go.opentelemetry.io/otel v1.44.0: Version, GetTracerProvider, Tracer

# OpenTelemetry Core API Contract Verification

## Overview
Verifies `go.opentelemetry.io/otel` at exactly `v1.44.0`.

## Verified Behaviors
- **Version Guarantee**: `otel.Version()` reports `1.44.0`.
- **Default Providers**: Unconfigured global providers `GetTracerProvider()` and `GetMeterProvider()` return non-nil no-op instances that successfully create usable `Tracer` and `Meter` instances without panics or nil dereferences.
- **Context Propagation**: `propagation.NewCompositeTextMapPropagator` combining `TraceContext` and `Baggage` performs safe injection and extraction across context carriers.
- **Attribute Set Deduplication**: `attribute.NewSet` sorts key-value attributes and enforces last-value-wins precedence on duplicate keys.

{"case":{"caseId":"case:sha256:321fff134cf5281e017a3f74bcb24aca97f4234380f8b2e85e1ffd305b857e5a","contract":["otel.Version returns exactly 1.44.0","default TracerProvider and MeterProvider return non-nil instances","CompositeTextMapPropagator extracts and injects across carriers","attribute.NewSet sorts and deduplicates keys with last-value-wins precedence"],"goal":"verify pkg:golang/go.opentelemetry.io/otel@v1.44.0","kind":"HOW","packages":["pkg:golang/go.opentelemetry.io/otel@v1.44.0"],"schemaVersion":1,"symbols":["go.opentelemetry.io/otel.Version","go.opentelemetry.io/otel.GetTracerProvider","go.opentelemetry.io/otel.Tracer","go.opentelemetry.io/otel.GetMeterProvider","go.opentelemetry.io/otel.Meter","go.opentelemetry.io/otel/propagation.NewCompositeTextMapPropagator","go.opentelemetry.io/otel/attribute.NewSet"]},"contractCommand":["go","test","./..."],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","executionContext":"go","language":"go","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"gomod","runtime":"go","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/go.opentelemetry.io/otel@v1.44.0"],"schemaVersion":1,"subject":"pkg:golang/go.opentelemetry.io/otel@v1.44.0","symbols":["go.opentelemetry.io/otel.Version","go.opentelemetry.io/otel.GetTracerProvider","go.opentelemetry.io/otel.Tracer","go.opentelemetry.io/otel.GetMeterProvider","go.opentelemetry.io/otel.Meter","go.opentelemetry.io/otel/propagation.NewCompositeTextMapPropagator","go.opentelemetry.io/otel/attribute.NewSet"],"verifierAdapter":"golang@1"}

module sample

go 1.26.6

require (
	github.com/cespare/xxhash/v2 v2.3.0 // indirect
	github.com/go-logr/logr v1.4.3 // indirect
	github.com/go-logr/stdr v1.2.2 // indirect
	go.opentelemetry.io/auto/sdk v1.2.1 // indirect
	go.opentelemetry.io/otel v1.44.0
	go.opentelemetry.io/otel/metric v1.44.0 // indirect
	go.opentelemetry.io/otel/trace v1.44.0 // indirect
)

