github.com/quic-go/go-ossfuzz-seeds v0.1.0: ErrUnencodableDynamicCorpusArgs

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/go-ossfuzz-seeds.ErrUnencodableDynamicCorpusArgs in pkg:golang/github.com/quic-go/go-ossfuzz-seeds@v0.1.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/quic-go/go-ossfuzz-seeds@v0.1.0
Demonstrate these symbols/APIs:
  - github.com/quic-go/go-ossfuzz-seeds.ErrUnencodableDynamicCorpusArgs

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:sha256:46fb7eecf76183efe1cb41e666543861798a1611e3aa937ba357ea51d0809bf6","contract":["ErrUnencodableDynamicCorpusArgs is a non-nil sentinel error indicating that dynamic arguments cannot be encoded for OSS-Fuzz.","CorpusEntry returns an error wrapping ErrUnencodableDynamicCorpusArgs when dynamic argument lengths cannot be represented by byte-sized weights.","errors.Is matches the error returned by CorpusEntry against ErrUnencodableDynamicCorpusArgs when dynamic argument lengths are unencodable.","The error message returned by CorpusEntry includes the sentinel error description and dynamic argument lengths.","CorpusEntry returns a non-empty byte slice and nil error when valid dynamic arguments are provided."],"goal":"verify github.com/quic-go/go-ossfuzz-seeds.ErrUnencodableDynamicCorpusArgs in pkg:golang/github.com/quic-go/go-ossfuzz-seeds@v0.1.0","kind":"HOW","packages":["pkg:golang/github.com/quic-go/go-ossfuzz-seeds@v0.1.0"],"schemaVersion":1,"symbols":["github.com/quic-go/go-ossfuzz-seeds.ErrUnencodableDynamicCorpusArgs"]},"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/github.com/quic-go/go-ossfuzz-seeds@v0.1.0"],"schemaVersion":1,"subject":"pkg:golang/github.com/quic-go/go-ossfuzz-seeds@v0.1.0","symbols":["github.com/quic-go/go-ossfuzz-seeds.ErrUnencodableDynamicCorpusArgs"],"verifierAdapter":"golang@1"}

module example.com/ossfuzzseeds

go 1.26.6

require github.com/quic-go/go-ossfuzz-seeds v0.1.0

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/go-ossfuzz-seeds v0.1.0 h1:APacT+iIaNF6fd8AGEiN3bT/Jtkd2jz4v4TzM7MFjy0=
github.com/quic-go/go-ossfuzz-seeds v0.1.0/go.mod h1:3IOHRbJIc+L6YKMwfDtJAM9Vj9k0YY4muhuyUYk5tbk=
github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
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/go-ossfuzz-seeds.ErrUnencodableDynamicCorpusArgs in pkg:golang/github.com/quic-go/go-ossfuzz-seeds@v0.1.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/quic-go/go-ossfuzz-seeds@v0.1.0"
  ],
  "symbols": [
    "github.com/quic-go/go-ossfuzz-seeds.ErrUnencodableDynamicCorpusArgs"
  ]
}

package main

import (
	"errors"
	"fmt"
	"os"
	"strings"

	ossfuzzseeds "github.com/quic-go/go-ossfuzz-seeds"
)

func assert(condition bool, message string) {
	if !condition {
		fmt.Fprintf(os.Stderr, "assertion failed: %s\n", message)
		os.Exit(1)
	}
}

func main() {
	// Assertion 1: ErrUnencodableDynamicCorpusArgs is a non-nil sentinel error indicating that dynamic arguments cannot be encoded for OSS-Fuzz.
	{
		assert(ossfuzzseeds.ErrUnencodableDynamicCorpusArgs != nil, "ErrUnencodableDynamicCorpusArgs must not be nil")
		assert(ossfuzzseeds.ErrUnencodableDynamicCorpusArgs.Error() == "dynamic corpus arguments can't be encoded for OSS-Fuzz",
			"unexpected ErrUnencodableDynamicCorpusArgs error string")
	}

	// Assertion 2: CorpusEntry returns an error wrapping ErrUnencodableDynamicCorpusArgs when dynamic argument lengths cannot be represented by byte-sized weights.
	{
		arg1 := make([]byte, 1)
		arg2 := make([]byte, 1)
		arg3 := make([]byte, 100000)

		entry, err := ossfuzzseeds.CorpusEntry(arg1, arg2, arg3)
		assert(entry == nil, "expected nil entry when encoding fails")
		assert(err != nil, "expected non-nil error for unencodable dynamic argument lengths")
	}

	// Assertion 3: errors.Is matches the error returned by CorpusEntry against ErrUnencodableDynamicCorpusArgs when dynamic argument lengths are unencodable.
	{
		arg1 := make([]byte, 1)
		arg2 := make([]byte, 1)
		arg3 := make([]byte, 100000)

		_, err := ossfuzzseeds.CorpusEntry(arg1, arg2, arg3)
		assert(errors.Is(err, ossfuzzseeds.ErrUnencodableDynamicCorpusArgs),
			"errors.Is must match returned error against ErrUnencodableDynamicCorpusArgs")
	}

	// Assertion 4: The error message returned by CorpusEntry includes the sentinel error description and dynamic argument lengths.
	{
		argA := []byte("a")
		argB := []byte("b")
		argC := make([]byte, 100000)

		_, err := ossfuzzseeds.CorpusEntry(argA, argB, argC)
		assert(err != nil, "expected non-nil error")
		errMsg := err.Error()
		assert(strings.Contains(errMsg, "dynamic corpus arguments can't be encoded for OSS-Fuzz"),
			"error message must contain sentinel error string")
		assert(strings.Contains(errMsg, "lengths [1 1 100000]"),
			"error message must contain argument lengths")
	}

	// Assertion 5: CorpusEntry returns a non-empty byte slice and nil error when valid dynamic arguments are provided.
	{
		entry, err := ossfuzzseeds.CorpusEntry([]byte("hello"), "world", []byte("fuzz-seed-payload"))
		assert(err == nil, fmt.Sprintf("unexpected error for valid dynamic args: %v", err))
		assert(len(entry) > 0, "encoded corpus entry must not be empty")
		assert(!errors.Is(err, ossfuzzseeds.ErrUnencodableDynamicCorpusArgs),
			"valid arguments must not produce ErrUnencodableDynamicCorpusArgs")
	}

	fmt.Println("PASS: all github.com/quic-go/go-ossfuzz-seeds.ErrUnencodableDynamicCorpusArgs contract assertions verified")
}