modernc.org/gc/v3 v3.1.4

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 pkg:golang/modernc.org/gc/v3@v3.1.4
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/modernc.org/gc/v3@v3.1.4

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:sha256:6d0ce9cd95772ad9060b03c026ad986ef9de82facb85506fc214ef2947679d5d","contract":["gc.ParseFile parses valid Go source code and returns an AST with non-nil SourceFile","gc.ParseFile returns an error when parsing syntactically invalid Go source code","ast.Source reconstructs the Go source code from the parsed AST","gc.NewABI creates an ABI instance for supported target OS and architecture linux amd64","gc.NewABI returns an error for invalid or unsupported OS and architecture combinations","gc.NewCache initializes an AST cache with positive capacity and returns an error for non-positive capacity"],"goal":"verify pkg:golang/modernc.org/gc/v3@v3.1.4","kind":"HOW","packages":["pkg:golang/modernc.org/gc/v3@v3.1.4"],"schemaVersion":1},"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/modernc.org/gc/v3@v3.1.4"],"schemaVersion":1,"subject":"pkg:golang/modernc.org/gc/v3@v3.1.4","verifierAdapter":"golang@1"}

module example.com/sample

go 1.26.6

require modernc.org/gc/v3 v3.1.4

require (
	github.com/dustin/go-humanize v1.0.1 // indirect
	github.com/hashicorp/golang-lru/v2 v2.0.7 // indirect
	github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec // indirect
	modernc.org/mathutil v1.7.1 // indirect
	modernc.org/strutil v1.2.1 // indirect
	modernc.org/token v1.1.0 // indirect
)

github.com/dustin/go-humanize v1.0.1 h1:GzkhY7T5VNhEkwH0PVJgjz+fX1rhBrR7pRT3mDkpeCY=
github.com/dustin/go-humanize v1.0.1/go.mod h1:Mu1zIs6XwVuF/gI1OepvI0qD18qycQx+mFykh5fBlto=
github.com/hashicorp/golang-lru/v2 v2.0.7 h1:a+bsQ5rvGLjzHuww6tVxozPZFVghXaHOwFs4luLUK2k=
github.com/hashicorp/golang-lru/v2 v2.0.7/go.mod h1:QeFd9opnmA6QUJc5vARoKUSoFhyfM2/ZepoAG6RGpeM=
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/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec h1:W09IVJc94icq4NjY3clb7Lk8O1qJ8BdBEF8z0ibU0rE=
github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec/go.mod h1:qqbHyh8v60DhA7CoWK5oRCqLrMHRGoxYCSS9EjAz6Eo=
golang.org/x/mod v0.24.0 h1:ZfthKaKaT4NrhGVZHO1/WDTwGES4De8KtWO0SIbNJMU=
golang.org/x/mod v0.24.0/go.mod h1:IXM97Txy2VM4PJ3gI61r1YEk/gAj6zAHN3AdZt6S9Ww=
golang.org/x/sync v0.12.0 h1:MHc5BpPuC30uJk597Ri8TV3CNZcTLu6B6z4lJy+g6Jw=
golang.org/x/sync v0.12.0/go.mod h1:1dzgHSNfp02xaA81J2MS99Qcpr2w7fw1gpm99rleRqA=
golang.org/x/tools v0.31.0 h1:0EedkvKDbh+qistFTd0Bcwe/YLh4vHwWEkiI0toFIBU=
golang.org/x/tools v0.31.0/go.mod h1:naFTU+Cev749tSJRXJlna0T3WxKvb1kWEx15xA4SdmQ=
modernc.org/gc/v3 v3.1.4 h1:2g65LGVSmFQrXeITAw97x7hCRvZFcyE1uDP+7Vng7JI=
modernc.org/gc/v3 v3.1.4/go.mod h1:HFK/6AGESC7Ex+EZJhJ2Gni6cTaYpSMmU/cT9RmlfYY=
modernc.org/mathutil v1.7.1 h1:GCZVGXdaN8gTqB1Mf/usp1Y/hSqgI2vAGGP4jZMCxOU=
modernc.org/mathutil v1.7.1/go.mod h1:4p5IwJITfppl0G4sUEDtCr4DthTaT47/N3aT6MhfgJg=
modernc.org/strutil v1.2.1 h1:UneZBkQA+DX2Rp35KcM69cSsNES9ly8mQWD71HKlOA0=
modernc.org/strutil v1.2.1/go.mod h1:EHkiggD70koQxjVdSBM3JKM7k6L0FbGE5eymy9i3B9A=
modernc.org/token v1.1.0 h1:Xl7Ap9dKaEs5kLoOQeQmPWevfnk/DM5qcLcYlA8ys6Y=
modernc.org/token v1.1.0/go.mod h1:UGzOrNV1mAFSEB63lOFHIpNRUVMvYTc6yu1SMY/XTDM=

package main

import (
	"fmt"
	"log"

