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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build ignore
// Build this command explicitly: go build gotype.go
/*
The gotype command, like the front-end of a Go compiler, parses and
type-checks a single Go package. Errors are reported if the analysis
fails; otherwise gotype is quiet (unless -v is set).
Without a list of paths, gotype reads from standard input, which
must provide a single Go source file defining a complete package.
With a single directory argument, gotype checks the Go files in
that directory, comprising a single package. Use -t to include the
(in-package) _test.go files. Use -x to type check only external
test files.
Otherwise, each path must be the filename of a Go file belonging
to the same package.
Imports are processed by importing directly from the source of
imported packages (default), or by importing from compiled and
installed packages (by setting -c to the respective compiler).
The -c flag must be set to a compiler ("gc", "gccgo") when type-
checking packages containing imports with relative import paths
(import "./mypkg") because the source importer cannot know which
files to include for such packages.
Usage:
gotype [flags] [path...]
The flags are:
-t
include local test files in a directory (ignored if -x is provided)
-x
consider only external test files in a directory
-e
report all errors (not just the first 10)
-v
verbose mode
-c
compiler used for installed packages (gc, gccgo, or source); default: source
Flags controlling additional output:
-ast
print AST
-trace
print parse trace
-comments
parse comments (ignored unless -ast or -trace is provided)
-panic
panic on first error
Examples:
To check the files a.go, b.go, and c.go:
gotype a.go b.go c.go
To check an entire package including (in-package) tests in the directory dir and print the processed files:
gotype -t -v dir
To check the external test package (if any) in the current directory, based on installed packages compiled with
cmd/compile:
gotype -c=gc -x .
To verify the output of a pipe:
echo "package foo" | gotype
*/
package main
import (
"flag"
"fmt"
"go/ast"
"go/build"
"go/importer"
"go/parser"
"go/scanner"
"go/token"
"go/types"
"io"
"os"
"path/filepath"
"sync"
"time"
)
var (
// main operation modes
testFiles = flag.Bool("t", false, "include in-package test files in a directory")
xtestFiles = flag.Bool("x", false, "consider only external test files in a directory")
allErrors = flag.Bool("e", false, "report all errors, not just the first 10")
verbose = flag.Bool("v", false, "verbose mode")
compiler = flag.String("c", "source", "compiler used for installed packages (gc, gccgo, or source)")
// additional output control
printAST = flag.Bool("ast", false, "print AST")
printTrace = flag.Bool("trace", false, "print parse trace")
parseComments = flag.Bool("comments", false, "parse comments (ignored unless -ast or -trace is provided)")
panicOnError = flag.Bool("panic", false, "panic on first error")
)
var (
fset = token.NewFileSet()
errorCount = 0
sequential = false
parserMode parser.Mode
)
func initParserMode() {
if *allErrors {
parserMode |= parser.AllErrors
}
if *printAST {
sequential = true
}
if *printTrace {
parserMode |= parser.Trace
sequential = true
}
if *parseComments && (*printAST || *printTrace) {
parserMode |= parser.ParseComments
}
}
const usageString = `usage: gotype [flags] [path ...]
The gotype command, like the front-end of a Go compiler, parses and
type-checks a single Go package. Errors are reported if the analysis
fails; otherwise gotype is quiet (unless -v is set).
Without a list of paths, gotype reads from standard input, which
must provide a single Go source file defining a complete package.
With a single directory argument, gotype checks the Go files in
that directory, comprising a single package. Use -t to include the
(in-package) _test.go files. Use -x to type check only external
test files.
Otherwise, each path must be the filename of a Go file belonging
to the same package.
Imports are processed by importing directly from the source of
imported packages (default), or by importing from compiled and
installed packages (by setting -c to the respective compiler).
The -c flag must be set to a compiler ("gc", "gccgo") when type-
checking packages containing imports with relative import paths
(import "./mypkg") because the source importer cannot know which
files to include for such packages.
