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
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
|
// Copyright (c) 2013 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 or at
// https://developers.google.com/open-source/licenses/bsd.
// Package lint contains a linter for Go source code.
package lint // import "golang.org/x/lint"
import (
"bufio"
"bytes"
"fmt"
"go/ast"
"go/parser"
"go/printer"
"go/token"
"go/types"
"regexp"
"sort"
"strconv"
"strings"
"unicode"
"unicode/utf8"
"golang.org/x/tools/go/ast/astutil"
"golang.org/x/tools/go/gcexportdata"
)
const styleGuideBase = "https://golang.org/wiki/CodeReviewComments"
// A Linter lints Go source code.
type Linter struct {
}
// Problem represents a problem in some source code.
type Problem struct {
Position token.Position // position in source file
Text string // the prose that describes the problem
Link string // (optional) the link to the style guide for the problem
Confidence float64 // a value in (0,1] estimating the confidence in this problem's correctness
LineText string // the source line
Category string // a short name for the general category of the problem
// If the problem has a suggested fix (the minority case),
// ReplacementLine is a full replacement for the relevant line of the source file.
ReplacementLine string
}
func (p *Problem) String() string {
if p.Link != "" {
return p.Text + "\n\n" + p.Link
}
return p.Text
}
type byPosition []Problem
func (p byPosition) Len() int { return len(p) }
func (p byPosition) Swap(i, j int) { p[i], p[j] = p[j], p[i] }
func (p byPosition) Less(i, j int) bool {
pi, pj := p[i].Position, p[j].Position
if pi.Filename != pj.Filename {
return pi.Filename < pj.Filename
}
if pi.Line != pj.Line {
return pi.Line < pj.Line
}
if pi.Column != pj.Column {
return pi.Column < pj.Column
}
return p[i].Text < p[j].Text
}
// Lint lints src.
func (l *Linter) Lint(filename string, src []byte) ([]Problem, error) {
return l.LintFiles(map[string][]byte{filename: src})
}
// LintFiles lints a set of files of a single package.
// The argument is a map of filename to source.
func (l *Linter) LintFiles(files map[string][]byte) ([]Problem, error) {
pkg := &pkg{
fset: token.NewFileSet(),
files: make(map[string]*file),
}
var pkgName string
for filename, src := range files {
if isGenerated(src) {
continue // See issue #239
}
f, err := parser.ParseFile(pkg.fset, filename, src, parser.ParseComments)
if err != nil {
return nil, err
}
if pkgName == "" {
pkgName = f.Name.Name
} else if f.Name.Name != pkgName {
return nil, fmt.Errorf("%s is in package %s, not %s", filename, f.Name.Name, pkgName)
}
pkg.files[filename] = &file{
pkg: pkg,
f: f,
fset: pkg.fset,
src: src,
filename: filename,
}
}
if len(pkg.files) == 0 {
return nil, nil
}
return pkg.lint(), nil
}
var (
genHdr = []byte("// Code generated ")
genFtr = []byte(" DO NOT EDIT.")
)
// isGenerated reports whether the source file is generated code
// according the rules from https://golang.org/s/generatedcode.
func isGenerated(src []byte) bool {
sc := bufio.NewScanner(bytes.NewReader(src))
for sc.Scan() {
b := sc.Bytes()
if bytes.HasPrefix(b, genHdr) && bytes.HasSuffix(b, genFtr) && len(b) >= len(genHdr)+len(genFtr) {
return true
}
}
return false
}
// pkg represents a package being linted.
type pkg struct {
fset *token.FileSet
files map[string]*file
typesPkg *types.Package
typesInfo *types.Info
// sortable is the set of types in the package that implement sort.Interface.
sortable map[string]bool
// main is whether this is a "main" package.
main bool
problems []Problem
}
func (p *pkg) lint() []Problem {
if err := p.typeCheck(); err != nil {
/* TODO(dsymonds): Consider reporting these errors when golint operates on entire packages.
if e, ok := err.(types.Error); ok {
pos := p.fset.Position(e.Pos)
conf := 1.0
if strings.Contains(e.Msg, "can't find import: ") {
// Golint is probably being run in a context that doesn't support
// typechecking (e.g. package files aren't found), so don't warn about it.
conf = 0
}
if conf > 0 {
p.errorfAt(pos, conf, category("typechecking"), e.Msg)
}
// TODO(dsymonds): Abort if !e.Soft?
}
*/
}
p.scanSortable()
p.main = p.isMain()
for _, f := range p.files {
f.lint()
}
sort.Sort(byPosition(p.problems))
return p.problems
}
// file represents a file being linted.
type file struct {
pkg *pkg
f *ast.File
fset *token.FileSet
src []byte
filename string
}
func (f *file) isTest() bool { return strings.HasSuffix(f.filename, "_test.go") }
func (f *file) lint() {
f.lintPackageComment()
f.lintImports()
f.lintBlankImports()
f.lintExported()
f.lintNames()
f.lintVarDecls()
f.lintElses()
f.lintRanges()
f.lintErrorf()
f.lintErrors()
f.lintErrorStrings()
f.lintReceiverNames()
f.lintIncDec()
f.lintErrorReturn()
f.lintUnexportedReturn()
f.lintTimeNames()
f.lintContextKeyTypes()
f.lintContextArgs()
}
type link string
type category string
// The variadic arguments may start with link and category types,
// and must end with a format string and any arguments.
// It returns the new Problem.
func (f *file) errorf(n ast.Node, confidence float64, args ...interface{}) *Problem {
pos := f.fset.Position(n.Pos())
if pos.Filename == "" {
pos.Filename = f.filename
}
return f.pkg.errorfAt(pos, confidence, args...)
}
func (p *pkg) errorfAt(pos token.Position, confidence float64, args ...interface{}) *Problem {
problem := Problem{
Position: pos,
Confidence: confidence,
}
if pos.Filename != "" {
// The file might not exist in our mapping if a //line directive was encountered.
if f, ok := p.files[pos.Filename]; ok {
problem.LineText = srcLine(f.src, pos)
}
}
argLoop:
for len(args) > 1 { // always leave at least the format string in args
switch v := args[0].(type) {
case link:
problem.Link = string(v)
case category:
problem.Category = string(v)
default:
break argLoop
}
args = args[1:]
}
problem.Text = fmt.Sprintf(args[0].(string), args[1:]...)
p.problems = append(p.problems, problem)
return &p.problems[len(p.problems)-1]
}
var newImporter = func(fset *token.FileSet) types.ImporterFrom {
return gcexportdata.NewImporter(fset, make(map[string]*types.Package))
}
func (p *pkg) typeCheck() error {
config := &types.Config{
// By setting a no-op error reporter, the type checker does as much work as possible.
