/
main.go
494 lines (446 loc) · 13.1 KB
/
main.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
// Copyright 2010 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.
// Vet is a simple checker for static errors in Go source code.
// See doc.go for more information.
package main
import (
"bytes"
"flag"
"fmt"
"go/ast"
"go/build"
"go/parser"
"go/printer"
"go/token"
"io/ioutil"
"os"
"path/filepath"
"strconv"
"strings"
"code.google.com/p/go.tools/go/exact"
_ "code.google.com/p/go.tools/go/gcimporter"
"code.google.com/p/go.tools/go/types"
)
var verbose = flag.Bool("v", false, "verbose")
var strictShadowing = flag.Bool("shadowstrict", false, "whether to be strict about shadowing; can be noisy")
var testFlag = flag.Bool("test", false, "for testing only: sets -all and -shadow")
var exitCode = 0
// Flags to control which checks to perform. "all" is set to true here, and disabled later if
// a flag is set explicitly.
var report = map[string]*bool{
"all": flag.Bool("all", true, "check everything; disabled if any explicit check is requested"),
"asmdecl": flag.Bool("asmdecl", false, "check assembly against Go declarations"),
"assign": flag.Bool("assign", false, "check for useless assignments"),
"atomic": flag.Bool("atomic", false, "check for common mistaken usages of the sync/atomic package"),
"buildtags": flag.Bool("buildtags", false, "check that +build tags are valid"),
"composites": flag.Bool("composites", false, "check that composite literals used field-keyed elements"),
"copylocks": flag.Bool("copylocks", false, "check that locks are not passed by value"),
"methods": flag.Bool("methods", false, "check that canonically named methods are canonically defined"),
"nilfunc": flag.Bool("nilfunc", false, "check for comparisons between functions and nil"),
"printf": flag.Bool("printf", false, "check printf-like invocations"),
"rangeloops": flag.Bool("rangeloops", false, "check that range loop variables are used correctly"),
"shadow": flag.Bool("shadow", false, "check for shadowed variables (experimental; must be set explicitly)"),
"structtags": flag.Bool("structtags", false, "check that struct field tags have canonical format"),
"unreachable": flag.Bool("unreachable", false, "check for unreachable code"),
}
// TODO: Need a flag to set build tags when parsing the package.
// vet tells whether to report errors for the named check, a flag name.
func vet(name string) bool {
if *testFlag {
return true
}
if name == "shadow" {
return *report["shadow"]
}
return *report["all"] || *report[name]
}
// setExit sets the value for os.Exit when it is called, later. It
// remembers the highest value.
func setExit(err int) {
if err > exitCode {
exitCode = err
}
}
// Usage is a replacement usage function for the flags package.
func Usage() {
fmt.Fprintf(os.Stderr, "Usage of %s:\n", os.Args[0])
fmt.Fprintf(os.Stderr, "\tvet [flags] directory...\n")
fmt.Fprintf(os.Stderr, "\tvet [flags] files... # Must be a single package\n")
flag.PrintDefaults()
os.Exit(2)
}
// File is a wrapper for the state of a file used in the parser.
// The parse tree walkers are all methods of this type.
type File struct {
pkg *Package
fset *token.FileSet
name string
content []byte
file *ast.File
b bytes.Buffer // for use by methods
// The last "String() string" method receiver we saw while walking.
// This is used by the recursiveStringer method in print.go.
lastStringerReceiver *ast.Object
}
func main() {
flag.Usage = Usage
flag.Parse()
// If a check is named explicitly, turn off the 'all' flag.
for name, ptr := range report {
if name != "all" && *ptr {
*report["all"] = false
break
}
}
if *printfuncs != "" {
for _, name := range strings.Split(*printfuncs, ",") {
if len(name) == 0 {
flag.Usage()
}
skip := 0
if colon := strings.LastIndex(name, ":"); colon > 0 {
var err error
skip, err = strconv.Atoi(name[colon+1:])
if err != nil {
errorf(`illegal format for "Func:N" argument %q; %s`, name, err)
}
name = name[:colon]
}
name = strings.ToLower(name)
if name[len(name)-1] == 'f' {
printfList[name] = skip
} else {
printList[name] = skip
}
}
}
if flag.NArg() == 0 {
Usage()
}
dirs := false
files := false
for _, name := range flag.Args() {
// Is it a directory?
fi, err := os.Stat(name)
if err != nil {
warnf("error walking tree: %s", err)
continue
}
if fi.IsDir() {
dirs = true
} else {
files = true
}
}
if dirs && files {
Usage()
}
if dirs {
for _, name := range flag.Args() {
walkDir(name)
}
return
}
if !doPackage(".", flag.Args()) {
warnf("no files checked")
}
os.Exit(exitCode)
}
// prefixDirectory places the directory name on the beginning of each name in the list.
