modernc.org/gc/v3 v3.1.4: ParseFile

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 modernc.org/gc/v3.ParseFile in 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
Demonstrate these symbols/APIs:
  - modernc.org/gc/v3.ParseFile

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:sha256:462639f4076f365083648c012ea6ccb61ffd8c10aa04ecb09932a7224e4513ba","contract":["gc.ParseFile parses valid Go source code and returns a non-nil AST with nil error","gc.ParseFile extracts the package clause and package name from valid Go source","gc.ParseFile returns a syntax error when parsing invalid Go source code","gc.ParseFile returns a syntax error when parsing empty byte slice input"],"goal":"verify modernc.org/gc/v3.ParseFile in pkg:golang/modernc.org/gc/v3@v3.1.4","kind":"HOW","packages":["pkg:golang/modernc.org/gc/v3@v3.1.4"],"schemaVersion":1,"symbols":["modernc.org/gc/v3.ParseFile"]},"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","symbols":["modernc.org/gc/v3.ParseFile"],"verifierAdapter":"golang@1"}

module 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"

	"modernc.org/gc/v3"
)

func main() {
	src := []byte("package main\n\nfunc main() {}\n")
	ast, err := gc.ParseFile("main.go", src)
	if err != nil {
		fmt.Printf("ParseFile error: %v\n", err)
		return
	}
	fmt.Printf("Parsed package: %s\n", ast.SourceFile.PackageClause.PackageName.Src())
}

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

package main

import (
	"fmt"
	"os"

	"modernc.org/gc/v3"
)

func main() {
	// Assertion 1: gc.ParseFile parses valid Go source code and returns a non-nil AST with nil error
	{
		src := []byte("package calc\n\nfunc Add(a, b int) int {\n\treturn a + b\n}\n")
		ast, err := gc.ParseFile("calc.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: expected non-nil AST and SourceFile\n")
			os.Exit(1)
		}
	}

	// Assertion 2: gc.ParseFile extracts the package clause and package name from valid Go source
	{
		src := []byte("package samplepkg\n\nvar X = 1\n")
		ast, err := gc.ParseFile("samplepkg.go", src)
		if err != nil {
			fmt.Fprintf(os.Stderr, "Assertion 2 failed: unexpected error: %v\n", err)
			os.Exit(1)
		}
		if ast.SourceFile.PackageClause == nil {
			fmt.Fprintf(os.Stderr, "Assertion 2 failed: expected non-nil PackageClause\n")
			os.Exit(1)
		}
		pkgName := ast.SourceFile.PackageClause.PackageName.Src()
		if pkgName != "samplepkg" {
			fmt.Fprintf(os.Stderr, "Assertion 2 failed: expected package name %q, got %q\n", "samplepkg", pkgName)
			os.Exit(1)
		}
	}

	// Assertion 3: gc.ParseFile returns a syntax error when parsing invalid Go source code
	{
		src := []byte("package main\n\nfunc broken() {")
		ast, err := gc.ParseFile("broken.go", src)
		if err == nil {
			fmt.Fprintf(os.Stderr, "Assertion 3 failed: expected syntax error, got nil\n")
			os.Exit(1)
		}
		if ast != nil {
			fmt.Fprintf(os.Stderr, "Assertion 3 failed: expected nil AST on syntax error, got %v\n", ast)
			os.Exit(1)
		}
	}

	// Assertion 4: gc.ParseFile returns a syntax error when parsing empty byte slice input
	{
		src := []byte("")
		ast, err := gc.ParseFile("empty.go", src)
		if err == nil {
			fmt.Fprintf(os.Stderr, "Assertion 4 failed: expected syntax error for empty source, got nil\n")
			os.Exit(1)
		}
		if ast != nil {
			fmt.Fprintf(os.Stderr, "Assertion 4 failed: expected nil AST on empty source, got %v\n", ast)
			os.Exit(1)
		}
	}

	fmt.Println("PASS: all ParseFile contract assertions passed")
}