Error: func(error) {},
Importer: newImporter(p.fset),
}
info := &types.Info{
Types: make(map[ast.Expr]types.TypeAndValue),
Defs: make(map[*ast.Ident]types.Object),
Uses: make(map[*ast.Ident]types.Object),
Scopes: make(map[ast.Node]*types.Scope),
}
var anyFile *file
var astFiles []*ast.File
for _, f := range p.files {
anyFile = f
astFiles = append(astFiles, f.f)
}
pkg, err := config.Check(anyFile.f.Name.Name, p.fset, astFiles, info)
// Remember the typechecking info, even if config.Check failed,
// since we will get partial information.
p.typesPkg = pkg
p.typesInfo = info
return err
}
func (p *pkg) typeOf(expr ast.Expr) types.Type {
if p.typesInfo == nil {
return nil
}
return p.typesInfo.TypeOf(expr)
}
func (p *pkg) isNamedType(typ types.Type, importPath, name string) bool {
n, ok := typ.(*types.Named)
if !ok {
return false
}
tn := n.Obj()
return tn != nil && tn.Pkg() != nil && tn.Pkg().Path() == importPath && tn.Name() == name
}
// scopeOf returns the tightest scope encompassing id.
func (p *pkg) scopeOf(id *ast.Ident) *types.Scope {
var scope *types.Scope
if obj := p.typesInfo.ObjectOf(id); obj != nil {
scope = obj.Parent()
}
if scope == p.typesPkg.Scope() {
// We were given a top-level identifier.
// Use the file-level scope instead of the package-level scope.
pos := id.Pos()
for _, f := range p.files {
if f.f.Pos() <= pos && pos < f.f.End() {
scope = p.typesInfo.Scopes[f.f]
break
}
}
}
return scope
}
func (p *pkg) scanSortable() {
p.sortable = make(map[string]bool)
// bitfield for which methods exist on each type.
const (
Len = 1 << iota
Less
Swap
)
nmap := map[string]int{"Len": Len, "Less": Less, "Swap": Swap}
has := make(map[string]int)
for _, f := range p.files {
f.walk(func(n ast.Node) bool {
fn, ok := n.(*ast.FuncDecl)
if !ok || fn.Recv == nil || len(fn.Recv.List) == 0 {
return true
}
// TODO(dsymonds): We could check the signature to be more precise.
recv := receiverType(fn)
if i, ok := nmap[fn.Name.Name]; ok {
has[recv] |= i
}
return false
})
}
for typ, ms := range has {
if ms == Len|Less|Swap {
p.sortable[typ] = true
}
}
}
func (p *pkg) isMain() bool {
for _, f := range p.files {
if f.isMain() {
return true
}
}
return false
}
func (f *file) isMain() bool {
if f.f.Name.Name == "main" {
return true
}
return false
}
// lintPackageComment checks package comments. It complains if
// there is no package comment, or if it is not of the right form.
// This has a notable false positive in that a package comment
// could rightfully appear in a different file of the same package,
// but that's not easy to fix since this linter is file-oriented.
func (f *file) lintPackageComment() {
if f.isTest() {
return
}
const ref = styleGuideBase + "#package-comments"
prefix := "Package " + f.f.Name.Name + " "
// Look for a detached package comment.
// First, scan for the last comment that occurs before the "package" keyword.
var lastCG *ast.CommentGroup
for _, cg := range f.f.Comments {
if cg.Pos() > f.f.Package {
// Gone past "package" keyword.
break
}
lastCG = cg
}
if lastCG != nil && strings.HasPrefix(lastCG.Text(), prefix) {
endPos := f.fset.Position(lastCG.End())
pkgPos := f.fset.Position(f.f.Package)
if endPos.Line+1 < pkgPos.Line {
// There isn't a great place to anchor this error;
// the start of the blank lines between the doc and the package statement
// is at least pointing at the location of the problem.
pos := token.Position{
Filename: endPos.Filename,
// Offset not set; it is non-trivial, and doesn't appear to be needed.
Line: endPos.Line + 1,
Column: 1,
}
f.pkg.errorfAt(pos, 0.9, link(ref), category("comments"), "package comment is detached; there should be no blank lines between it and the package statement")
return
}
}
if f.f.Doc == nil {
f.errorf(f.f, 0.2, link(ref), category("comments"), "should have a package comment, unless it's in another file for this package")
return
}
s := f.f.Doc.Text()
if ts := strings.TrimLeft(s, " \t"); ts != s {
f.errorf(f.f.Doc, 1, link(ref), category("comments"), "package comment should not have leading space")
s = ts
}
// Only non-main packages need to keep to this form.
if !f.pkg.main && !strings.HasPrefix(s, prefix) {
f.errorf(f.f.Doc, 1, link(ref), category("comments"), `package comment should be of the form "%s..."`, prefix)
}
}
// lintBlankImports complains if a non-main package has blank imports that are
// not documented.
func (f *file) lintBlankImports() {
// In package main and in tests, we don't complain about blank imports.
if f.pkg.main || f.isTest() {
return
}
// The first element of each contiguous group of blank imports should have
// an explanatory comment of some kind.
for i, imp := range f.f.Imports {
pos := f.fset.Position(imp.Pos())
if !isBlank(imp.Name) {
continue // Ignore non-blank imports.
}
if i > 0 {
prev := f.f.Imports[i-1]
prevPos := f.fset.Position(prev.Pos())
if isBlank(prev.Name) && prevPos.Line+1 == pos.Line {
continue // A subsequent blank in a group.