func prefixDirectory(directory string, names []string) {
if directory != "." {
for i, name := range names {
names[i] = filepath.Join(directory, name)
}
}
}
// doPackageDir analyzes the single package found in the directory, if there is one,
// plus a test package, if there is one.
func doPackageDir(directory string) {
pkg, err := build.Default.ImportDir(directory, 0)
if err != nil {
// If it's just that there are no go source files, that's fine.
if _, nogo := err.(*build.NoGoError); nogo {
return
}
// Non-fatal: we are doing a recursive walk and there may be other directories.
warnf("cannot process directory %s: %s", directory, err)
return
}
var names []string
names = append(names, pkg.GoFiles...)
names = append(names, pkg.CgoFiles...)
names = append(names, pkg.TestGoFiles...) // These are also in the "foo" package.
names = append(names, pkg.SFiles...)
prefixDirectory(directory, names)
doPackage(directory, names)
// Is there also a "foo_test" package? If so, do that one as well.
if len(pkg.XTestGoFiles) > 0 {
names = pkg.XTestGoFiles
prefixDirectory(directory, names)
doPackage(directory, names)
}
}
type Package struct {
path string
idents map[*ast.Ident]types.Object
types map[ast.Expr]types.Type
values map[ast.Expr]exact.Value
spans map[types.Object]Span
files []*File
typesPkg *types.Package
}
// doPackage analyzes the single package constructed from the named files.
// It returns whether any files were checked.
func doPackage(directory string, names []string) bool {
var files []*File
var astFiles []*ast.File
fs := token.NewFileSet()
for _, name := range names {
f, err := os.Open(name)
if err != nil {
// Warn but continue to next package.
warnf("%s: %s", name, err)
return false
}
defer f.Close()
data, err := ioutil.ReadAll(f)
if err != nil {
warnf("%s: %s", name, err)
return false
}
checkBuildTag(name, data)
var parsedFile *ast.File
if strings.HasSuffix(name, ".go") {
parsedFile, err = parser.ParseFile(fs, name, bytes.NewReader(data), 0)
if err != nil {
warnf("%s: %s", name, err)
return false
}
astFiles = append(astFiles, parsedFile)
}
files = append(files, &File{fset: fs, content: data, name: name, file: parsedFile})
}
if len(astFiles) == 0 {
return false
}
pkg := new(Package)
pkg.path = astFiles[0].Name.Name
pkg.files = files
// Type check the package.
err := pkg.check(fs, astFiles)
if err != nil && *verbose {
warnf("%s", err)
}
for _, file := range files {
file.pkg = pkg
if file.file != nil {
file.walkFile(file.name, file.file)
}
}
asmCheck(pkg)
return true
}
func visit(path string, f os.FileInfo, err error) error {
if err != nil {
warnf("walk error: %s", err)
return err
}
// One package per directory. Ignore the files themselves.
if !f.IsDir() {
return nil
}
doPackageDir(path)
return nil
}
func (pkg *Package) hasFileWithSuffix(suffix string) bool {
for _, f := range pkg.files {
if strings.HasSuffix(f.name, suffix) {
return true
}
}
return false
}
// walkDir recursively walks the tree looking for Go packages.
func walkDir(root string) {
filepath.Walk(root, visit)
}
// errorf formats the error to standard error, adding program
// identification and a newline, and exits.
func errorf(format string, args ...interface{}) {
fmt.Fprintf(os.Stderr, "vet: "+format+"\n", args...)
os.Exit(2)
}
// warnf formats the error to standard error, adding program
// identification and a newline, but does not exit.
func warnf(format string, args ...interface{}) {
fmt.Fprintf(os.Stderr, "vet: "+format+"\n", args...)
setExit(1)
}
// Println is fmt.Println guarded by -v.
func Println(args ...interface{}) {
if !*verbose {
return
}
fmt.Println(args...)
}
// Printf is fmt.Printf guarded by -v.
func Printf(format string, args ...interface{}) {
if !*verbose {
return
}
fmt.Printf(format+"\n", args...)
}
// Bad reports an error and sets the exit code..
func (f *File) Bad(pos token.Pos, args ...interface{}) {
f.Warn(pos, args...)
setExit(1)
}
// Badf reports a formatted error and sets the exit code.
func (f *File) Badf(pos token.Pos, format string, args ...interface{}) {
f.Warnf(pos, format, args...)
setExit(1)
}
// loc returns a formatted representation of the position.
func (f *File) loc(pos token.Pos) string {
if pos == token.NoPos {
return ""
}
// Do not print columns. Because the pos often points to the start of an
// expression instead of the inner part with the actual error, the
// precision can mislead.
posn := f.fset.Position(pos)
return fmt.Sprintf("%s:%d", posn.Filename, posn.Line)
}
// Warn reports an error but does not set the exit code.
func (f *File) Warn(pos token.Pos, args ...interface{}) {
fmt.Fprint(os.Stderr, f.loc(pos)+": "+fmt.Sprintln(args...))