`
func usage() {
fmt.Fprintln(os.Stderr, usageString)
flag.PrintDefaults()
os.Exit(2)
}
func report(err error) {
if *panicOnError {
panic(err)
}
scanner.PrintError(os.Stderr, err)
if list, ok := err.(scanner.ErrorList); ok {
errorCount += len(list)
return
}
errorCount++
}
// parse may be called concurrently
func parse(filename string, src any) (*ast.File, error) {
if *verbose {
fmt.Println(filename)
}
file, err := parser.ParseFile(fset, filename, src, parserMode) // ok to access fset concurrently
if *printAST {
ast.Print(fset, file)
}
return file, err
}
func parseStdin() (*ast.File, error) {
src, err := io.ReadAll(os.Stdin)
if err != nil {
return nil, err
}
return parse("<standard input>", src)
}
func parseFiles(dir string, filenames []string) ([]*ast.File, error) {
files := make([]*ast.File, len(filenames))
errors := make([]error, len(filenames))
var wg sync.WaitGroup
for i, filename := range filenames {
wg.Add(1)
go func(i int, filepath string) {
defer wg.Done()
files[i], errors[i] = parse(filepath, nil)
}(i, filepath.Join(dir, filename))
if sequential {
wg.Wait()
}
}
wg.Wait()
// If there are errors, return the first one for deterministic results.
var first error
for _, err := range errors {
if err != nil {
first = err
// If we have an error, some files may be nil.
// Remove them. (The go/parser always returns
// a possibly partial AST even in the presence
// of errors, except if the file doesn't exist
// in the first place, in which case it cannot
// matter.)
i := 0
for _, f := range files {
if f != nil {
files[i] = f
i++
}
}
files = files[:i]
break
}
}
return files, first
}
func parseDir(dir string) ([]*ast.File, error) {
ctxt := build.Default
pkginfo, err := ctxt.ImportDir(dir, 0)
if _, nogo := err.(*build.NoGoError); err != nil && !nogo {
return nil, err
}
if *xtestFiles {
return parseFiles(dir, pkginfo.XTestGoFiles)
}
filenames := append(pkginfo.GoFiles, pkginfo.CgoFiles...)
if *testFiles {
filenames = append(filenames, pkginfo.TestGoFiles...)
}
return parseFiles(dir, filenames)
}
func getPkgFiles(args []string) ([]*ast.File, error) {
if len(args) == 0 {
// stdin
file, err := parseStdin()
if err != nil {
return nil, err
}
return []*ast.File{file}, nil
}
if len(args) == 1 {
// possibly a directory
path := args[0]
info, err := os.Stat(path)
if err != nil {
return nil, err
}
if info.IsDir() {
return parseDir(path)
}
}
// list of files
return parseFiles("", args)
}
func checkPkgFiles(files []*ast.File) {
type bailout struct{}
// if checkPkgFiles is called multiple times, set up conf only once
conf := types.Config{
FakeImportC: true,
Error: func(err error) {
if !*allErrors && errorCount >= 10 {
panic(bailout{})
}
report(err)
},
Importer: importer.ForCompiler(fset, *compiler, nil),
Sizes: types.SizesFor(build.Default.Compiler, build.Default.GOARCH),
}
defer func() {
switch p := recover().(type) {
case nil, bailout:
// normal return or early exit
default:
// re-panic
panic(p)
}
}()
const path = "pkg" // any non-empty string will do for now
conf.Check(path, fset, files, nil)
}
func printStats(d time.Duration) {
fileCount := 0
lineCount := 0
fset.Iterate(func(f *token.File) bool {
fileCount++
lineCount += f.LineCount()
return true
})
fmt.Printf(
"%s (%d files, %d lines, %d lines/s)\n",
d, fileCount, lineCount, int64(float64(lineCount)/d.Seconds()),
)
}
func main() {
flag.Usage = usage
flag.Parse()
initParserMode()
start := time.Now()
files, err := getPkgFiles(flag.Args())
if err != nil {
report(err)
// ok to continue (files may be empty, but not nil)
}
checkPkgFiles(files)
if errorCount > 0 {
os.Exit(2)
}
if *verbose {
printStats(time.Since(start))
}
}