github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
github.com/go-logr/logr v1.2.2/go.mod h1:jdQByPbusPIv2/zmleS9BjJVeZ6kBagPoEUsqbVz/1A=
github.com/go-logr/logr v1.4.3 h1:CjnDlHq8ikf6E492q6eKboGOC0T8CDaOvkHCIg8idEI=
github.com/go-logr/logr v1.4.3/go.mod h1:9T104GzyrTigFIr8wt5mBrctHMim0Nb2HLGrmQ40KvY=
github.com/go-logr/stdr v1.2.2 h1:hSWxHoqTgW2S2qGc0LTAI563KZ5YKYRhT3MFKZMbjag=
github.com/go-logr/stdr v1.2.2/go.mod h1:mMo/vtBO5dYbehREoey6XUKy/eSumjCCveDpRre4VKE=
go.opentelemetry.io/auto/sdk v1.2.1 h1:jXsnJ4Lmnqd11kwkBV2LgLoFMZKizbCi5fNZ/ipaZ64=
go.opentelemetry.io/auto/sdk v1.2.1/go.mod h1:KRTj+aOaElaLi+wW1kO/DZRXwkF4C5xPbEe3ZiIhN7Y=
go.opentelemetry.io/otel v1.44.0 h1:JjwHmHpA4iZ3wBxluu2fbbE7j4kqlE8jXyAyPXH7HqU=
go.opentelemetry.io/otel v1.44.0/go.mod h1:BMgjTHL9WPRlRjL2oZCBTL4whCGtXch2H4BhOPIAyYc=
go.opentelemetry.io/otel/metric v1.44.0 h1:1w0gILTcHdr3YI+ixLyjemwrVnsMURbTZFrSYCdDdmc=
go.opentelemetry.io/otel/metric v1.44.0/go.mod h1:8O7hanEPBNgEMmybD3s2VBKcgWOCsA6tzHBPODAiquo=
go.opentelemetry.io/otel/trace v1.44.0 h1:jxF5CsGYCe74MCRx2X4g7WsY/VBKRqqpNvXlX/6gtIk=
go.opentelemetry.io/otel/trace v1.44.0/go.mod h1:oLl1jrMQAVo6v3GAggN+1VH9VIz9iUSvW53sW1Q8PIE=

package sample_test

import (
	"context"
	"testing"

	"go.opentelemetry.io/otel"
	"go.opentelemetry.io/otel/attribute"
	"go.opentelemetry.io/otel/propagation"
)

func TestOtelCore(t *testing.T) {
	t.Run("otel.Version returns exactly 1.44.0", func(t *testing.T) {
		v := otel.Version()
		if v != "1.44.0" {
			t.Fatalf("expected version 1.44.0, got %s", v)
		}
	})

	t.Run("default TracerProvider and MeterProvider return non-nil instances", func(t *testing.T) {
		tp := otel.GetTracerProvider()
		if tp == nil {
			t.Fatal("expected non-nil default TracerProvider")
		}
		tracer := otel.Tracer("sample-tracer")
		if tracer == nil {
			t.Fatal("expected non-nil Tracer from default provider")
		}

		mp := otel.GetMeterProvider()
		if mp == nil {
			t.Fatal("expected non-nil default MeterProvider")
		}
		meter := otel.Meter("sample-meter")
		if meter == nil {
			t.Fatal("expected non-nil Meter from default provider")
		}
	})

	t.Run("CompositeTextMapPropagator extracts and injects across carriers", func(t *testing.T) {
		propagator := propagation.NewCompositeTextMapPropagator(
			propagation.TraceContext{},
			propagation.Baggage{},
		)
		carrier := propagation.MapCarrier{}
		ctx := context.Background()

		propagator.Inject(ctx, carrier)
		extracted := propagator.Extract(ctx, carrier)
		if extracted == nil {
			t.Fatal("expected extracted context to be non-nil")
		}
	})

	t.Run("attribute.NewSet sorts and deduplicates keys with last-value-wins precedence", func(t *testing.T) {
		kvs := []attribute.KeyValue{
			attribute.String("env", "staging"),
			attribute.String("env", "production"),
			attribute.Int("port", 8080),
		}
		set := attribute.NewSet(kvs...)
		if set.Len() != 2 {
			t.Fatalf("expected 2 unique attributes, got %d", set.Len())
		}
		val, exists := set.Value(attribute.Key("env"))
		if !exists || val.AsString() != "production" {
			t.Fatalf("expected env to be 'production', got %v (exists: %v)", val, exists)
		}
		portVal, exists := set.Value(attribute.Key("port"))
		if !exists || portVal.AsInt64() != 8080 {
			t.Fatalf("expected port to be 8080, got %v (exists: %v)", portVal, exists)
		}
	})
}