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Commit b618f326 authored by Rob Pike's avatar Rob Pike
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govet: divide the program into one file per vetting suite 

Just a rearrangement except for a couple of new functions
and names so govet.go can have all the generic walk routines.

R=rsc
CC=golang-dev
https://golang.org/cl/5489058
parent 04faa08c
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Inline Side-by-side
Showing with 432 additions and 373 deletions
src/cmd/govet/Makefile
View file @ b618f326
......@@ -7,6 +7,9 @@ include ../../Make.inc
TARG=govet
GOFILES=\
govet.go\
method.go\
print.go\
structtag.go\
include ../../Make.cmd
......
src/cmd/govet/govet.go
View file @ b618f326
......@@ -12,19 +12,15 @@ import (
"fmt"
"go/ast"
"go/parser"
"go/printer"
"go/token"
"io"
"os"
"path/filepath"
"reflect"
"strconv"
"strings"
"unicode/utf8"
)
var verbose = flag.Bool("v", false, "verbose")
var printfuncs = flag.String("printfuncs", "", "comma-separated list of print function names to check")
var exitCode = 0
// setExit sets the value for os.Exit when it is called, later. It
......@@ -102,7 +98,7 @@ func doFile(name string, reader io.Reader) {
return
}
file := &File{fset: fs, file: parsedFile}
file.checkFile(name, parsedFile)
file.walkFile(name, parsedFile)
}
func visit(path string, f os.FileInfo, err error) error {
......@@ -168,8 +164,8 @@ func (f *File) Warnf(pos token.Pos, format string, args ...interface{}) {
fmt.Fprintf(os.Stderr, loc+format+"\n", args...)
}
// checkFile checks all the top-level declarations in a file.
func (f *File) checkFile(name string, file *ast.File) {
// walkFile walks the file's tree.
func (f *File) walkFile(name string, file *ast.File) {
Println("Checking file", name)
ast.Walk(f, file)
}
......@@ -178,396 +174,59 @@ func (f *File) checkFile(name string, file *ast.File) {
func (f *File) Visit(node ast.Node) ast.Visitor {
switch n := node.(type) {
case *ast.CallExpr:
f.checkCallExpr(n)
f.walkCallExpr(n)
case *ast.Field:
f.checkFieldTag(n)
f.walkFieldTag(n)
case *ast.FuncDecl:
f.checkMethodDecl(n)
f.walkMethodDecl(n)
case *ast.InterfaceType:
f.checkInterfaceType(n)
f.walkInterfaceType(n)
}
return f
}
// checkMethodDecl checks for canonical method signatures
// in method declarations.
func (f *File) checkMethodDecl(d *ast.FuncDecl) {
if d.Recv == nil {
// not a method
return
}
f.checkMethod(d.Name, d.Type)
}
// checkInterfaceType checks for canonical method signatures
// in interface definitions.
func (f *File) checkInterfaceType(t *ast.InterfaceType) {
for _, field := range t.Methods.List {
for _, id := range field.Names {
f.checkMethod(id, field.Type.(*ast.FuncType))
}
}
}
type MethodSig struct {
args []string
results []string
}
// canonicalMethods lists the input and output types for Go methods
// that are checked using dynamic interface checks. Because the
// checks are dynamic, such methods would not cause a compile error
// if they have the wrong signature: instead the dynamic check would
// fail, sometimes mysteriously. If a method is found with a name listed
// here but not the input/output types listed here, govet complains.
//
// A few of the canonical methods have very common names.
// For example, a type might implement a Scan method that
// has nothing to do with fmt.Scanner, but we still want to check
// the methods that are intended to implement fmt.Scanner.
// To do that, the arguments that have a + prefix are treated as
// signals that the canonical meaning is intended: if a Scan
// method doesn't have a fmt.ScanState as its first argument,
// we let it go. But if it does have a fmt.ScanState, then the
// rest has to match.
var canonicalMethods = map[string]MethodSig{
// "Flush": {{}, {"error"}}, // http.Flusher and jpeg.writer conflict
"Format": {[]string{"=fmt.State", "rune"}, []string{}}, // fmt.Formatter
"GobDecode": {[]string{"[]byte"}, []string{"error"}}, // gob.GobDecoder
"GobEncode": {[]string{}, []string{"[]byte", "error"}}, // gob.GobEncoder
"MarshalJSON": {[]string{}, []string{"[]byte", "error"}}, // json.Marshaler
"MarshalXML": {[]string{}, []string{"[]byte", "error"}}, // xml.Marshaler
"Peek": {[]string{"=int"}, []string{"[]byte", "error"}}, // image.reader (matching bufio.Reader)
"ReadByte": {[]string{}, []string{"byte", "error"}}, // io.ByteReader
"ReadFrom": {[]string{"=io.Reader"}, []string{"int64", "error"}}, // io.ReaderFrom
"ReadRune": {[]string{}, []string{"rune", "int", "error"}}, // io.RuneReader
"Scan": {[]string{"=fmt.ScanState", "rune"}, []string{"error"}}, // fmt.Scanner
"Seek": {[]string{"=int64", "int"}, []string{"int64", "error"}}, // io.Seeker
"UnmarshalJSON": {[]string{"[]byte"}, []string{"error"}}, // json.Unmarshaler
"UnreadByte": {[]string{}, []string{"error"}},
"UnreadRune": {[]string{}, []string{"error"}},
"WriteByte": {[]string{"byte"}, []string{"error"}}, // jpeg.writer (matching bufio.Writer)
"WriteTo": {[]string{"=io.Writer"}, []string{"int64", "error"}}, // io.WriterTo
// walkCall walks a call expression.
