1// Copyright 2011 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5//go:build ignore
6
7// Build this command explicitly: go build gotype.go
8
9/*
10The gotype command, like the front-end of a Go compiler, parses and
11type-checks a single Go package. Errors are reported if the analysis
12fails; otherwise gotype is quiet (unless -v is set).
13
14Without a list of paths, gotype reads from standard input, which
15must provide a single Go source file defining a complete package.
16
17With a single directory argument, gotype checks the Go files in
18that directory, comprising a single package. Use -t to include the
19(in-package) _test.go files. Use -x to type check only external
20test files.
21
22Otherwise, each path must be the filename of a Go file belonging
23to the same package.
24
25Imports are processed by importing directly from the source of
26imported packages (default), or by importing from compiled and
27installed packages (by setting -c to the respective compiler).
28
29The -c flag must be set to a compiler ("gc", "gccgo") when type-
30checking packages containing imports with relative import paths
31(import "./mypkg") because the source importer cannot know which
32files to include for such packages.
33
34Usage:
35
36	gotype [flags] [path...]
37
38The flags are:
39
40	-t
41		include local test files in a directory (ignored if -x is provided)
42	-x
43		consider only external test files in a directory
44	-e
45		report all errors (not just the first 10)
46	-v
47		verbose mode
48	-c
49		compiler used for installed packages (gc, gccgo, or source); default: source
50
51Flags controlling additional output:
52
53	-ast
54		print AST
55	-trace
56		print parse trace
57	-comments
58		parse comments (ignored unless -ast or -trace is provided)
59	-panic
60		panic on first error
61
62Examples:
63
64To check the files a.go, b.go, and c.go:
65
66	gotype a.go b.go c.go
67
68To check an entire package including (in-package) tests in the directory dir and print the processed files:
69
70	gotype -t -v dir
71
72To check the external test package (if any) in the current directory, based on installed packages compiled with
73cmd/compile:
74
75	gotype -c=gc -x .
76
77To verify the output of a pipe:
78
79	echo "package foo" | gotype
80*/
81package main
82
83import (
84	"flag"
85	"fmt"
86	"go/ast"
87	"go/build"
88	"go/importer"
89	"go/parser"
90	"go/scanner"
91	"go/token"
92	"go/types"
93	"io"
94	"os"
95	"path/filepath"
96	"sync"
97	"time"
98)
99
100var (
101	// main operation modes
102	testFiles  = flag.Bool("t", false, "include in-package test files in a directory")
103	xtestFiles = flag.Bool("x", false, "consider only external test files in a directory")
104	allErrors  = flag.Bool("e", false, "report all errors, not just the first 10")
105	verbose    = flag.Bool("v", false, "verbose mode")
106	compiler   = flag.String("c", "source", "compiler used for installed packages (gc, gccgo, or source)")
107
108	// additional output control
109	printAST      = flag.Bool("ast", false, "print AST")
110	printTrace    = flag.Bool("trace", false, "print parse trace")
111	parseComments = flag.Bool("comments", false, "parse comments (ignored unless -ast or -trace is provided)")
112	panicOnError  = flag.Bool("panic", false, "panic on first error")
113)
114
115var (
116	fset       = token.NewFileSet()
117	errorCount = 0
118	sequential = false
119	parserMode parser.Mode
120)
121
122func initParserMode() {
123	if *allErrors {
124		parserMode |= parser.AllErrors
125	}
126	if *printAST {
127		sequential = true
128	}
129	if *printTrace {
130		parserMode |= parser.Trace
131		sequential = true
132	}
133	if *parseComments && (*printAST || *printTrace) {
134		parserMode |= parser.ParseComments
135	}
136}
137
138const usageString = `usage: gotype [flags] [path ...]
139
140The gotype command, like the front-end of a Go compiler, parses and
141type-checks a single Go package. Errors are reported if the analysis
142fails; otherwise gotype is quiet (unless -v is set).
143
144Without a list of paths, gotype reads from standard input, which
145must provide a single Go source file defining a complete package.
146
147With a single directory argument, gotype checks the Go files in
148that directory, comprising a single package. Use -t to include the
149(in-package) _test.go files. Use -x to type check only external
150test files.
151
152Otherwise, each path must be the filename of a Go file belonging
153to the same package.
154
155Imports are processed by importing directly from the source of
156imported packages (default), or by importing from compiled and
157installed packages (by setting -c to the respective compiler).
158
159The -c flag must be set to a compiler ("gc", "gccgo") when type-
160checking packages containing imports with relative import paths
161(import "./mypkg") because the source importer cannot know which
162files to include for such packages.
163`
164
165func usage() {
166	fmt.Fprintln(os.Stderr, usageString)
167	flag.PrintDefaults()
168	os.Exit(2)
169}
170
171func report(err error) {
172	if *panicOnError {
173		panic(err)
174	}
175	scanner.PrintError(os.Stderr, err)
176	if list, ok := err.(scanner.ErrorList); ok {
177		errorCount += len(list)
178		return
179	}
180	errorCount++
181}
182
183// parse may be called concurrently.