}
// Warnf reports a formatted error but does not set the exit code.
func (f *File) Warnf(pos token.Pos, format string, args ...interface{}) {
fmt.Fprintf(os.Stderr, f.loc(pos)+": "+format+"\n", args...)
}
// walkFile walks the file's tree.
func (f *File) walkFile(name string, file *ast.File) {
Println("Checking file", name)
ast.Walk(f, file)
}
// Visit implements the ast.Visitor interface.
func (f *File) Visit(node ast.Node) ast.Visitor {
switch n := node.(type) {
case *ast.AssignStmt:
f.walkAssignStmt(n)
case *ast.BinaryExpr:
f.walkBinaryExpr(n)
case *ast.CallExpr:
f.walkCallExpr(n)
case *ast.CompositeLit:
f.walkCompositeLit(n)
case *ast.Field:
f.walkFieldTag(n)
case *ast.FuncDecl:
f.walkFuncDecl(n)
case *ast.FuncLit:
f.walkFuncLit(n)
case *ast.GenDecl:
f.walkGenDecl(n)
case *ast.InterfaceType:
f.walkInterfaceType(n)
case *ast.RangeStmt:
f.walkRangeStmt(n)
}
return f
}
// walkAssignStmt walks an assignment statement
func (f *File) walkAssignStmt(stmt *ast.AssignStmt) {
f.checkAssignStmt(stmt)
f.checkAtomicAssignment(stmt)
f.checkShadowAssignment(stmt)
}
func (f *File) walkBinaryExpr(expr *ast.BinaryExpr) {
f.checkNilFuncComparison(expr)
}
// walkCall walks a call expression.
func (f *File) walkCall(call *ast.CallExpr, name string) {
f.checkFmtPrintfCall(call, name)
}
// walkCallExpr walks a call expression.
func (f *File) walkCallExpr(call *ast.CallExpr) {
switch x := call.Fun.(type) {
case *ast.Ident:
f.walkCall(call, x.Name)
case *ast.SelectorExpr:
f.walkCall(call, x.Sel.Name)
}
}
// walkCompositeLit walks a composite literal.
func (f *File) walkCompositeLit(c *ast.CompositeLit) {
f.checkUnkeyedLiteral(c)
}
// walkFieldTag walks a struct field tag.
func (f *File) walkFieldTag(field *ast.Field) {
if field.Tag == nil {
return
}
f.checkCanonicalFieldTag(field)
}
// walkMethod walks the method's signature.
func (f *File) walkMethod(id *ast.Ident, t *ast.FuncType) {
f.checkCanonicalMethod(id, t)
}
// walkFuncDecl walks a function declaration.
func (f *File) walkFuncDecl(d *ast.FuncDecl) {
f.checkUnreachable(d.Body)
if d.Recv != nil {
f.walkMethod(d.Name, d.Type)
}
f.prepStringerReceiver(d)
f.checkCopyLocks(d)
}
// prepStringerReceiver checks whether the given declaration is a fmt.Stringer
// implementation, and if so sets the File's lastStringerReceiver field to the
// declaration's receiver object.
func (f *File) prepStringerReceiver(d *ast.FuncDecl) {
if !f.isStringer(d) {
return
}
if l := d.Recv.List; len(l) == 1 {
if n := l[0].Names; len(n) == 1 {
f.lastStringerReceiver = n[0].Obj
}
}
}
// isStringer returns true if the provided declaration is a "String() string"
// method; an implementation of fmt.Stringer.
func (f *File) isStringer(d *ast.FuncDecl) bool {
return d.Recv != nil && d.Name.Name == "String" &&
len(d.Type.Params.List) == 0 && len(d.Type.Results.List) == 1 &&
f.pkg.types[d.Type.Results.List[0].Type] == types.Typ[types.String]
}
// walkGenDecl walks a general declaration.
func (f *File) walkGenDecl(d *ast.GenDecl) {
f.checkShadowDecl(d)
}
// walkFuncLit walks a function literal.
func (f *File) walkFuncLit(x *ast.FuncLit) {
f.checkUnreachable(x.Body)
}
// walkInterfaceType walks the method signatures of an interface.
func (f *File) walkInterfaceType(t *ast.InterfaceType) {
for _, field := range t.Methods.List {
for _, id := range field.Names {
f.walkMethod(id, field.Type.(*ast.FuncType))
}
}
}
// walkRangeStmt walks a range statement.
func (f *File) walkRangeStmt(n *ast.RangeStmt) {
checkRangeLoop(f, n)
}
// gofmt returns a string representation of the expression.
func (f *File) gofmt(x ast.Expr) string {
f.b.Reset()
printer.Fprint(&f.b, f.fset, x)
return f.b.String()
}