func (f *File) walkCall(call *ast.CallExpr, name string) {
f.checkFmtPrintfCall(call, name)
}
func (f *File) checkMethod(id *ast.Ident, t *ast.FuncType) {
// Expected input/output.
expect, ok := canonicalMethods[id.Name]
if !ok {
return
}
// Actual input/output
args := typeFlatten(t.Params.List)
var results []ast.Expr
if t.Results != nil {
results = typeFlatten(t.Results.List)
}
// Do the =s (if any) all match?
if !f.matchParams(expect.args, args, "=") || !f.matchParams(expect.results, results, "=") {
// walkFieldTag walks a struct field tag.
func (f *File) walkFieldTag(field *ast.Field) {
if field.Tag == nil {
return
}
// Everything must match.
if !f.matchParams(expect.args, args, "") || !f.matchParams(expect.results, results, "") {
expectFmt := id.Name + "(" + argjoin(expect.args) + ")"
if len(expect.results) == 1 {
expectFmt += " " + argjoin(expect.results)
} else if len(expect.results) > 1 {
expectFmt += " (" + argjoin(expect.results) + ")"
}
f.b.Reset()
if err := printer.Fprint(&f.b, f.fset, t); err != nil {
fmt.Fprintf(&f.b, "<%s>", err)
}
actual := f.b.String()
if strings.HasPrefix(actual, "func(") {
actual = actual[4:]
}
actual = id.Name + actual
f.Warnf(id.Pos(), "method %s should have signature %s", actual, expectFmt)
}
f.checkCanonicalFieldTag(field)
}
func argjoin(x []string) string {
y := make([]string, len(x))
for i, s := range x {
if s[0] == '=' {
s = s[1:]
}
y[i] = s
}
return strings.Join(y, ", ")
// walkMethodDecl walks the method's signature.
func (f *File) walkMethod(id *ast.Ident, t *ast.FuncType) {
f.checkCanonicalMethod(id, t)
}
// Turn parameter list into slice of types
// (in the ast, types are Exprs).
// Have to handle f(int, bool) and f(x, y, z int)
// so not a simple 1-to-1 conversion.
func typeFlatten(l []*ast.Field) []ast.Expr {
var t []ast.Expr
for _, f := range l {
if len(f.Names) == 0 {
t = append(t, f.Type)
continue
}
for _ = range f.Names {
t = append(t, f.Type)
}
// walkMethodDecl walks the method signature in the declaration.
func (f *File) walkMethodDecl(d *ast.FuncDecl) {
if d.Recv == nil {
// not a method
return
}
return t
f.walkMethod(d.Name, d.Type)
}
// Does each type in expect with the given prefix match the corresponding type in actual?
func (f *File) matchParams(expect []string, actual []ast.Expr, prefix string) bool {
for i, x := range expect {
if !strings.HasPrefix(x, prefix) {
continue
}
if i >= len(actual) {
return false
}
if !f.matchParamType(x, actual[i]) {
return false
// walkInterfaceType walks the method signatures of an interface.
func (f *File) walkInterfaceType(t *ast.InterfaceType) {
for _, field := range t.Methods.List {
for _, id := range field.Names {
f.walkMethod(id, field.Type.(*ast.FuncType))
}
}
if prefix == "" && len(actual) > len(expect) {
return false
}
return true
}
// Does this one type match?
func (f *File) matchParamType(expect string, actual ast.Expr) bool {
if strings.HasPrefix(expect, "=") {
expect = expect[1:]
}
// Strip package name if we're in that package.
if n := len(f.file.Name.Name); len(expect) > n && expect[:n] == f.file.Name.Name && expect[n] == '.' {
expect = expect[n+1:]
}
// Overkill but easy.
f.b.Reset()
printer.Fprint(&f.b, f.fset, actual)
return f.b.String() == expect
}
// checkField checks a struct field tag.
func (f *File) checkFieldTag(field *ast.Field) {
if field.Tag == nil {
return
}
tag, err := strconv.Unquote(field.Tag.Value)
if err != nil {
f.Warnf(field.Pos(), "unable to read struct tag %s", field.Tag.Value)
return
}
// Check tag for validity by appending
// new key:value to end and checking that
// the tag parsing code can find it.