}
}
// This is the first blank import of a group.
if imp.Doc == nil && imp.Comment == nil {
ref := ""
f.errorf(imp, 1, link(ref), category("imports"), "a blank import should be only in a main or test package, or have a comment justifying it")
}
}
}
// lintImports examines import blocks.
func (f *file) lintImports() {
for i, is := range f.f.Imports {
_ = i
if is.Name != nil && is.Name.Name == "." && !f.isTest() {
f.errorf(is, 1, link(styleGuideBase+"#import-dot"), category("imports"), "should not use dot imports")
}
}
}
const docCommentsLink = styleGuideBase + "#doc-comments"
// lintExported examines the exported names.
// It complains if any required doc comments are missing,
// or if they are not of the right form. The exact rules are in
// lintFuncDoc, lintTypeDoc and lintValueSpecDoc; this function
// also tracks the GenDecl structure being traversed to permit
// doc comments for constants to be on top of the const block.
// It also complains if the names stutter when combined with
// the package name.
func (f *file) lintExported() {
if f.isTest() {
return
}
var lastGen *ast.GenDecl // last GenDecl entered.
// Set of GenDecls that have already had missing comments flagged.
genDeclMissingComments := make(map[*ast.GenDecl]bool)
f.walk(func(node ast.Node) bool {
switch v := node.(type) {
case *ast.GenDecl:
if v.Tok == token.IMPORT {
return false
}
// token.CONST, token.TYPE or token.VAR
lastGen = v
return true
case *ast.FuncDecl:
f.lintFuncDoc(v)
if v.Recv == nil {
// Only check for stutter on functions, not methods.
// Method names are not used package-qualified.
f.checkStutter(v.Name, "func")
}
// Don't proceed inside funcs.
return false
case *ast.TypeSpec:
// inside a GenDecl, which usually has the doc
doc := v.Doc
if doc == nil {
doc = lastGen.Doc
}
f.lintTypeDoc(v, doc)
f.checkStutter(v.Name, "type")
// Don't proceed inside types.
return false
case *ast.ValueSpec:
f.lintValueSpecDoc(v, lastGen, genDeclMissingComments)
return false
}
return true
})
}
var (
allCapsRE = regexp.MustCompile(`^[A-Z0-9_]+$`)
anyCapsRE = regexp.MustCompile(`[A-Z]`)
)
// knownNameExceptions is a set of names that are known to be exempt from naming checks.
// This is usually because they are constrained by having to match names in the
// standard library.
var knownNameExceptions = map[string]bool{
"LastInsertId": true, // must match database/sql
"kWh": true,
}
func isInTopLevel(f *ast.File, ident *ast.Ident) bool {
path, _ := astutil.PathEnclosingInterval(f, ident.Pos(), ident.End())
for _, f := range path {
switch f.(type) {
case *ast.File, *ast.GenDecl, *ast.ValueSpec, *ast.Ident:
continue
}
return false
}
return true
}
// lintNames examines all names in the file.
// It complains if any use underscores or incorrect known initialisms.
func (f *file) lintNames() {
// Package names need slightly different handling than other names.
if strings.Contains(f.f.Name.Name, "_") && !strings.HasSuffix(f.f.Name.Name, "_test") {
f.errorf(f.f, 1, link("http://golang.org/doc/effective_go.html#package-names"), category("naming"), "don't use an underscore in package name")
}
if anyCapsRE.MatchString(f.f.Name.Name) {
f.errorf(f.f, 1, link("http://golang.org/doc/effective_go.html#package-names"), category("mixed-caps"), "don't use MixedCaps in package name; %s should be %s", f.f.Name.Name, strings.ToLower(f.f.Name.Name))
}
check := func(id *ast.Ident, thing string) {
if id.Name == "_" {
return
}
if knownNameExceptions[id.Name] {
return
}
// Handle two common styles from other languages that don't belong in Go.
if len(id.Name) >= 5 && allCapsRE.MatchString(id.Name) && strings.Contains(id.Name, "_") {
capCount := 0
for _, c := range id.Name {
if 'A' <= c && c <= 'Z' {
capCount++
}
}
if capCount >= 2 {
f.errorf(id, 0.8, link(styleGuideBase+"#mixed-caps"), category("naming"), "don't use ALL_CAPS in Go names; use CamelCase")
return
}
}
if thing == "const" || (thing == "var" && isInTopLevel(f.f, id)) {
if len(id.Name) > 2 && id.Name[0] == 'k' && id.Name[1] >= 'A' && id.Name[1] <= 'Z' {
should := string(id.Name[1]+'a'-'A') + id.Name[2:]
f.errorf(id, 0.8, link(styleGuideBase+"#mixed-caps"), category("naming"), "don't use leading k in Go names; %s %s should be %s", thing, id.Name, should)
}
}
should := lintName(id.Name)
if id.Name == should {
return
}
if len(id.Name) > 2 && strings.Contains(id.Name[1:], "_") {
f.errorf(id, 0.9, link("http://golang.org/doc/effective_go.html#mixed-caps"), category("naming"), "don't use underscores in Go names; %s %s should be %s", thing, id.Name, should)
return
}
f.errorf(id, 0.8, link(styleGuideBase+"#initialisms"), category("naming"), "%s %s should be %s", thing, id.Name, should)
}
checkList := func(fl *ast.FieldList, thing string) {
if fl == nil {
return
}
for _, f := range fl.List {
for _, id := range f.Names {
check(id, thing)
}
}
}
f.walk(func(node ast.Node) bool {
switch v := node.(type) {
case *ast.AssignStmt:
if v.Tok == token.ASSIGN {
return true
}
for _, exp := range v.Lhs {
if id, ok := exp.(*ast.Ident); ok {
check(id, "var")
}
}
case *ast.FuncDecl:
if f.isTest() && (strings.HasPrefix(v.Name.Name, "Example") || strings.HasPrefix(v.Name.Name, "Test") || strings.HasPrefix(v.Name.Name, "Benchmark")) {
return true
}
thing := "func"
if v.Recv != nil {
thing = "method"
}
// Exclude naming warnings for functions that are exported to C but
// not exported in the Go API.
