golang.org/x/tools v0.31.0: 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 golang.org/x/tools/go/ast/astutil.DeleteImport 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/astutil.DeleteImport

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:d925a402a45c544928c3b304650480c0274d93484b49c49eb8244b49e3426d06","contract":["astutil.DeleteImport removes an existing un-named import from AST and returns true","astutil.DeleteImport returns false when the specified import path is not present in the AST","astutil.DeleteImport removes the entire import declaration when the only import specification is deleted","astutil.DeleteImport does not delete a named import with the same import path","astutil.DeleteImport removes only the un-named import when both un-named and named imports exist for the same path"],"goal":"verify golang.org/x/tools/go/ast/astutil.DeleteImport 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/astutil.DeleteImport"]},"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/astutil.DeleteImport"],"verifierAdapter":"golang@1"}

module sample-astutil-deleteimport

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 (
	"bytes"
	"fmt"
	"go/format"
	"go/parser"
	"go/token"

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

func main() {
	src := `package main

import (
	"fmt"
	"strings"
)

func main() {
	strings.Clone("hello")
}
`
	fset := token.NewFileSet()
	file, err := parser.ParseFile(fset, "example.go", src, parser.ParseComments)
	if err != nil {
		panic(err)
	}

	// Delete unreferenced import "fmt" from the AST
	deleted := astutil.DeleteImport(fset, file, "fmt")
	fmt.Printf("Import deleted: %v\n", deleted)

	var buf bytes.Buffer
	if err := format.Node(&buf, fset, file); err != nil {
		panic(err)
	}

	fmt.Println("Resulting code:")
	fmt.Println(buf.String())
}

{
  "schemaVersion": 1,
  "goal": "verify golang.org/x/tools/go/ast/astutil.DeleteImport 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/astutil.DeleteImport"
  ]
}

package main

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

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

func main() {
	// Assertion 1: astutil.DeleteImport removes an existing un-named import from AST and returns true
	{
		src := `package main

import (
	"fmt"
	"strings"
)

func main() {
	strings.Clone("test")
}
`
		fset := token.NewFileSet()
		file, err := parser.ParseFile(fset, "example.go", src, parser.ParseComments)
		if err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: parser.ParseFile failed: %v\n", err)
			os.Exit(1)
		}

		deleted := astutil.DeleteImport(fset, file, "fmt")
		if !deleted {
			fmt.Fprintf(os.Stderr, "FAIL: DeleteImport returned false for existing import 'fmt'\n")
			os.Exit(1)
		}

		for _, imp := range file.Imports {
			if imp.Path.Value == `"fmt"` {
				fmt.Fprintf(os.Stderr, "FAIL: 'fmt' still found in file.Imports\n")
				os.Exit(1)
			}
		}

		var buf bytes.Buffer
		if err := format.Node(&buf, fset, file); err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: format.Node failed: %v\n", err)
			os.Exit(1)
		}

		formatted := buf.String()
		if strings.Contains(formatted, `"fmt"`) {
			fmt.Fprintf(os.Stderr, "FAIL: formatted code still contains 'fmt':\n%s\n", formatted)
			os.Exit(1)
		}
		if !strings.Contains(formatted, `"strings"`) {
			fmt.Fprintf(os.Stderr, "FAIL: formatted code missing 'strings':\n%s\n", formatted)
			os.Exit(1)
		}
	}

	// Assertion 2: astutil.DeleteImport returns false when the specified import path is not present in the AST
	{
		src := `package main

import "os"

func main() {
	os.Exit(0)
}
`
		fset := token.NewFileSet()
		file, err := parser.ParseFile(fset, "example.go", src, 0)
		if err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: ParseFile failed: %v\n", err)
			os.Exit(1)
		}

		deleted := astutil.DeleteImport(fset, file, "net/http")
		if deleted {
			fmt.Fprintf(os.Stderr, "FAIL: DeleteImport returned true for non-existent import 'net/http'\n")
			os.Exit(1)
		}
	}

	// Assertion 3: astutil.DeleteImport removes the entire import declaration when the only import specification is deleted
	{
		src := `package main

import "os"

func main() {}
`
		fset := token.NewFileSet()
		file, err := parser.ParseFile(fset, "example.go", src, 0)
		if err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: ParseFile failed: %v\n", err)
			os.Exit(1)
		}

		deleted := astutil.DeleteImport(fset, file, "os")
		if !deleted {
			fmt.Fprintf(os.Stderr, "FAIL: DeleteImport returned false for single import 'os'\n")
			os.Exit(1)
		}

		if len(file.Imports) != 0 {
			fmt.Fprintf(os.Stderr, "FAIL: expected 0 imports, got %d\n", len(file.Imports))
			os.Exit(1)
		}

		for _, decl := range file.Decls {
			if genDecl, ok := decl.(*ast.GenDecl); ok && genDecl.Tok == token.IMPORT {
				fmt.Fprintf(os.Stderr, "FAIL: import GenDecl was not removed from file.Decls\n")
				os.Exit(1)
			}
		}
	}

	// Assertion 4: astutil.DeleteImport does not delete a named import with the same import path
	{
		src := `package main

import myfmt "fmt"

func main() {
	myfmt.Println("hello")
}
`
		fset := token.NewFileSet()
		file, err := parser.ParseFile(fset, "example.go", src, 0)
		if err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: ParseFile failed: %v\n", err)
			os.Exit(1)
		}

		deleted := astutil.DeleteImport(fset, file, "fmt")
		if deleted {
			fmt.Fprintf(os.Stderr, "FAIL: DeleteImport deleted named import 'myfmt \"fmt\"'\n")
			os.Exit(1)
		}

		if len(file.Imports) != 1 || file.Imports[0].Name.Name != "myfmt" {
			fmt.Fprintf(os.Stderr, "FAIL: named import modified unexpectedly\n")
			os.Exit(1)
		}
	}

	// Assertion 5: astutil.DeleteImport removes only the un-named import when both un-named and named imports exist for the same path
	{
		src := `package main

import (
	"fmt"
	customfmt "fmt"
)

func main() {
	customfmt.Println("hello")
}
`
		fset := token.NewFileSet()
		file, err := parser.ParseFile(fset, "example.go", src, 0)
		if err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: ParseFile failed: %v\n", err)
			os.Exit(1)
		}

		deleted := astutil.DeleteImport(fset, file, "fmt")
		if !deleted {
			fmt.Fprintf(os.Stderr, "FAIL: DeleteImport failed when named and un-named import coexist\n")
			os.Exit(1)
		}

		if len(file.Imports) != 1 {
			fmt.Fprintf(os.Stderr, "FAIL: expected 1 remaining import, got %d\n", len(file.Imports))
			os.Exit(1)
		}

		if file.Imports[0].Name == nil || file.Imports[0].Name.Name != "customfmt" {
			fmt.Fprintf(os.Stderr, "FAIL: remaining import is not 'customfmt': %v\n", file.Imports[0])
			os.Exit(1)
		}
	}

	fmt.Println("PASS: astutil.DeleteImport contract passed")
}