github.com/quic-go/qpack v0.5.1: HeaderField

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 github.com/quic-go/qpack.HeaderField in pkg:golang/github.com/quic-go/qpack@v0.5.1
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/quic-go/qpack@v0.5.1
Demonstrate these symbols/APIs:
  - github.com/quic-go/qpack.HeaderField

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.

package sample_test

import (
	"bytes"
	"reflect"
	"testing"

	"github.com/quic-go/qpack"
)

func TestHeaderField(t *testing.T) {
	// 1. HeaderField struct stores Name and Value string pairs representing HTTP/3 headers
	hf := qpack.HeaderField{
		Name:  "content-type",
		Value: "application/json",
	}
	if hf.Name != "content-type" || hf.Value != "application/json" {
		t.Fatalf("HeaderField fields not preserved: got Name=%q, Value=%q", hf.Name, hf.Value)
	}

	// 2. HeaderField.IsPseudo returns true for HTTP/3 pseudo-headers starting with a colon and false for standard and custom headers
	pseudoHeaders := []qpack.HeaderField{
		{Name: ":status", Value: "200"},
		{Name: ":method", Value: "GET"},
		{Name: ":path", Value: "/index.html"},
		{Name: ":scheme", Value: "https"},
		{Name: ":authority", Value: "example.com"},
	}
	for _, p := range pseudoHeaders {
		if !p.IsPseudo() {
			t.Fatalf("expected HeaderField %q to be identified as pseudo-header", p.Name)
		}
	}

	regularHeaders := []qpack.HeaderField{
		{Name: "content-type", Value: "application/json"},
		{Name: "authorization", Value: "Bearer token"},
		{Name: "x-custom-header", Value: "custom-value"},
		{Name: "accept-encoding", Value: "gzip, deflate, br"},
	}
	for _, r := range regularHeaders {
		if r.IsPseudo() {
			t.Fatalf("expected HeaderField %q not to be identified as pseudo-header", r.Name)
		}
	}

	// 3. Encoder.WriteField encodes HeaderField instances into QPACK wire format
	var buf bytes.Buffer
	enc := qpack.NewEncoder(&buf)

	allHeaders := append(pseudoHeaders, regularHeaders...)
	for _, field := range allHeaders {
		if err := enc.WriteField(field); err != nil {
			t.Fatalf("failed to write HeaderField %v: %v", field, err)
		}
	}
	if err := enc.Close(); err != nil {
		t.Fatalf("failed to close encoder: %v", err)
	}
	if buf.Len() == 0 {
		t.Fatalf("expected non-empty encoded QPACK bytes")
	}

	// 4. Decoder.DecodeFull decodes QPACK wire format into a slice of HeaderField structs with exact Name and Value preservation
	dec := qpack.NewDecoder(func(f qpack.HeaderField) {})
	decodedFields, err := dec.DecodeFull(buf.Bytes())
	if err != nil {
		t.Fatalf("failed to decode header block: %v", err)
	}
	if !reflect.DeepEqual(decodedFields, allHeaders) {
		t.Fatalf("decoded HeaderFields mismatch:\ngot:  %+v\nwant: %+v", decodedFields, allHeaders)
	}

	// 5. NewDecoder emitFunc receives parsed HeaderField structs during stream decoding
	var emittedFields []qpack.HeaderField
	streamDec := qpack.NewDecoder(func(f qpack.HeaderField) {
		emittedFields = append(emittedFields, f)
	})
	if _, err := streamDec.Write(buf.Bytes()); err != nil {
		t.Fatalf("failed to write to stream decoder: %v", err)
	}
	if err := streamDec.Close(); err != nil {
		t.Fatalf("failed to close stream decoder: %v", err)
	}
	if !reflect.DeepEqual(emittedFields, allHeaders) {
		t.Fatalf("stream emitted HeaderFields mismatch:\ngot:  %+v\nwant: %+v", emittedFields, allHeaders)
	}
}

{"case":{"caseId":"case:sha256:79ff09831ce685d1989b3e5f378fc4d38ee8a5f8be3773c3991ba43fe5d7d4a7","contract":["HeaderField struct stores Name and Value string pairs representing HTTP/3 headers","HeaderField.IsPseudo returns true for HTTP/3 pseudo-headers starting with a colon and false for standard and custom headers","Encoder.WriteField encodes HeaderField instances into QPACK wire format","Decoder.DecodeFull decodes QPACK wire format into a slice of HeaderField structs with exact Name and Value preservation","NewDecoder emitFunc receives parsed HeaderField structs during stream decoding"],"goal":"verify github.com/quic-go/qpack.HeaderField in pkg:golang/github.com/quic-go/qpack@v0.5.1","kind":"HOW","packages":["pkg:golang/github.com/quic-go/qpack@v0.5.1"],"schemaVersion":1,"symbols":["github.com/quic-go/qpack.HeaderField"]},"contractCommand":["go","test","-v","./..."],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","language":"go","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","packageManagerVersion":"1.26.6","runtime":"go","runtimeVersion":"1.26.6","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/github.com/quic-go/qpack@v0.5.1"],"schemaVersion":1,"subject":"pkg:golang/github.com/quic-go/qpack@v0.5.1","symbols":["github.com/quic-go/qpack.HeaderField"],"verifierAdapter":"golang@1"}

module sample

go 1.26.6

require github.com/quic-go/qpack v0.5.1

require golang.org/x/net v0.28.0 // 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/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
github.com/quic-go/qpack v0.5.1 h1:giqksBPnT/HDtZ6VhtFKgoLOWmlyo9Ei6u9PqzIMbhI=
github.com/quic-go/qpack v0.5.1/go.mod h1:+PC4XFrEskIVkcLzpEkbLqq1uCoxPhQuvK5rH1ZgaEg=
github.com/quic-go/qpack v0.6.0 h1:g7W+BMYynC1LbYLSqRt8PBg5Tgwxn214ZZR34VIOjz8=
github.com/quic-go/qpack v0.6.0/go.mod h1:lUpLKChi8njB4ty2bFLX2x4gzDqXwUpaO1DP9qMDZII=
github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
golang.org/x/net v0.28.0 h1:a9JDOJc5GMUJ0+UDqmLT86WiEy7iWyIhz8gz8E4e5hE=
golang.org/x/net v0.28.0/go.mod h1:yqtgsTWOOnlGLG9GFRrK3++bGOUEkNBoHZc8MEDWPNg=
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 github.com/quic-go/qpack.HeaderField in pkg:golang/github.com/quic-go/qpack@v0.5.1",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/quic-go/qpack@v0.5.1"
  ],
  "symbols": [
    "github.com/quic-go/qpack.HeaderField"
  ]
}