// See https://github.com/golang/lint/issues/144.
if ast.IsExported(v.Name.Name) || !isCgoExported(v) {
check(v.Name, thing)
}
checkList(v.Type.Params, thing+" parameter")
checkList(v.Type.Results, thing+" result")
case *ast.GenDecl:
if v.Tok == token.IMPORT {
return true
}
var thing string
switch v.Tok {
case token.CONST:
thing = "const"
case token.TYPE:
thing = "type"
case token.VAR:
thing = "var"
}
for _, spec := range v.Specs {
switch s := spec.(type) {
case *ast.TypeSpec:
check(s.Name, thing)
case *ast.ValueSpec:
for _, id := range s.Names {
check(id, thing)
}
}
}
case *ast.InterfaceType:
// Do not check interface method names.
// They are often constrainted by the method names of concrete types.
for _, x := range v.Methods.List {
ft, ok := x.Type.(*ast.FuncType)
if !ok { // might be an embedded interface name
continue
}
checkList(ft.Params, "interface method parameter")
checkList(ft.Results, "interface method result")
}
case *ast.RangeStmt:
if v.Tok == token.ASSIGN {
return true
}
if id, ok := v.Key.(*ast.Ident); ok {
check(id, "range var")
}
if id, ok := v.Value.(*ast.Ident); ok {
check(id, "range var")
}
case *ast.StructType:
for _, f := range v.Fields.List {
for _, id := range f.Names {
check(id, "struct field")
}
}
}
return true
})
}
// lintName returns a different name if it should be different.
func lintName(name string) (should string) {
// Fast path for simple cases: "_" and all lowercase.
if name == "_" {
return name
}
allLower := true
for _, r := range name {
if !unicode.IsLower(r) {
allLower = false
break
}
}
if allLower {
return name
}
// Split camelCase at any lower->upper transition, and split on underscores.
// Check each word for common initialisms.
runes := []rune(name)
w, i := 0, 0 // index of start of word, scan
for i+1 <= len(runes) {
eow := false // whether we hit the end of a word
if i+1 == len(runes) {
eow = true
} else if runes[i+1] == '_' {
// underscore; shift the remainder forward over any run of underscores
eow = true
n := 1
for i+n+1 < len(runes) && runes[i+n+1] == '_' {
n++
}
// Leave at most one underscore if the underscore is between two digits
if i+n+1 < len(runes) && unicode.IsDigit(runes[i]) && unicode.IsDigit(runes[i+n+1]) {
n--
}
copy(runes[i+1:], runes[i+n+1:])
runes = runes[:len(runes)-n]
} else if unicode.IsLower(runes[i]) && !unicode.IsLower(runes[i+1]) {
// lower->non-lower
eow = true
}
i++
if !eow {
continue
}
// [w,i) is a word.
word := string(runes[w:i])
if u := strings.ToUpper(word); commonInitialisms[u] {
// Keep consistent case, which is lowercase only at the start.
if w == 0 && unicode.IsLower(runes[w]) {
u = strings.ToLower(u)
}
// All the common initialisms are ASCII,
// so we can replace the bytes exactly.
copy(runes[w:], []rune(u))
} else if w > 0 && strings.ToLower(word) == word {
// already all lowercase, and not the first word, so uppercase the first character.
runes[w] = unicode.ToUpper(runes[w])
}
w = i
}
return string(runes)
}
// commonInitialisms is a set of common initialisms.
// Only add entries that are highly unlikely to be non-initialisms.
// For instance, "ID" is fine (Freudian code is rare), but "AND" is not.
var commonInitialisms = map[string]bool{
"ACL": true,
"API": true,
"ASCII": true,
"CPU": true,
"CSS": true,
"DNS": true,
"EOF": true,
"GUID": true,
"HTML": true,
"HTTP": true,
"HTTPS": true,
"ID": true,
"IP": true,
"JSON": true,
"LHS": true,
"QPS": true,
"RAM": true,
"RHS": true,
"RPC": true,
"SLA": true,
"SMTP": true,
"SQL": true,
"SSH": true,
"TCP": true,
"TLS": true,
"TTL": true,
"UDP": true,
"UI": true,
"UID": true,
"UUID": true,
"URI": true,
"URL": true,
"UTF8": true,
"VM": true,
"XML": true,
"XMPP": true,
"XSRF": true,
"XSS": true,
}
// lintTypeDoc examines the doc comment on a type.
// It complains if they are missing from an exported type,
// or if they are not of the standard form.
func (f *file) lintTypeDoc(t *ast.TypeSpec, doc *ast.CommentGroup) {
if !ast.IsExported(t.Name.Name) {
return
}
if doc == nil {
f.errorf(t, 1, link(docCommentsLink), category("comments"), "exported type %v should have comment or be unexported", t.Name)
return
}
s := doc.Text()
articles := [...]string{"A", "An", "The"}
for _, a := range articles {
if strings.HasPrefix(s, a+" ") {
s = s[len(a)+1:]
break
}
}
if !strings.HasPrefix(s, t.Name.Name+" ") {
f.errorf(doc, 1, link(docCommentsLink), category("comments"), `comment on exported type %v should be of the form "%v ..." (with optional leading article)`, t.Name, t.Name)
}
}
var commonMethods = map[string]bool{
"Error": true,
"Read": true,
"ServeHTTP": true,
"String": true,
"Write": true,
}
// lintFuncDoc examines doc comments on functions and methods.
// It complains if they are missing, or not of the right form.
// It has specific exclusions for well-known methods (see commonMethods above).
func (f *file) lintFuncDoc(fn *ast.FuncDecl) {
if !ast.IsExported(fn.Name.Name) {
// func is unexported
return
}
kind := "function"
name := fn.Name.Name
if fn.Recv != nil && len(fn.Recv.List) > 0 {
// method
kind = "method"
recv := receiverType(fn)
if !ast.IsExported(recv) {
// receiver is unexported
return
}
if commonMethods[name] {
return
}
switch name {
case "Len", "Less", "Swap":
if f.pkg.sortable[recv] {
return
}
}
name = recv + "." + name
}
if fn.Doc == nil {
f.errorf(fn, 1, link(docCommentsLink), category("comments"), "exported %s %s should have comment or be unexported", kind, name)
return
}
s := fn.Doc.Text()
prefix := fn.Name.Name + " "
if !strings.HasPrefix(s, prefix) {
f.errorf(fn.Doc, 1, link(docCommentsLink), category("comments"), `comment on exported %s %s should be of the form "%s..."`, kind, name, prefix)
}
}
// lintValueSpecDoc examines package-global variables and constants.
