Source file test/defererrcheck.go

     1  // errorcheck -0 -l -d=defer
     2  
     3  // Copyright 2019 The Go Authors. All rights reserved.
     4  // Use of this source code is governed by a BSD-style
     5  // license that can be found in the LICENSE file.
     6  
     7  // check that open-coded defers are used in expected situations
     8  
     9  package main
    10  
    11  import "fmt"
    12  
    13  var glob = 3
    14  
    15  func f1() {
    16  
    17  	for i := 0; i < 10; i++ {
    18  		fmt.Println("loop")
    19  	}
    20  	defer func() { // ERROR "open-coded defer"
    21  		fmt.Println("defer")
    22  	}()
    23  }
    24  
    25  func f2() {
    26  	for {
    27  		defer func() { // ERROR "heap-allocated defer"
    28  			fmt.Println("defer1")
    29  		}()
    30  		if glob > 2 {
    31  			break
    32  		}
    33  	}
    34  	defer func() { // ERROR "stack-allocated defer"
    35  		fmt.Println("defer2")
    36  	}()
    37  }
    38  
    39  func f3() {
    40  	defer func() { // ERROR "stack-allocated defer"
    41  		fmt.Println("defer2")
    42  	}()
    43  	for {
    44  		defer func() { // ERROR "heap-allocated defer"
    45  			fmt.Println("defer1")
    46  		}()
    47  		if glob > 2 {
    48  			break
    49  		}
    50  	}
    51  }
    52  
    53  func f4() {
    54  	defer func() { // ERROR "open-coded defer"
    55  		fmt.Println("defer")
    56  	}()
    57  label:
    58  	fmt.Println("goto loop")
    59  	if glob > 2 {
    60  		goto label
    61  	}
    62  }
    63  
    64  func f5() {
    65  label:
    66  	fmt.Println("goto loop")
    67  	defer func() { // ERROR "heap-allocated defer"
    68  		fmt.Println("defer")
    69  	}()
    70  	if glob > 2 {
    71  		goto label
    72  	}
    73  }
    74  
    75  func f6() {
    76  label:
    77  	fmt.Println("goto loop")
    78  	if glob > 2 {
    79  		goto label
    80  	}
    81  	// The current analysis doesn't end a backward goto loop, so this defer is
    82  	// considered to be inside a loop
    83  	defer func() { // ERROR "heap-allocated defer"
    84  		fmt.Println("defer")
    85  	}()
    86  }
    87  
    88  // Test for function with too many exits, which will disable open-coded defer
    89  // even though the number of defer statements is not greater than 8.
    90  func f7() {
    91  	defer println(1) // ERROR "open-coded defer"
    92  	defer println(1) // ERROR "open-coded defer"
    93  	defer println(1) // ERROR "open-coded defer"
    94  	defer println(1) // ERROR "open-coded defer"
    95  
    96  	switch glob {
    97  	case 1:
    98  		return
    99  	case 2:
   100  		return
   101  	case 3:
   102  		return
   103  	}
   104  }
   105  
   106  func f8() {
   107  	defer println(1) // ERROR "stack-allocated defer"
   108  	defer println(1) // ERROR "stack-allocated defer"
   109  	defer println(1) // ERROR "stack-allocated defer"
   110  	defer println(1) // ERROR "stack-allocated defer"
   111  
   112  	switch glob {
   113  	case 1:
   114  		return
   115  	case 2:
   116  		return
   117  	case 3:
   118  		return
   119  	case 4:
   120  		return
   121  	}
   122  }
   123  
   124  func f9() {
   125  	defer println(1) // ERROR "open-coded defer"
   126  	defer println(1) // ERROR "open-coded defer"
   127  	defer println(1) // ERROR "open-coded defer"
   128  	defer println(1) // ERROR "open-coded defer"
   129  
   130  	switch glob {
   131  	case 1:
   132  		return
   133  	case 2:
   134  		return
   135  	case 3:
   136  		return
   137  	case 4:
   138  		panic("")
   139  	}
   140  }
   141  

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