	"modernc.org/gc/v3"
)

func main() {
	src := []byte("package sample\n\nfunc Add(a, b int) int {\n\treturn a + b\n}\n")

	ast, err := gc.ParseFile("sample.go", src)
	if err != nil {
		log.Fatalf("ParseFile failed: %v", err)
	}

	pkgName := ast.SourceFile.PackageClause.PackageName.Src()
	fmt.Printf("Parsed Go package: %s\n", pkgName)
	fmt.Printf("Reconstructed source:\n%s\n", ast.Source(false))

	abi, err := gc.NewABI("linux", "amd64")
	if err != nil {
		log.Fatalf("NewABI failed: %v", err)
	}
	fmt.Printf("Target ABI ByteOrder: %v\n", abi.ByteOrder)
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:golang/modernc.org/gc/v3@v3.1.4",
  "kind": "HOW",
  "packages": [
    "pkg:golang/modernc.org/gc/v3@v3.1.4"
  ]
}

package main

import (
	"fmt"
	"os"
	"strings"

	"modernc.org/gc/v3"
)

func main() {
	// Assertion 1: gc.ParseFile parses valid Go source code and returns an AST with non-nil SourceFile
	{
		src := []byte("package sample\n\nfunc Add(a, b int) int { return a + b }\n")
		ast, err := gc.ParseFile("sample.go", src)
		if err != nil {
			fmt.Fprintf(os.Stderr, "Assertion 1 failed: unexpected error: %v\n", err)
			os.Exit(1)
		}
		if ast == nil || ast.SourceFile == nil {
			fmt.Fprintf(os.Stderr, "Assertion 1 failed: AST or SourceFile is nil\n")
			os.Exit(1)
		}
		pkgName := ast.SourceFile.PackageClause.PackageName.Src()
		if pkgName != "sample" {
			fmt.Fprintf(os.Stderr, "Assertion 1 failed: expected package name 'sample', got %q\n", pkgName)
			os.Exit(1)
		}
	}

	// Assertion 2: gc.ParseFile returns an error when parsing syntactically invalid Go source code
	{
		invalidSrc := []byte("package ;;; invalid syntax")
		_, err := gc.ParseFile("invalid.go", invalidSrc)
		if err == nil {
			fmt.Fprintf(os.Stderr, "Assertion 2 failed: expected error for invalid Go source, got nil\n")
			os.Exit(1)
		}
	}

	// Assertion 3: ast.Source reconstructs the Go source code from the parsed AST
	{
		src := []byte("package sample\n\nfunc Add(a, b int) int { return a + b }\n")
		ast, err := gc.ParseFile("sample.go", src)
		if err != nil {
			fmt.Fprintf(os.Stderr, "Assertion 3 failed: parse error: %v\n", err)
			os.Exit(1)
		}
		rendered := ast.Source(false)
		if !strings.Contains(rendered, "package sample") || !strings.Contains(rendered, "func Add") {
			fmt.Fprintf(os.Stderr, "Assertion 3 failed: rendered source missing expected tokens: %q\n", rendered)
			os.Exit(1)
		}
	}

	// Assertion 4: gc.NewABI creates an ABI instance for supported target OS and architecture linux amd64
	{
		abi, err := gc.NewABI("linux", "amd64")
		if err != nil {
			fmt.Fprintf(os.Stderr, "Assertion 4 failed: unexpected error: %v\n", err)
			os.Exit(1)
		}
		if abi == nil {
			fmt.Fprintf(os.Stderr, "Assertion 4 failed: expected non-nil ABI\n")
			os.Exit(1)
		}
	}

	// Assertion 5: gc.NewABI returns an error for invalid or unsupported OS and architecture combinations
	{
		_, err := gc.NewABI("invalid_os", "invalid_arch")
		if err == nil {
			fmt.Fprintf(os.Stderr, "Assertion 5 failed: expected error for invalid os/arch, got nil\n")
			os.Exit(1)
		}
	}

	// Assertion 6: gc.NewCache initializes an AST cache with positive capacity and returns an error for non-positive capacity
	{
		cache, err := gc.NewCache(64)
		if err != nil {
			fmt.Fprintf(os.Stderr, "Assertion 6 failed: unexpected error creating cache: %v\n", err)
			os.Exit(1)
		}
		if cache == nil {
			fmt.Fprintf(os.Stderr, "Assertion 6 failed: expected non-nil cache\n")
			os.Exit(1)
		}

		_, errZero := gc.NewCache(0)
		if errZero == nil {
			fmt.Fprintf(os.Stderr, "Assertion 6 failed: expected error for cache size 0, got nil\n")
			os.Exit(1)
		}
	}

	fmt.Println("All contract assertions passed.")
}