// It complains if they are not individually declared,
// or if they are not suitably documented in the right form (unless they are in a block that is commented).
func (f *file) lintValueSpecDoc(vs *ast.ValueSpec, gd *ast.GenDecl, genDeclMissingComments map[*ast.GenDecl]bool) {
kind := "var"
if gd.Tok == token.CONST {
kind = "const"
}
if len(vs.Names) > 1 {
// Check that none are exported except for the first.
for _, n := range vs.Names[1:] {
if ast.IsExported(n.Name) {
f.errorf(vs, 1, category("comments"), "exported %s %s should have its own declaration", kind, n.Name)
return
}
}
}
// Only one name.
name := vs.Names[0].Name
if !ast.IsExported(name) {
return
}
if vs.Doc == nil && gd.Doc == nil {
if genDeclMissingComments[gd] {
return
}
block := ""
if kind == "const" && gd.Lparen.IsValid() {
block = " (or a comment on this block)"
}
f.errorf(vs, 1, link(docCommentsLink), category("comments"), "exported %s %s should have comment%s or be unexported", kind, name, block)
genDeclMissingComments[gd] = true
return
}
// If this GenDecl has parens and a comment, we don't check its comment form.
if gd.Lparen.IsValid() && gd.Doc != nil {
return
}
// The relevant text to check will be on either vs.Doc or gd.Doc.
// Use vs.Doc preferentially.
doc := vs.Doc
if doc == nil {
doc = gd.Doc
}
prefix := name + " "
if !strings.HasPrefix(doc.Text(), prefix) {
f.errorf(doc, 1, link(docCommentsLink), category("comments"), `comment on exported %s %s should be of the form "%s..."`, kind, name, prefix)
}
}
func (f *file) checkStutter(id *ast.Ident, thing string) {
pkg, name := f.f.Name.Name, id.Name
if !ast.IsExported(name) {
// unexported name
return
}
// A name stutters if the package name is a strict prefix
// and the next character of the name starts a new word.
if len(name) <= len(pkg) {
// name is too short to stutter.
// This permits the name to be the same as the package name.
return
}
if !strings.EqualFold(pkg, name[:len(pkg)]) {
return
}
// We can assume the name is well-formed UTF-8.
// If the next rune after the package name is uppercase or an underscore
// the it's starting a new word and thus this name stutters.
rem := name[len(pkg):]
if next, _ := utf8.DecodeRuneInString(rem); next == '_' || unicode.IsUpper(next) {
f.errorf(id, 0.8, link(styleGuideBase+"#package-names"), category("naming"), "%s name will be used as %s.%s by other packages, and that stutters; consider calling this %s", thing, pkg, name, rem)
}
}
// zeroLiteral is a set of ast.BasicLit values that are zero values.
// It is not exhaustive.
var zeroLiteral = map[string]bool{
"false": true, // bool
// runes
`'\x00'`: true,
`'\000'`: true,
// strings
`""`: true,
"``": true,
// numerics
"0": true,
"0.": true,
"0.0": true,
"0i": true,
}
// lintVarDecls examines variable declarations. It complains about declarations with
// redundant LHS types that can be inferred from the RHS.
func (f *file) lintVarDecls() {
var lastGen *ast.GenDecl // last GenDecl entered.
f.walk(func(node ast.Node) bool {
switch v := node.(type) {
case *ast.GenDecl:
if v.Tok != token.CONST && v.Tok != token.VAR {
return false
}
lastGen = v
return true
case *ast.ValueSpec:
if lastGen.Tok == token.CONST {
return false
}
if len(v.Names) > 1 || v.Type == nil || len(v.Values) == 0 {
return false
}
rhs := v.Values[0]
// An underscore var appears in a common idiom for compile-time interface satisfaction,
// as in "var _ Interface = (*Concrete)(nil)".
if isIdent(v.Names[0], "_") {
return false
}
// If the RHS is a zero value, suggest dropping it.
zero := false
if lit, ok := rhs.(*ast.BasicLit); ok {
zero = zeroLiteral[lit.Value]
} else if isIdent(rhs, "nil") {
zero = true
}
if zero {
f.errorf(rhs, 0.9, category("zero-value"), "should drop = %s from declaration of var %s; it is the zero value", f.render(rhs), v.Names[0])
return false
}
lhsTyp := f.pkg.typeOf(v.Type)
rhsTyp := f.pkg.typeOf(rhs)
if !validType(lhsTyp) || !validType(rhsTyp) {
// Type checking failed (often due to missing imports).
return false
}
if !types.Identical(lhsTyp, rhsTyp) {
// Assignment to a different type is not redundant.
return false
}
// The next three conditions are for suppressing the warning in situations
// where we were unable to typecheck.
// If the LHS type is an interface, don't warn, since it is probably a
// concrete type on the RHS. Note that our feeble lexical check here
// will only pick up interface{} and other literal interface types;
// that covers most of the cases we care to exclude right now.
if _, ok := v.Type.(*ast.InterfaceType); ok {
return false
}
// If the RHS is an untyped const, only warn if the LHS type is its default type.
if defType, ok := f.isUntypedConst(rhs); ok && !isIdent(v.Type, defType) {
return false
}
f.errorf(v.Type, 0.8, category("type-inference"), "should omit type %s from declaration of var %s; it will be inferred from the right-hand side", f.render(v.Type), v.Names[0])
return false
}
return true
})
}
func validType(T types.Type) bool {
return T != nil &&
T != types.Typ[types.Invalid] &&
!strings.Contains(T.String(), "invalid type") // good but not foolproof
}
// lintElses examines else blocks. It complains about any else block whose if block ends in a return.
func (f *file) lintElses() {
// We don't want to flag if { } else if { } else { } constructions.
// They will appear as an IfStmt whose Else field is also an IfStmt.
