golang.org/x/tools v0.31.0: inspector.New

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 golang.org/x/tools/go/ast/inspector.New in pkg:golang/golang.org/x/tools@v0.31.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/tools@v0.31.0
Demonstrate these symbols/APIs:
  - golang.org/x/tools/go/ast/inspector.New

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:aa863151077c6e9ad1ce7bab096702781cdbd168723bca8ac8f2cc9bf654bdcb","contract":["inspector.New constructs an Inspector from Go AST files for filtered AST traversal","inspector.Preorder visits specified AST node types in preorder traversal","inspector.Nodes walks AST nodes with push and pop notifications for matching node types","inspector.WithStack provides parent AST node hierarchy in stack during traversal"],"goal":"verify golang.org/x/tools/go/ast/inspector.New in pkg:golang/golang.org/x/tools@v0.31.0","kind":"HOW","packages":["pkg:golang/golang.org/x/tools@v0.31.0"],"schemaVersion":1,"symbols":["golang.org/x/tools/go/ast/inspector.New"]},"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@v0.31.0"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/tools@v0.31.0","symbols":["golang.org/x/tools/go/ast/inspector.New"],"verifierAdapter":"golang@1"}

module example.com/inspectortest

go 1.23.0

require golang.org/x/tools v0.31.0

golang.org/x/tools v0.31.0 h1:0EedkvKDbh+qistFTd0Bcwe/YLh4vHwWEkiI0toFIBU=
golang.org/x/tools v0.31.0/go.mod h1:naFTU+Cev749tSJRXJlna0T3WxKvb1kWEx15xA4SdmQ=

package main

import (
	"fmt"
	"go/ast"
	"go/parser"
	"go/token"
	"log"

	"golang.org/x/tools/go/ast/inspector"
)

func main() {
	src := `package sample

func greet() {
	println("hello")
}

func farewell() {
	println("goodbye")
}
`
	fset := token.NewFileSet()
	file, err := parser.ParseFile(fset, "sample.go", src, 0)
	if err != nil {
		log.Fatalf("ParseFile failed: %v", err)
	}

	insp := inspector.New([]*ast.File{file})
	fmt.Println("Functions in AST:")
	insp.Preorder([]ast.Node{&ast.FuncDecl{}}, func(n ast.Node) {
		fn := n.(*ast.FuncDecl)
		fmt.Printf("- %s\n", fn.Name.Name)
	})
}

{
  "schemaVersion": 1,
  "goal": "verify golang.org/x/tools/go/ast/inspector.New in pkg:golang/golang.org/x/tools@v0.31.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/tools@v0.31.0"
  ],
  "symbols": [
    "golang.org/x/tools/go/ast/inspector.New"
  ]
}

package main

import (
	"fmt"
	"go/ast"
	"go/parser"
	"go/token"
	"os"

	"golang.org/x/tools/go/ast/inspector"
)

func parseSnippet(src string) (*ast.File, error) {
	fset := token.NewFileSet()
	return parser.ParseFile(fset, "example.go", src, 0)
}

func main() {
	src := `package testpkg

var x = 10
var y = 20

func alpha() {
	msg := "hello"
	_ = msg
}

func beta() {
	println("world")
}
`
	file, err := parseSnippet(src)
	if err != nil {
		fmt.Fprintf(os.Stderr, "parseSnippet failed: %v\n", err)
		os.Exit(1)
	}

	// 1. inspector.New constructs an Inspector from Go AST files for filtered AST traversal.
	insp := inspector.New([]*ast.File{file})
	if insp == nil {
		fmt.Fprintf(os.Stderr, "inspector.New returned nil\n")
		os.Exit(1)
	}

	// 2. inspector.Preorder visits specified AST node types in preorder traversal.
	var funcNames []string
	insp.Preorder([]ast.Node{&ast.FuncDecl{}}, func(n ast.Node) {
		fn, ok := n.(*ast.FuncDecl)
		if ok {
			funcNames = append(funcNames, fn.Name.Name)
		}
	})
	expectedFuncs := []string{"alpha", "beta"}
	if len(funcNames) != len(expectedFuncs) {
		fmt.Fprintf(os.Stderr, "Preorder expected %d functions, got %d\n", len(expectedFuncs), len(funcNames))
		os.Exit(1)
	}
	for i, name := range expectedFuncs {
		if funcNames[i] != name {
			fmt.Fprintf(os.Stderr, "Preorder func mismatch at %d: got %s, want %s\n", i, funcNames[i], name)
			os.Exit(1)
		}
	}

	// 3. inspector.Nodes walks AST nodes with push and pop notifications for matching node types.
	var pushCount, popCount int
	insp.Nodes([]ast.Node{&ast.GenDecl{}}, func(n ast.Node, push bool) bool {
		if push {
			pushCount++
		} else {
			popCount++
		}
		return true
	})
	if pushCount != 2 || popCount != 2 {
		fmt.Fprintf(os.Stderr, "Nodes push/pop mismatch: push=%d, pop=%d, expected 2 and 2\n", pushCount, popCount)
		os.Exit(1)
	}

	// 4. inspector.WithStack provides parent AST node hierarchy in stack during traversal.
	var visitedAlphaIdent bool
	insp.WithStack([]ast.Node{&ast.Ident{}}, func(n ast.Node, push bool, stack []ast.Node) bool {
		if !push {
			return true
		}
		ident, ok := n.(*ast.Ident)
		if ok && ident.Name == "alpha" {
			visitedAlphaIdent = true
			if len(stack) == 0 {
				fmt.Fprintf(os.Stderr, "WithStack returned empty stack for ident alpha\n")
				os.Exit(1)
			}
			hasFuncDeclParent := false
			for _, parent := range stack {
				if _, ok := parent.(*ast.FuncDecl); ok {
					hasFuncDeclParent = true
					break
				}
			}
			if !hasFuncDeclParent {
				fmt.Fprintf(os.Stderr, "WithStack missing FuncDecl in stack for ident alpha\n")
				os.Exit(1)
			}
		}
		return true
	})
	if !visitedAlphaIdent {
		fmt.Fprintf(os.Stderr, "WithStack did not visit ident alpha\n")
		os.Exit(1)
	}

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