1 // Copyright 2010 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 /* 6 7 Vet examines Go source code and reports suspicious constructs, such as Printf 8 calls whose arguments do not align with the format string. Vet uses heuristics 9 that do not guarantee all reports are genuine problems, but it can find errors 10 not caught by the compilers. 11 12 Vet is normally invoked using the go command by running "go vet": 13 14 go vet 15 vets the package in the current directory. 16 17 go vet package/path/name 18 vets the package whose path is provided. 19 20 Use "go help packages" to see other ways of specifying which packages to vet. 21 22 Vet's exit code is 2 for erroneous invocation of the tool, 1 if a 23 problem was reported, and 0 otherwise. Note that the tool does not 24 check every possible problem and depends on unreliable heuristics 25 so it should be used as guidance only, not as a firm indicator of 26 program correctness. 27 28 By default the -all flag is set so all checks are performed. 29 If any flags are explicitly set to true, only those tests are run. Conversely, if 30 any flag is explicitly set to false, only those tests are disabled. Thus -printf=true 31 runs the printf check, -printf=false runs all checks except the printf check. 32 33 By default vet uses the object files generated by 'go install some/pkg' to typecheck the code. 34 If the -source flag is provided, vet uses only source code. 35 36 Available checks: 37 38 Assembly declarations 39 40 Flag: -asmdecl 41 42 Mismatches between assembly files and Go function declarations. 43 44 Useless assignments 45 46 Flag: -assign 47 48 Check for useless assignments. 49 50 Atomic mistakes 51 52 Flag: -atomic 53 54 Common mistaken usages of the sync/atomic package. 55 56 Boolean conditions 57 58 Flag: -bool 59 60 Mistakes involving boolean operators. 61 62 Build tags 63 64 Flag: -buildtags 65 66 Badly formed or misplaced +build tags. 67 68 Invalid uses of cgo 69 70 Flag: -cgocall 71 72 Detect some violations of the cgo pointer passing rules. 73 74 Unkeyed composite literals 75 76 Flag: -composites 77 78 Composite struct literals that do not use the field-keyed syntax. 79 80 Copying locks 81 82 Flag: -copylocks 83 84 Locks that are erroneously passed by value. 85 86 HTTP responses used incorrectly 87 88 Flag: -httpresponse 89 90 Mistakes deferring a function call on an HTTP response before 91 checking whether the error returned with the response was nil. 92 93 Failure to call the cancelation function returned by WithCancel 94 95 Flag: -lostcancel 96 97 The cancelation function returned by context.WithCancel, WithTimeout, 98 and WithDeadline must be called or the new context will remain live 99 until its parent context is cancelled. 100 (The background context is never cancelled.) 101 102 Methods 103 104 Flag: -methods 105 106 Non-standard signatures for methods with familiar names, including: 107 Format GobEncode GobDecode MarshalJSON MarshalXML 108 Peek ReadByte ReadFrom ReadRune Scan Seek 109 UnmarshalJSON UnreadByte UnreadRune WriteByte 110 WriteTo 111 112 Nil function comparison 113 114 Flag: -nilfunc 115 116 Comparisons between functions and nil. 117 118 Printf family 119 120 Flag: -printf 121 122 Suspicious calls to functions in the Printf family, including any functions 123 with these names, disregarding case: 124 Print Printf Println 125 Fprint Fprintf Fprintln 126 Sprint Sprintf Sprintln 127 Error Errorf 128 Fatal Fatalf 129 Log Logf 130 Panic Panicf Panicln 131 The -printfuncs flag can be used to redefine this list. 132 If the function name ends with an 'f', the function is assumed to take 133 a format descriptor string in the manner of fmt.Printf. If not, vet 134 complains about arguments that look like format descriptor strings. 135 136 It also checks for errors such as using a Writer as the first argument of 137 Printf. 138 139 Range loop variables 140 141 Flag: -rangeloops 142 143 Incorrect uses of range loop variables in closures. 144 145 Shadowed variables 146 147 Flag: -shadow=false (experimental; must be set explicitly) 148 149 Variables that may have been unintentionally shadowed. 150 151 Shifts 152 153 Flag: -shift 154 155 Shifts equal to or longer than the variable's length. 156 157 Struct tags 158 159 Flag: -structtags 160 161 Struct tags that do not follow the format understood by reflect.StructTag.Get. 162 Well-known encoding struct tags (json, xml) used with unexported fields. 163 164 Tests and documentation examples 165 166 Flag: -tests 167 168 Mistakes involving tests including functions with incorrect names or signatures 169 and example tests that document identifiers not in the package. 170 171 Unreachable code 172 173 Flag: -unreachable 174 175 Unreachable code. 176 177 Misuse of unsafe Pointers 178 179 Flag: -unsafeptr 180 181 Likely incorrect uses of unsafe.Pointer to convert integers to pointers. 182 A conversion from uintptr to unsafe.Pointer is invalid if it implies that 183 there is a uintptr-typed word in memory that holds a pointer value, 184 because that word will be invisible to stack copying and to the garbage 185 collector. 186 187 Unused result of certain function calls 188 189 Flag: -unusedresult 190 191 Calls to well-known functions and methods that return a value that is 192 discarded. By default, this includes functions like fmt.Errorf and 193 fmt.Sprintf and methods like String and Error. The flags -unusedfuncs 194 and -unusedstringmethods control the set. 195 196 Other flags 197 198 These flags configure the behavior of vet: 199 200 -all (default true) 201 Enable all non-experimental checks. 202 -v 203 Verbose mode 204 -printfuncs 205 A comma-separated list of print-like function names 206 to supplement the standard list. 207 For more information, see the discussion of the -printf flag. 208 -shadowstrict 209 Whether to be strict about shadowing; can be noisy. 210 211 Using vet directly 212 213 For testing and debugging vet can be run directly by invoking 214 "go tool vet" or just running the binary. Run this way, vet might not 215 have up to date information for imported packages. 216 217 go tool vet source/directory/*.go 218 vets the files named, all of which must be in the same package. 219 220 go tool vet source/directory 221 recursively descends the directory, vetting each package it finds. 222 223 */ 224 package main 225
