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// Copyright 2010 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.
Vet examines Go source code and reports suspicious constructs, such as Printf
calls whose arguments do not align with the format string. Vet uses heuristics
that do not guarantee all reports are genuine problems, but it can find errors
not caught by the compilers.
It can be invoked three ways:
By package, from the go tool:
go vet package/path/name
vets the package whose path is provided.
By files:
go tool vet source/directory/*.go
vets the files named, all of which must be in the same package.
By directory:
go tool vet source/directory
recursively descends the directory, vetting each package it finds.
Vet's exit code is 2 for erroneous invocation of the tool, 1 if a
problem was reported, and 0 otherwise. Note that the tool does not
check every possible problem and depends on unreliable heuristics
so it should be used as guidance only, not as a firm indicator of
program correctness.
By default the -all flag is set so all checks are performed.
If any flags are explicitly set to true, only those tests are run. Conversely, if
any flag is explicitly set to false, only those tests are disabled. Thus -printf=true
runs the printf check, -printf=false runs all checks except the printf check.
Available checks:
Assembly declarations
Flag: -asmdecl
Mismatches between assembly files and Go function declarations.
Useless assignments
Flag: -assign
Check for useless assignments.
Atomic mistakes
Flag: -atomic
Common mistaken usages of the sync/atomic package.
Boolean conditions
Flag: -bool
Mistakes involving boolean operators.
Build tags
Flag: -buildtags
Badly formed or misplaced +build tags.
Invalid uses of cgo
Flag: -cgocall
Detect some violations of the cgo pointer passing rules.
Unkeyed composite literals
Flag: -composites
Composite struct literals that do not use the field-keyed syntax.
Copying locks
Flag: -copylocks
Locks that are erroneously passed by value.
Tests, benchmarks and documentation examples
Flag: -tests
Mistakes involving tests including functions with incorrect names or signatures
and example tests that document identifiers not in the package.
Failure to call the cancelation function returned by context.WithCancel.
Flag: -lostcancel
The cancelation function returned by context.WithCancel, WithTimeout,
and WithDeadline must be called or the new context will remain live
until its parent context is cancelled.
(The background context is never cancelled.)
Flag: -methods
Non-standard signatures for methods with familiar names, including:
Format GobEncode GobDecode MarshalJSON MarshalXML
Peek ReadByte ReadFrom ReadRune Scan Seek
UnmarshalJSON UnreadByte UnreadRune WriteByte
Nil function comparison
Flag: -nilfunc
Comparisons between functions and nil.
Printf family
Flag: -printf
Suspicious calls to functions in the Printf family, including any functions
with these names, disregarding case:
Print Printf Println
Fprint Fprintf Fprintln
Sprint Sprintf Sprintln
Error Errorf
Fatal Fatalf
Log Logf
Panic Panicf Panicln
The -printfuncs flag can be used to redefine this list.
If the function name ends with an 'f', the function is assumed to take
a format descriptor string in the manner of fmt.Printf. If not, vet
complains about arguments that look like format descriptor strings.
It also checks for errors such as using a Writer as the first argument of
Struct tags
Range loop variables
Flag: -rangeloops
Incorrect uses of range loop variables in closures.
Shadowed variables
Flag: -shadow=false (experimental; must be set explicitly)
Variables that may have been unintentionally shadowed.
Flag: -shift
Shifts equal to or longer than the variable's length.
Flag: -structtags
Struct tags that do not follow the format understood by reflect.StructTag.Get.
Well-known encoding struct tags (json, xml) used with unexported fields.
Unreachable code
Flag: -unreachable
Unreachable code.
Misuse of unsafe Pointers
Flag: -unsafeptr
Likely incorrect uses of unsafe.Pointer to convert integers to pointers.
A conversion from uintptr to unsafe.Pointer is invalid if it implies that
there is a uintptr-typed word in memory that holds a pointer value,
because that word will be invisible to stack copying and to the garbage
Unused result of certain function calls
Flag: -unusedresult
Calls to well-known functions and methods that return a value that is
discarded. By default, this includes functions like fmt.Errorf and
fmt.Sprintf and methods like String and Error. The flags -unusedfuncs
and -unusedstringmethods control the set.
Other flags
These flags configure the behavior of vet:
-all (default true)
Enable all non-experimental checks.
Verbose mode
A comma-separated list of print-like function names
to supplement the standard list.
For more information, see the discussion of the -printf flag.
Whether to be strict about shadowing; can be noisy.
package main