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
|
// Copyright 2012 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.
// Package composite defines an Analyzer that checks for unkeyed
// composite literals.
package composite
import (
"go/ast"
"go/types"
"strings"
"golang.org/x/tools/go/analysis"
"golang.org/x/tools/go/analysis/passes/inspect"
"golang.org/x/tools/go/ast/inspector"
)
const Doc = `checked for unkeyed composite literals
This analyzer reports a diagnostic for composite literals of struct
types imported from another package that do not use the field-keyed
syntax. Such literals are fragile because the addition of a new field
(even if unexported) to the struct will cause compilation to fail.`
var Analyzer = &analysis.Analyzer{
Name: "composites",
Doc: Doc,
Requires: []*analysis.Analyzer{inspect.Analyzer},
RunDespiteErrors: true,
Run: run,
}
var whitelist = true
func init() {
Analyzer.Flags.BoolVar(&whitelist, "whitelist", whitelist, "use composite white list; for testing only")
}
// runUnkeyedLiteral checks if a composite literal is a struct literal with
// unkeyed fields.
func run(pass *analysis.Pass) (interface{}, error) {
inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
nodeFilter := []ast.Node{
(*ast.CompositeLit)(nil),
}
inspect.Preorder(nodeFilter, func(n ast.Node) {
cl := n.(*ast.CompositeLit)
typ := pass.TypesInfo.Types[cl].Type
if typ == nil {
// cannot determine composite literals' type, skip it
return
}
typeName := typ.String()
if whitelist && unkeyedLiteral[typeName] {
// skip whitelisted types
return
}
under := typ.Underlying()
for {
ptr, ok := under.(*types.Pointer)
if !ok {
break
}
under = ptr.Elem().Underlying()
}
if _, ok := under.(*types.Struct); !ok {
// skip non-struct composite literals
return
}
if isLocalType(pass, typ) {
// allow unkeyed locally defined composite literal
return
}
// check if the CompositeLit contains an unkeyed field
allKeyValue := true
for _, e := range cl.Elts {
if _, ok := e.(*ast.KeyValueExpr); !ok {
allKeyValue = false
break
}
}
if allKeyValue {
// all the composite literal fields are keyed
return
}
pass.Reportf(cl.Pos(), "%s composite literal uses unkeyed fields", typeName)
})
return nil, nil
}
func isLocalType(pass *analysis.Pass, typ types.Type) bool {
switch x := typ.(type) {
case *types.Struct:
// struct literals are local types
return true
case *types.Pointer:
return isLocalType(pass, x.Elem())
case *types.Named:
// names in package foo are local to foo_test too
return strings.TrimSuffix(x.Obj().Pkg().Path(), "_test") == strings.TrimSuffix(pass.Pkg.Path(), "_test")
}
return false
}
|