// Record such a node so we ignore it when we visit it.
ignore := make(map[*ast.IfStmt]bool)
f.walk(func(node ast.Node) bool {
ifStmt, ok := node.(*ast.IfStmt)
if !ok || ifStmt.Else == nil {
return true
}
if elseif, ok := ifStmt.Else.(*ast.IfStmt); ok {
ignore[elseif] = true
return true
}
if ignore[ifStmt] {
return true
}
if _, ok := ifStmt.Else.(*ast.BlockStmt); !ok {
// only care about elses without conditions
return true
}
if len(ifStmt.Body.List) == 0 {
return true
}
shortDecl := false // does the if statement have a ":=" initialization statement?
if ifStmt.Init != nil {
if as, ok := ifStmt.Init.(*ast.AssignStmt); ok && as.Tok == token.DEFINE {
shortDecl = true
}
}
lastStmt := ifStmt.Body.List[len(ifStmt.Body.List)-1]
if _, ok := lastStmt.(*ast.ReturnStmt); ok {
extra := ""
if shortDecl {
extra = " (move short variable declaration to its own line if necessary)"
}
f.errorf(ifStmt.Else, 1, link(styleGuideBase+"#indent-error-flow"), category("indent"), "if block ends with a return statement, so drop this else and outdent its block"+extra)
}
return true
})
}
// lintRanges examines range clauses. It complains about redundant constructions.
func (f *file) lintRanges() {
f.walk(func(node ast.Node) bool {
rs, ok := node.(*ast.RangeStmt)
if !ok {
return true
}
if isIdent(rs.Key, "_") && (rs.Value == nil || isIdent(rs.Value, "_")) {
p := f.errorf(rs.Key, 1, category("range-loop"), "should omit values from range; this loop is equivalent to `for range ...`")
newRS := *rs // shallow copy
newRS.Value = nil
newRS.Key = nil
p.ReplacementLine = f.firstLineOf(&newRS, rs)
return true
}
if isIdent(rs.Value, "_") {
p := f.errorf(rs.Value, 1, category("range-loop"), "should omit 2nd value from range; this loop is equivalent to `for %s %s range ...`", f.render(rs.Key), rs.Tok)
newRS := *rs // shallow copy
newRS.Value = nil
p.ReplacementLine = f.firstLineOf(&newRS, rs)
}
return true
})
}
// lintErrorf examines errors.New and testing.Error calls. It complains if its only argument is an fmt.Sprintf invocation.
func (f *file) lintErrorf() {
f.walk(func(node ast.Node) bool {
ce, ok := node.(*ast.CallExpr)
if !ok || len(ce.Args) != 1 {
return true
}
isErrorsNew := isPkgDot(ce.Fun, "errors", "New")
var isTestingError bool
se, ok := ce.Fun.(*ast.SelectorExpr)
if ok && se.Sel.Name == "Error" {
if typ := f.pkg.typeOf(se.X); typ != nil {
isTestingError = typ.String() == "*testing.T"
}
}
if !isErrorsNew && !isTestingError {
return true
}
if !f.imports("errors") {
return true
}
arg := ce.Args[0]
ce, ok = arg.(*ast.CallExpr)
if !ok || !isPkgDot(ce.Fun, "fmt", "Sprintf") {
return true
}
errorfPrefix := "fmt"
if isTestingError {
errorfPrefix = f.render(se.X)
}
p := f.errorf(node, 1, category("errors"), "should replace %s(fmt.Sprintf(...)) with %s.Errorf(...)", f.render(se), errorfPrefix)
m := f.srcLineWithMatch(ce, `^(.*)`+f.render(se)+`\(fmt\.Sprintf\((.*)\)\)(.*)$`)
if m != nil {
p.ReplacementLine = m[1] + errorfPrefix + ".Errorf(" + m[2] + ")" + m[3]
}
return true
})
}
// lintErrors examines global error vars. It complains if they aren't named in the standard way.
func (f *file) lintErrors() {
for _, decl := range f.f.Decls {
gd, ok := decl.(*ast.GenDecl)
if !ok || gd.Tok != token.VAR {
continue
}
for _, spec := range gd.Specs {
spec := spec.(*ast.ValueSpec)
if len(spec.Names) != 1 || len(spec.Values) != 1 {
continue
}
ce, ok := spec.Values[0].(*ast.CallExpr)
if !ok {
continue
}
if !isPkgDot(ce.Fun, "errors", "New") && !isPkgDot(ce.Fun, "fmt", "Errorf") {
continue
}
id := spec.Names[0]
prefix := "err"
if id.IsExported() {
prefix = "Err"
}
if !strings.HasPrefix(id.Name, prefix) {
f.errorf(id, 0.9, category("naming"), "error var %s should have name of the form %sFoo", id.Name, prefix)
}
}
}
}
func lintErrorString(s string) (isClean bool, conf float64) {
const basicConfidence = 0.8
const capConfidence = basicConfidence - 0.2
first, firstN := utf8.DecodeRuneInString(s)
last, _ := utf8.DecodeLastRuneInString(s)
if last == '.' || last == ':' || last == '!' || last == '\n' {
return false, basicConfidence
}
if unicode.IsUpper(first) {
// People use proper nouns and exported Go identifiers in error strings,
// so decrease the confidence of warnings for capitalization.
if len(s) <= firstN {
return false, capConfidence
}
// Flag strings starting with something that doesn't look like an initialism.
if second, _ := utf8.DecodeRuneInString(s[firstN:]); !unicode.IsUpper(second) {
return false, capConfidence
}
}
return true, 0
}
// lintErrorStrings examines error strings.
// It complains if they are capitalized or end in punctuation or a newline.
func (f *file) lintErrorStrings() {
f.walk(func(node ast.Node) bool {
ce, ok := node.(*ast.CallExpr)
if !ok {
return true
}
if !isPkgDot(ce.Fun, "errors", "New") && !isPkgDot(ce.Fun, "fmt", "Errorf") {
return true
}
if len(ce.Args) < 1 {
return true
}
str, ok := ce.Args[0].(*ast.BasicLit)
if !ok || str.Kind != token.STRING {
return true
}
s, _ := strconv.Unquote(str.Value) // can assume well-formed Go
if s == "" {
return true
}
clean, conf := lintErrorString(s)
if clean {
return true
}
f.errorf(str, conf, link(styleGuideBase+"#error-strings"), category("errors"),
"error strings should not be capitalized or end with punctuation or a newline")
return true
})
}
// lintReceiverNames examines receiver names. It complains about inconsistent
// names used for the same type and names such as "this".
