| 1 | // Copyright 2016 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 | package a |
| 6 | |
| 7 | import ( |
| 8 | "context" |
| 9 | "log" |
| 10 | "os" |
| 11 | "testing" |
| 12 | "time" |
| 13 | ) |
| 14 | |
| 15 | var bg = context.Background() |
| 16 | |
| 17 | // Check the three functions and assignment forms (var, :=, =) we look for. |
| 18 | // (Do these early: line numbers are fragile.) |
| 19 | func _() { |
| 20 | var _, cancel = context.WithCancel(bg) // want `the cancel function is not used on all paths \(possible context leak\)` |
| 21 | if false { |
| 22 | _ = cancel |
| 23 | } |
| 24 | } // want "this return statement may be reached without using the cancel var defined on line 20" |
| 25 | |
| 26 | func _() { |
| 27 | _, cancel2 := context.WithDeadline(bg, time.Time{}) // want "the cancel2 function is not used..." |
| 28 | if false { |
| 29 | _ = cancel2 |
| 30 | } |
| 31 | } // want "may be reached without using the cancel2 var defined on line 27" |
| 32 | |
| 33 | func _() { |
| 34 | var cancel3 func() |
| 35 | _, cancel3 = context.WithTimeout(bg, 0) // want "function is not used..." |
| 36 | if false { |
| 37 | _ = cancel3 |
| 38 | } |
| 39 | } // want "this return statement may be reached without using the cancel3 var defined on line 35" |
| 40 | |
| 41 | func _() { |
| 42 | ctx, _ := context.WithCancel(bg) // want "the cancel function returned by context.WithCancel should be called, not discarded, to avoid a context leak" |
| 43 | ctx, _ = context.WithTimeout(bg, 0) // want "the cancel function returned by context.WithTimeout should be called, not discarded, to avoid a context leak" |
| 44 | ctx, _ = context.WithDeadline(bg, time.Time{}) // want "the cancel function returned by context.WithDeadline should be called, not discarded, to avoid a context leak" |
| 45 | _ = ctx |
| 46 | } |
| 47 | |
| 48 | func _() { |
| 49 | _, cancel := context.WithCancel(bg) |
| 50 | defer cancel() // ok |
| 51 | } |
| 52 | |
| 53 | func _() { |
| 54 | _, cancel := context.WithCancel(bg) // want "not used on all paths" |
| 55 | if condition { |
| 56 | cancel() |
| 57 | } |
| 58 | return // want "this return statement may be reached without using the cancel var" |
| 59 | } |
| 60 | |
| 61 | func _() { |
| 62 | _, cancel := context.WithCancel(bg) |
| 63 | if condition { |
| 64 | cancel() |
| 65 | } else { |
| 66 | // ok: infinite loop |
| 67 | for { |
| 68 | print(0) |
| 69 | } |
| 70 | } |
| 71 | } |
| 72 | |
| 73 | func _() { |
| 74 | _, cancel := context.WithCancel(bg) // want "not used on all paths" |
| 75 | if condition { |
| 76 | cancel() |
| 77 | } else { |
| 78 | for i := 0; i < 10; i++ { |
| 79 | print(0) |
| 80 | } |
| 81 | } |
| 82 | } // want "this return statement may be reached without using the cancel var" |
| 83 | |
| 84 | func _() { |
| 85 | _, cancel := context.WithCancel(bg) |
| 86 | // ok: used on all paths |
| 87 | switch someInt { |
| 88 | case 0: |
| 89 | new(testing.T).FailNow() |
| 90 | case 1: |
| 91 | log.Fatal() |
| 92 | case 2: |
| 93 | cancel() |
| 94 | case 3: |
| 95 | print("hi") |
| 96 | fallthrough |
| 97 | default: |
| 98 | os.Exit(1) |
| 99 | } |
| 100 | } |
| 101 | |
| 102 | func _() { |
| 103 | _, cancel := context.WithCancel(bg) // want "not used on all paths" |
| 104 | switch someInt { |
| 105 | case 0: |
| 106 | new(testing.T).FailNow() |
| 107 | case 1: |
| 108 | log.Fatal() |
| 109 | case 2: |
| 110 | cancel() |
| 111 | case 3: |
| 112 | print("hi") // falls through to implicit return |
| 113 | default: |
| 114 | os.Exit(1) |
| 115 | } |
| 116 | } // want "this return statement may be reached without using the cancel var" |
| 117 | |
| 118 | func _(ch chan int) { |
| 119 | _, cancel := context.WithCancel(bg) // want "not used on all paths" |
| 120 | select { |
| 121 | case <-ch: |
| 122 | new(testing.T).FailNow() |
| 123 | case ch <- 2: |
| 124 | print("hi") // falls through to implicit return |
| 125 | case ch <- 1: |
| 126 | cancel() |
| 127 | default: |
| 128 | os.Exit(1) |
| 129 | } |
| 130 | } // want "this return statement may be reached without using the cancel var" |
| 131 | |
| 132 | func _(ch chan int) { |
| 133 | _, cancel := context.WithCancel(bg) |
| 134 | // A blocking select must execute one of its cases. |
| 135 | select { |
| 136 | case <-ch: |
| 137 | panic(0) |
| 138 | } |
| 139 | if false { |
| 140 | _ = cancel |
| 141 | } |
| 142 | } |
| 143 | |
| 144 | func _() { |
| 145 | go func() { |
| 146 | ctx, cancel := context.WithCancel(bg) // want "not used on all paths" |
| 147 | if false { |
| 148 | _ = cancel |
| 149 | } |
| 150 | print(ctx) |
| 151 | }() // want "may be reached without using the cancel var" |
| 152 | } |
| 153 | |
| 154 | var condition bool |
| 155 | var someInt int |
| 156 | |
| 157 | // Regression test for Go issue 16143. |
| 158 | func _() { |
| 159 | var x struct{ f func() } |
| 160 | x.f() |
| 161 | } |
| 162 | |
| 163 | // Regression test for Go issue 16230. |
| 164 | func _() (ctx context.Context, cancel func()) { |
| 165 | ctx, cancel = context.WithCancel(bg) |
| 166 | return // a naked return counts as a load of the named result values |
| 167 | } |
| 168 | |
| 169 | // Same as above, but for literal function. |
| 170 | var _ = func() (ctx context.Context, cancel func()) { |
| 171 | ctx, cancel = context.WithCancel(bg) |
| 172 | return |
| 173 | } |
| 174 | |
| 175 | // Test for Go issue 31856. |
| 176 | func _() { |
| 177 | var cancel func() |
| 178 | |
| 179 | func() { |
| 180 | _, cancel = context.WithCancel(bg) |
| 181 | }() |
| 182 | |
| 183 | cancel() |
| 184 | } |
| 185 | |
| 186 | var cancel1 func() |
| 187 | |
| 188 | // Same as above, but for package-level cancel variable. |
| 189 | func _() { |
| 190 | // We assume that other uses of cancel1 exist. |
| 191 | _, cancel1 = context.WithCancel(bg) |
| 192 | } |
| 193 |
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