagsSampled is set")
	assert(sc.TraceState().Get("rojo") == "00f067aa0ba902b7", "TraceState must preserve configured member")
	assert(sc.IsRemote(), "IsRemote must be true when Remote is set in SpanContextConfig")

	// 2. Partial and zero SpanContextConfig validity requirements
	emptySC := trace.NewSpanContext(trace.SpanContextConfig{})
	assert(!emptySC.IsValid(), "NewSpanContext with zero config must be invalid")
	assert(!emptySC.HasTraceID(), "zero config must not have TraceID")
	assert(!emptySC.HasSpanID(), "zero config must not have SpanID")
	assert(!emptySC.IsSampled(), "zero config must not be sampled")
	assert(!emptySC.IsRemote(), "zero config must not be remote")

	traceOnlySC := trace.NewSpanContext(trace.SpanContextConfig{TraceID: traceID})
	assert(traceOnlySC.HasTraceID(), "traceOnlySC must report HasTraceID true")
	assert(!traceOnlySC.HasSpanID(), "traceOnlySC must report HasSpanID false")
	assert(!traceOnlySC.IsValid(), "NewSpanContext with zero SpanID must be invalid")

	spanOnlySC := trace.NewSpanContext(trace.SpanContextConfig{SpanID: spanID})
	assert(!spanOnlySC.HasTraceID(), "spanOnlySC must report HasTraceID false")
	assert(spanOnlySC.HasSpanID(), "spanOnlySC must report HasSpanID true")
	assert(!spanOnlySC.IsValid(), "NewSpanContext with zero TraceID must be invalid")

	// 3. Equality and immutability of SpanContext created by NewSpanContext
	identicalSC := trace.NewSpanContext(cfg)
	assert(sc.Equal(identicalSC), "NewSpanContext with identical config must be Equal")

	localCopy := sc.WithRemote(false)
	assert(!localCopy.IsRemote(), "WithRemote(false) copy must report IsRemote false")
	assert(sc.IsRemote(), "original SpanContext from NewSpanContext must remain immutable")
	assert(!sc.Equal(localCopy), "SpanContext with different Remote flag must not be Equal")
}