func (f *file) lintReceiverNames() {
typeReceiver := map[string]string{}
f.walk(func(n ast.Node) bool {
fn, ok := n.(*ast.FuncDecl)
if !ok || fn.Recv == nil || len(fn.Recv.List) == 0 {
return true
}
names := fn.Recv.List[0].Names
if len(names) < 1 {
return true
}
name := names[0].Name
const ref = styleGuideBase + "#receiver-names"
if name == "_" {
f.errorf(n, 1, link(ref), category("naming"), `receiver name should not be an underscore, omit the name if it is unused`)
return true
}
if name == "this" || name == "self" {
f.errorf(n, 1, link(ref), category("naming"), `receiver name should be a reflection of its identity; don't use generic names such as "this" or "self"`)
return true
}
recv := receiverType(fn)
if prev, ok := typeReceiver[recv]; ok && prev != name {
f.errorf(n, 1, link(ref), category("naming"), "receiver name %s should be consistent with previous receiver name %s for %s", name, prev, recv)
return true
}
typeReceiver[recv] = name
return true
})
}
// lintIncDec examines statements that increment or decrement a variable.
// It complains if they don't use x++ or x--.
func (f *file) lintIncDec() {
f.walk(func(n ast.Node) bool {
as, ok := n.(*ast.AssignStmt)
if !ok {
return true
}
if len(as.Lhs) != 1 {
return true
}
if !isOne(as.Rhs[0]) {
return true
}
var suffix string
switch as.Tok {
case token.ADD_ASSIGN:
suffix = "++"
case token.SUB_ASSIGN:
suffix = "--"
default:
return true
}
f.errorf(as, 0.8, category("unary-op"), "should replace %s with %s%s", f.render(as), f.render(as.Lhs[0]), suffix)
return true
})
}
// lintErrorReturn examines function declarations that return an error.
// It complains if the error isn't the last parameter.
func (f *file) lintErrorReturn() {
f.walk(func(n ast.Node) bool {
fn, ok := n.(*ast.FuncDecl)
if !ok || fn.Type.Results == nil {
return true
}
ret := fn.Type.Results.List
if len(ret) <= 1 {
return true
}
if isIdent(ret[len(ret)-1].Type, "error") {
return true
}
// An error return parameter should be the last parameter.
// Flag any error parameters found before the last.
for _, r := range ret[:len(ret)-1] {
if isIdent(r.Type, "error") {
f.errorf(fn, 0.9, category("arg-order"), "error should be the last type when returning multiple items")
break // only flag one
}
}
return true
})
}
// lintUnexportedReturn examines exported function declarations.
// It complains if any return an unexported type.
func (f *file) lintUnexportedReturn() {
f.walk(func(n ast.Node) bool {
fn, ok := n.(*ast.FuncDecl)
if !ok {
return true
}
if fn.Type.Results == nil {
return false
}
if !fn.Name.IsExported() {
return false
}
thing := "func"
if fn.Recv != nil && len(fn.Recv.List) > 0 {
thing = "method"
if !ast.IsExported(receiverType(fn)) {
// Don't report exported methods of unexported types,
// such as private implementations of sort.Interface.
return false
}
}
for _, ret := range fn.Type.Results.List {
typ := f.pkg.typeOf(ret.Type)
if exportedType(typ) {
continue
}
f.errorf(ret.Type, 0.8, category("unexported-type-in-api"),
"exported %s %s returns unexported type %s, which can be annoying to use",
thing, fn.Name.Name, typ)
break // only flag one
}
return false
})
}
// exportedType reports whether typ is an exported type.
// It is imprecise, and will err on the side of returning true,
// such as for composite types.
func exportedType(typ types.Type) bool {
switch T := typ.(type) {
case *types.Named:
// Builtin types have no package.
return T.Obj().Pkg() == nil || T.Obj().Exported()
case *types.Map:
return exportedType(T.Key()) && exportedType(T.Elem())
case interface {
Elem() types.Type
}: // array, slice, pointer, chan
return exportedType(T.Elem())
}
// Be conservative about other types, such as struct, interface, etc.
return true
}
// timeSuffixes is a list of name suffixes that imply a time unit.
// This is not an exhaustive list.
var timeSuffixes = []string{
"Sec", "Secs", "Seconds",
"Msec", "Msecs",
"Milli", "Millis", "Milliseconds",
"Usec", "Usecs", "Microseconds",
"MS", "Ms",
}
func (f *file) lintTimeNames() {
f.walk(func(node ast.Node) bool {
v, ok := node.(*ast.ValueSpec)
if !ok {
return true
}
for _, name := range v.Names {
origTyp := f.pkg.typeOf(name)
// Look for time.Duration or *time.Duration;
// the latter is common when using flag.Duration.
typ := origTyp
if pt, ok := typ.(*types.Pointer); ok {
typ = pt.Elem()
}
if !f.pkg.isNamedType(typ, "time", "Duration") {
continue
}
suffix := ""
for _, suf := range timeSuffixes {
if strings.HasSuffix(name.Name, suf) {
suffix = suf
break
}
}
if suffix == "" {
continue
}
f.errorf(v, 0.9, category("time"), "var %s is of type %v; don't use unit-specific suffix %q", name.Name, origTyp, suffix)
}
return true
})
}
// lintContextKeyTypes checks for call expressions to context.WithValue with
// basic types used for the key argument.
// See: https://golang.org/issue/17293
func (f *file) lintContextKeyTypes() {
f.walk(func(node ast.Node) bool {
switch node := node.(type) {
case *ast.CallExpr:
f.checkContextKeyType(node)
}
return true
})
}
// checkContextKeyType reports an error if the call expression calls
// context.WithValue with a key argument of basic type.
func (f *file) checkContextKeyType(x *ast.CallExpr) {
sel, ok := x.Fun.(*ast.SelectorExpr)
if !ok {
return
}
pkg, ok := sel.X.(*ast.Ident)
if !ok || pkg.Name != "context" {
return
}
if sel.Sel.Name != "WithValue" {
return
}
// key is second argument to context.WithValue
if len(x.Args) != 3 {
return
}
key := f.pkg.typesInfo.Types[x.Args[1]]
if ktyp, ok := key.Type.(*types.Basic); ok && ktyp.Kind() != types.Invalid {
f.errorf(x, 1.0, category("context"), fmt.Sprintf("should not use basic type %s as key in context.WithValue", key.Type))
}
}
// lintContextArgs examines function declarations that contain an
// argument with a type of context.Context
// It complains if that argument isn't the first parameter.
func (f *file) lintContextArgs() {
f.walk(func(n ast.Node) bool {
fn, ok := n.(*ast.FuncDecl)
if !ok || len(fn.Type.Params.List) <= 1 {
return true
}
// A context.Context should be the first parameter of a function.
