Documentation

Overview

    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.

    Vet is normally invoked through the go command. This command vets the package in the current directory:

    go vet
    

    whereas this one vets the packages whose path is provided:

    go vet my/project/...
    

    Use "go help packages" to see other ways of specifying which packages to vet.

    Vet's exit code is non-zero for erroneous invocation of the tool or 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.

    To list the available checks, run "go tool vet help":

    asmdecl      report mismatches between assembly files and Go declarations
    assign       check for useless assignments
    atomic       check for common mistakes using the sync/atomic package
    bools        check for common mistakes involving boolean operators
    buildtag     check that +build tags are well-formed and correctly located
    cgocall      detect some violations of the cgo pointer passing rules
    composites   check for unkeyed composite literals
    copylocks    check for locks erroneously passed by value
    httpresponse check for mistakes using HTTP responses
    loopclosure  check references to loop variables from within nested functions
    lostcancel   check cancel func returned by context.WithCancel is called
    nilfunc      check for useless comparisons between functions and nil
    printf       check consistency of Printf format strings and arguments
    shift        check for shifts that equal or exceed the width of the integer
    stdmethods   check signature of methods of well-known interfaces
    structtag    check that struct field tags conform to reflect.StructTag.Get
    tests        check for common mistaken usages of tests and examples
    unmarshal    report passing non-pointer or non-interface values to unmarshal
    unreachable  check for unreachable code
    unsafeptr    check for invalid conversions of uintptr to unsafe.Pointer
    unusedresult check for unused results of calls to some functions
    

    For details and flags of a particular check, such as printf, run "go tool vet help printf".

    By default, 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, and -printf=false runs all checks except the printf check.

    For information on writing a new check, see golang.org/x/tools/go/analysis.

    Core flags:

    -c=N
      	display offending line plus N lines of surrounding context
    -json
      	emit analysis diagnostics (and errors) in JSON format
    

    Source Files