184func parse(filename string, src any) (*ast.File, error) {
185	if *verbose {
186		fmt.Println(filename)
187	}
188	file, err := parser.ParseFile(fset, filename, src, parserMode) // ok to access fset concurrently
189	if *printAST {
190		ast.Print(fset, file)
191	}
192	return file, err
193}
194
195func parseStdin() (*ast.File, error) {
196	src, err := io.ReadAll(os.Stdin)
197	if err != nil {
198		return nil, err
199	}
200	return parse("<standard input>", src)
201}
202
203func parseFiles(dir string, filenames []string) ([]*ast.File, error) {
204	files := make([]*ast.File, len(filenames))
205	errors := make([]error, len(filenames))
206
207	var wg sync.WaitGroup
208	for i, filename := range filenames {
209		wg.Add(1)
210		go func(i int, filepath string) {
211			defer wg.Done()
212			files[i], errors[i] = parse(filepath, nil)
213		}(i, filepath.Join(dir, filename))
214		if sequential {
215			wg.Wait()
216		}
217	}
218	wg.Wait()
219
220	// If there are errors, return the first one for deterministic results.
221	var first error
222	for _, err := range errors {
223		if err != nil {
224			first = err
225			// If we have an error, some files may be nil.
226			// Remove them. (The go/parser always returns
227			// a possibly partial AST even in the presence
228			// of errors, except if the file doesn't exist
229			// in the first place, in which case it cannot
230			// matter.)
231			i := 0
232			for _, f := range files {
233				if f != nil {
234					files[i] = f
235					i++
236				}
237			}
238			files = files[:i]
239			break
240		}
241	}
242
243	return files, first
244}
245
246func parseDir(dir string) ([]*ast.File, error) {
247	ctxt := build.Default
248	pkginfo, err := ctxt.ImportDir(dir, 0)
249	if _, nogo := err.(*build.NoGoError); err != nil && !nogo {
250		return nil, err
251	}
252
253	if *xtestFiles {
254		return parseFiles(dir, pkginfo.XTestGoFiles)
255	}
256
257	filenames := append(pkginfo.GoFiles, pkginfo.CgoFiles...)
258	if *testFiles {
259		filenames = append(filenames, pkginfo.TestGoFiles...)
260	}
261	return parseFiles(dir, filenames)
262}
263
264func getPkgFiles(args []string) ([]*ast.File, error) {
265	if len(args) == 0 {
266		// stdin
267		file, err := parseStdin()
268		if err != nil {
269			return nil, err
270		}
271		return []*ast.File{file}, nil
272	}
273
274	if len(args) == 1 {
275		// possibly a directory
276		path := args[0]
277		info, err := os.Stat(path)
278		if err != nil {
279			return nil, err
280		}
281		if info.IsDir() {
282			return parseDir(path)
283		}
284	}
285
286	// list of files
287	return parseFiles("", args)
288}
289
290func checkPkgFiles(files []*ast.File) {
291	type bailout struct{}
292
293	// if checkPkgFiles is called multiple times, set up conf only once
294	conf := types.Config{
295		FakeImportC: true,
296		Error: func(err error) {
297			if !*allErrors && errorCount >= 10 {
298				panic(bailout{})
299			}
300			report(err)
301		},
302		Importer: importer.ForCompiler(fset, *compiler, nil),
303		Sizes:    types.SizesFor(build.Default.Compiler, build.Default.GOARCH),
304	}
305
306	defer func() {
307		switch p := recover().(type) {
308		case nil, bailout:
309			// normal return or early exit
310		default:
311			// re-panic
312			panic(p)
313		}
314	}()
315
316	const path = "pkg" // any non-empty string will do for now
317	conf.Check(path, fset, files, nil)
318}
319
320func printStats(d time.Duration) {
321	fileCount := 0
322	lineCount := 0
323	fset.Iterate(func(f *token.File) bool {
324		fileCount++
325		lineCount += f.LineCount()
326		return true
327	})
328
329	fmt.Printf(
330		"%s (%d files, %d lines, %d lines/s)\n",
331		d, fileCount, lineCount, int64(float64(lineCount)/d.Seconds()),
332	)
333}
334
335func main() {
336	flag.Usage = usage
337	flag.Parse()
338	initParserMode()
339
340	start := time.Now()
341
342	files, err := getPkgFiles(flag.Args())
343	if err != nil {
344		report(err)
345		// ok to continue (files may be empty, but not nil)
346	}
347
348	checkPkgFiles(files)
349	if errorCount > 0 {
350		os.Exit(2)
351	}
352
353	if *verbose {
354		printStats(time.Since(start))
355	}
356}
357