// Flag any that show up after the first.
for _, arg := range fn.Type.Params.List[1:] {
if isPkgDot(arg.Type, "context", "Context") {
f.errorf(fn, 0.9, link("https://golang.org/pkg/context/"), category("arg-order"), "context.Context should be the first parameter of a function")
break // only flag one
}
}
return true
})
}
// containsComments returns whether the interval [start, end) contains any
// comments without "// MATCH " prefix.
func (f *file) containsComments(start, end token.Pos) bool {
for _, cgroup := range f.f.Comments {
comments := cgroup.List
if comments[0].Slash >= end {
// All comments starting with this group are after end pos.
return false
}
if comments[len(comments)-1].Slash < start {
// Comments group ends before start pos.
continue
}
for _, c := range comments {
if start <= c.Slash && c.Slash < end && !strings.HasPrefix(c.Text, "// MATCH ") {
return true
}
}
}
return false
}
// receiverType returns the named type of the method receiver, sans "*",
// or "invalid-type" if fn.Recv is ill formed.
func receiverType(fn *ast.FuncDecl) string {
switch e := fn.Recv.List[0].Type.(type) {
case *ast.Ident:
return e.Name
case *ast.StarExpr:
if id, ok := e.X.(*ast.Ident); ok {
return id.Name
}
}
// The parser accepts much more than just the legal forms.
return "invalid-type"
}
func (f *file) walk(fn func(ast.Node) bool) {
ast.Walk(walker(fn), f.f)
}
func (f *file) render(x interface{}) string {
var buf bytes.Buffer
if err := printer.Fprint(&buf, f.fset, x); err != nil {
panic(err)
}
return buf.String()
}
func (f *file) debugRender(x interface{}) string {
var buf bytes.Buffer
if err := ast.Fprint(&buf, f.fset, x, nil); err != nil {
panic(err)
}
return buf.String()
}
// walker adapts a function to satisfy the ast.Visitor interface.
// The function return whether the walk should proceed into the node's children.
type walker func(ast.Node) bool
func (w walker) Visit(node ast.Node) ast.Visitor {
if w(node) {
return w
}
return nil
}
func isIdent(expr ast.Expr, ident string) bool {
id, ok := expr.(*ast.Ident)
return ok && id.Name == ident
}
// isBlank returns whether id is the blank identifier "_".
// If id == nil, the answer is false.
func isBlank(id *ast.Ident) bool { return id != nil && id.Name == "_" }
func isPkgDot(expr ast.Expr, pkg, name string) bool {
sel, ok := expr.(*ast.SelectorExpr)
return ok && isIdent(sel.X, pkg) && isIdent(sel.Sel, name)
}
func isOne(expr ast.Expr) bool {
lit, ok := expr.(*ast.BasicLit)
return ok && lit.Kind == token.INT && lit.Value == "1"
}
func isCgoExported(f *ast.FuncDecl) bool {
if f.Recv != nil || f.Doc == nil {
return false
}
cgoExport := regexp.MustCompile(fmt.Sprintf("(?m)^//export %s$", regexp.QuoteMeta(f.Name.Name)))
for _, c := range f.Doc.List {
if cgoExport.MatchString(c.Text) {
return true
}
}
return false
}
var basicTypeKinds = map[types.BasicKind]string{
types.UntypedBool: "bool",
types.UntypedInt: "int",
types.UntypedRune: "rune",
types.UntypedFloat: "float64",
types.UntypedComplex: "complex128",
types.UntypedString: "string",
}
// isUntypedConst reports whether expr is an untyped constant,
// and indicates what its default type is.
// scope may be nil.
func (f *file) isUntypedConst(expr ast.Expr) (defType string, ok bool) {
// Re-evaluate expr outside of its context to see if it's untyped.
// (An expr evaluated within, for example, an assignment context will get the type of the LHS.)
exprStr := f.render(expr)
tv, err := types.Eval(f.fset, f.pkg.typesPkg, expr.Pos(), exprStr)
if err != nil {
return "", false
}
if b, ok := tv.Type.(*types.Basic); ok {
if dt, ok := basicTypeKinds[b.Kind()]; ok {
return dt, true
}
}
return "", false
}
// firstLineOf renders the given node and returns its first line.
// It will also match the indentation of another node.
func (f *file) firstLineOf(node, match ast.Node) string {
line := f.render(node)
if i := strings.Index(line, "\n"); i >= 0 {
line = line[:i]
}
return f.indentOf(match) + line
}
func (f *file) indentOf(node ast.Node) string {
line := srcLine(f.src, f.fset.Position(node.Pos()))
for i, r := range line {
switch r {
case ' ', '\t':
default:
return line[:i]
}
}
return line // unusual or empty line
}
func (f *file) srcLineWithMatch(node ast.Node, pattern string) (m []string) {
line := srcLine(f.src, f.fset.Position(node.Pos()))
line = strings.TrimSuffix(line, "\n")
rx := regexp.MustCompile(pattern)
return rx.FindStringSubmatch(line)
}
// imports returns true if the current file imports the specified package path.
func (f *file) imports(importPath string) bool {
all := astutil.Imports(f.fset, f.f)
for _, p := range all {
for _, i := range p {
uq, err := strconv.Unquote(i.Path.Value)
if err == nil && importPath == uq {
return true
}
}
}
return false
}
// srcLine returns the complete line at p, including the terminating newline.
func srcLine(src []byte, p token.Position) string {
// Run to end of line in both directions if not at line start/end.
lo, hi := p.Offset, p.Offset+1
for lo > 0 && src[lo-1] != '\n' {
lo--
}
for hi < len(src) && src[hi-1] != '\n' {
hi++
}
return string(src[lo:hi])
}
|