golang.org/x/tools v0.45.0: astutil.AddImport, astutil.Apply, astutil.DeleteImport

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/golang.org/x/tools@v0.45.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/tools@v0.45.0

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:sha256:495cbe67b6111a09dc3779fbb4da00838fe2a9ac2ce33dc8f7d306d9e3c92c03","contract":["txtar.Parse extracts archive comment and file entries from raw txtar bytes","txtar.Format serializes a txtar.Archive back to identical raw txtar bytes","astutil.AddImport adds a new import path to a parsed *ast.File and returns false when already present","astutil.UsesImport reports whether an imported package identifier is referenced in the AST","astutil.DeleteImport removes an unreferenced import declaration from a parsed *ast.File","astutil.Apply traverses an AST and replaces matching nodes via Cursor.Replace"],"goal":"verify pkg:golang/golang.org/x/tools@v0.45.0","kind":"HOW","packages":["pkg:golang/golang.org/x/tools@v0.45.0"],"schemaVersion":1,"symbols":["astutil.AddImport","astutil.Apply","astutil.DeleteImport","astutil.UsesImport","txtar.Format","txtar.Parse"]},"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/golang.org/x/tools@v0.45.0"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/tools@v0.45.0","symbols":["astutil.AddImport","astutil.Apply","astutil.DeleteImport","astutil.UsesImport","txtar.Format","txtar.Parse"],"verifierAdapter":"golang@1"}

module sample

go 1.25.0

require golang.org/x/tools v0.45.0

golang.org/x/tools v0.45.0 h1:18qN3FAooORvApf5XjCXgsuayZOEtXf6JK18I3+ONa8=
golang.org/x/tools v0.45.0/go.mod h1:LuUGqqaXcXMEFEruIVJVm5mgDD8vww/z/SR1gQ4uE/0=

{
  "schemaVersion": 1,
  "goal": "verify pkg:golang/golang.org/x/tools@v0.45.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/tools@v0.45.0"
  ]
}

package main

import (
	"bytes"
	"fmt"
	"go/ast"
	"go/format"
	"go/parser"
	"go/token"
	"os"
	"strings"

	"golang.org/x/tools/go/ast/astutil"
	"golang.org/x/tools/txtar"
)

func assert(cond bool, msg string) {
	if !cond {
		fmt.Fprintln(os.Stderr, "assertion failed:", msg)
		os.Exit(1)
	}
}

func main() {
	// 1. Verify txtar.Parse and txtar.Format round-trip archive handling.
	rawArchive := []byte("top comment line\n-- alpha.txt --\nhello alpha\n-- dir/beta.go --\npackage beta\n")
	arc := txtar.Parse(rawArchive)
	assert(strings.TrimSpace(string(arc.Comment)) == "top comment line", "txtar.Parse should extract archive comment")
	assert(len(arc.Files) == 2, "txtar.Parse should extract two files")
	assert(arc.Files[0].Name == "alpha.txt" && string(arc.Files[0].Data) == "hello alpha\n", "first file name and content should match")
	assert(arc.Files[1].Name == "dir/beta.go" && string(arc.Files[1].Data) == "package beta\n", "second file name and content should match")

	formatted := txtar.Format(arc)
	assert(bytes.Equal(formatted, rawArchive), "txtar.Format should round-trip parsed archive identically")

	// 2. Verify astutil.AddImport, astutil.UsesImport, and astutil.DeleteImport on parsed Go AST.
	fset := token.NewFileSet()
	src := "package p\n\nfunc Greet() string {\n\treturn fmt.Sprintf(\"hi\")\n}\n"
	file, err := parser.ParseFile(fset, "p.go", src, parser.ParseComments)
	assert(err == nil, "parser.ParseFile should succeed")

	added := astutil.AddImport(fset, file, "fmt")
	assert(added, "astutil.AddImport should return true when adding new import")
	addedAgain := astutil.AddImport(fset, file, "fmt")
	assert(!addedAgain, "astutil.AddImport should return false when import already exists")
	assert(astutil.UsesImport(file, "fmt"), "astutil.UsesImport should report true when package identifier is referenced")

	addedUnused := astutil.AddImport(fset, file, "strings")
	assert(addedUnused, "astutil.AddImport should add strings import")
	assert(!astutil.UsesImport(file, "strings"), "astutil.UsesImport should report false for unused import")
	deleted := astutil.DeleteImport(fset, file, "strings")
	assert(deleted, "astutil.DeleteImport should remove existing import")

	// 3. Verify astutil.Apply for AST node replacement.
	rewritten := astutil.Apply(file, func(c *astutil.Cursor) bool {
		if lit, ok := c.Node().(*ast.BasicLit); ok && lit.Kind == token.STRING && lit.Value == `"hi"` {
			c.Replace(&ast.BasicLit{
				Kind:  token.STRING,
				Value: `"hello"`,
			})
		}
		return true
	}, nil)
	rewrittenFile, ok := rewritten.(*ast.File)
	assert(ok, "astutil.Apply should return *ast.File")

	var out bytes.Buffer
	err = format.Node(&out, fset, rewrittenFile)
	assert(err == nil, "format.Node should succeed")
	rendered := out.String()
	assert(strings.Contains(rendered, `"fmt"`), "rendered AST should include fmt import")
	assert(!strings.Contains(rendered, `"strings"`), "rendered AST should not include deleted strings import")
	assert(strings.Contains(rendered, `"hello"`), "rendered AST should contain replaced string literal")
}