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
|
// Copyright 2023 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 inline_test
import (
"fmt"
"go/ast"
"go/parser"
"go/token"
"go/types"
"testing"
"golang.org/x/tools/internal/refactor/inline"
)
// TestCalleeEffects is a unit test of the calleefx analysis.
func TestCalleeEffects(t *testing.T) {
// Each callee must declare a function or method named f.
const funcName = "f"
var tests = []struct {
descr string
callee string // Go source file (sans package decl) containing callee decl
want string // expected effects string (-1=R∞ -2=W∞)
}{
{
"Assignments have unknown effects.",
`func f(x, y int) { x = y }`,
`[0 1 -2]`,
},
{
"Reads from globals are impure.",
`func f() { _ = g }; var g int`,
`[-1]`,
},
{
"Writes to globals have effects.",
`func f() { g = 0 }; var g int`,
`[-1 -2]`, // the -1 is spurious but benign
},
{
"Blank assign has no effect.",
`func f(x int) { _ = x }`,
`[0]`,
},
{
"Short decl of new var has has no effect.",
`func f(x int) { y := x; _ = y }`,
`[0]`,
},
{
"Short decl of existing var (y) is an assignment.",
`func f(x int) { y := x; y, z := 1, 2; _, _ = y, z }`,
`[0 -2]`,
},
{
"Unreferenced parameters are excluded.",
`func f(x, y, z int) { _ = z + x }`,
`[2 0]`,
},
{
"Built-in len has no effect.",
`func f(x, y string) { _ = len(y) + len(x) }`,
`[1 0]`,
},
{
"Built-in println has effects.",
`func f(x, y int) { println(y, x) }`,
`[1 0 -2]`,
},
{
"Return has no effect, and no control successor.",
`func f(x, y int) int { return x + y; panic(1) }`,
`[0 1]`,
},
{
"Loops (etc) have unknown effects.",
`func f(x, y bool) { for x { _ = y } }`,
`[0 -2 1]`,
},
{
"Calls have unknown effects.",
`func f(x, y int) { _, _, _ = x, g(), y }; func g() int`,
`[0 -2 1]`,
},
{
"Calls to some built-ins are pure.",
`func f(x, y int) { _, _, _ = x, len("hi"), y }`,
`[0 1]`,
},
{
"Calls to some built-ins are pure (variant).",
`func f(x, y int) { s := "hi"; _, _, _ = x, len(s), y; s = "bye" }`,
`[0 1 -2]`,
},
{
"Calls to some built-ins are pure (another variants).",
`func f(x, y int) { s := "hi"; _, _, _ = x, len(s), y }`,
`[0 1]`,
},
{
"Reading a local var is impure but does not have effects.",
`func f(x, y bool) { for x { _ = y } }`,
`[0 -2 1]`,
},
}
for _, test := range tests {
test := test
t.Run(test.descr, func(t *testing.T) {
fset := token.NewFileSet()
mustParse := func(filename string, content any) *ast.File {
f, err := parser.ParseFile(fset, filename, content, parser.ParseComments|parser.SkipObjectResolution)
if err != nil {
t.Fatalf("ParseFile: %v", err)
}
return f
}
// Parse callee file and find first func decl named f.
calleeContent := "package p\n" + test.callee
calleeFile := mustParse("callee.go", calleeContent)
var decl *ast.FuncDecl
for _, d := range calleeFile.Decls {
if d, ok := d.(*ast.FuncDecl); ok && d.Name.Name == funcName {
decl = d
break
}
}
if decl == nil {
t.Fatalf("declaration of func %s not found: %s", funcName, test.callee)
}
info := &types.Info{
Defs: make(map[*ast.Ident]types.Object),
Uses: make(map[*ast.Ident]types.Object),
Types: make(map[ast.Expr]types.TypeAndValue),
Implicits: make(map[ast.Node]types.Object),
Selections: make(map[*ast.SelectorExpr]*types.Selection),
Scopes: make(map[ast.Node]*types.Scope),
}
conf := &types.Config{Error: func(err error) { t.Error(err) }}
pkg, err := conf.Check("p", fset, []*ast.File{calleeFile}, info)
if err != nil {
t.Fatal(err)
}
callee, err := inline.AnalyzeCallee(t.Logf, fset, pkg, info, decl, []byte(calleeContent))
if err != nil {
t.Fatal(err)
}
if got := fmt.Sprint(callee.Effects()); got != test.want {
t.Errorf("for effects of %s, got %s want %s",
test.callee, got, test.want)
}
})
}
}
|