if reflect.StructTag(tag+` _gofix:"_magic"`).Get("_gofix") != "_magic" {
f.Warnf(field.Pos(), "struct field tag %s not compatible with reflect.StructTag.Get", field.Tag.Value)
return
}
}
// checkCallExpr checks a call expression.
func (f *File) checkCallExpr(call *ast.CallExpr) {
// walkCallExpr walks a call expression.
func (f *File) walkCallExpr(call *ast.CallExpr) {
switch x := call.Fun.(type) {
case *ast.Ident:
f.checkCall(call, x.Name)
f.walkCall(call, x.Name)
case *ast.SelectorExpr:
f.checkCall(call, x.Sel.Name)
}
}
// printfList records the formatted-print functions. The value is the location
// of the format parameter. Names are lower-cased so the lookup is
// case insensitive.
var printfList = map[string]int{
"errorf": 0,
"fatalf": 0,
"fprintf": 1,
"panicf": 0,
"printf": 0,
"sprintf": 0,
}
// printList records the unformatted-print functions. The value is the location
// of the first parameter to be printed. Names are lower-cased so the lookup is
// case insensitive.
var printList = map[string]int{
"error": 0,
"fatal": 0,
"fprint": 1, "fprintln": 1,
"panic": 0, "panicln": 0,
"print": 0, "println": 0,
"sprint": 0, "sprintln": 0,
}
// checkCall triggers the print-specific checks if the call invokes a print function.
func (f *File) checkCall(call *ast.CallExpr, Name string) {
name := strings.ToLower(Name)
if skip, ok := printfList[name]; ok {
f.checkPrintf(call, Name, skip)
return
}
if skip, ok := printList[name]; ok {
f.checkPrint(call, Name, skip)
return
}
}
// checkPrintf checks a call to a formatted print routine such as Printf.
// The skip argument records how many arguments to ignore; that is,
// call.Args[skip] is (well, should be) the format argument.
func (f *File) checkPrintf(call *ast.CallExpr, name string, skip int) {
if len(call.Args) <= skip {
return
}
// Common case: literal is first argument.
arg := call.Args[skip]
lit, ok := arg.(*ast.BasicLit)
if !ok {
// Too hard to check.
if *verbose {
f.Warn(call.Pos(), "can't check args for call to", name)
}
return
}
if lit.Kind == token.STRING {
if !strings.Contains(lit.Value, "%") {
if len(call.Args) > skip+1 {
f.Badf(call.Pos(), "no formatting directive in %s call", name)
}
return
}
}
// Hard part: check formats against args.
// Trivial but useful test: count.
numArgs := 0
for i, w := 0, 0; i < len(lit.Value); i += w {
w = 1
if lit.Value[i] == '%' {
nbytes, nargs := parsePrintfVerb(lit.Value[i:])
w = nbytes
numArgs += nargs
}
}
expect := len(call.Args) - (skip + 1)
if numArgs != expect {
f.Badf(call.Pos(), "wrong number of args in %s call: %d needed but %d args", name, numArgs, expect)
}
}
// parsePrintfVerb returns the number of bytes and number of arguments
// consumed by the Printf directive that begins s, including its percent sign
// and verb.
func parsePrintfVerb(s string) (nbytes, nargs int) {
// There's guaranteed a percent sign.
nbytes = 1
end := len(s)
// There may be flags.
FlagLoop:
for nbytes < end {
switch s[nbytes] {
case '#', '0', '+', '-', ' ':
nbytes++
default:
break FlagLoop
}
}
getNum := func() {
if nbytes < end && s[nbytes] == '*' {
nbytes++
nargs++
} else {
for nbytes < end && '0' <= s[nbytes] && s[nbytes] <= '9' {
nbytes++
}
}
}
// There may be a width.
getNum()
// If there's a period, there may be a precision.
if nbytes < end && s[nbytes] == '.' {
nbytes++
getNum()
}
// Now a verb.
c, w := utf8.DecodeRuneInString(s[nbytes:])
nbytes += w
if c != '%' {
nargs++
}
return
}
// checkPrint checks a call to an unformatted print routine such as Println.
// The skip argument records how many arguments to ignore; that is,
// call.Args[skip] is the first argument to be printed.
func (f *File) checkPrint(call *ast.CallExpr, name string, skip int) {
isLn := strings.HasSuffix(name, "ln")
args := call.Args
if len(args) <= skip {
if *verbose && !isLn {
f.Badf(call.Pos(), "no args in %s call", name)
}
return
}
arg := args[skip]
if lit, ok := arg.(*ast.BasicLit); ok && lit.Kind == token.STRING {
if strings.Contains(lit.Value, "%") {
f.Badf(call.Pos(), "possible formatting directive in %s call", name)
}
f.walkCall(call, x.Sel.Name)
}
if isLn {
// The last item, if a string, should not have a newline.
arg = args[len(call.Args)-1]
if lit, ok := arg.(*ast.BasicLit); ok && lit.Kind == token.STRING {
if strings.HasSuffix(lit.Value, `\n"`) {
f.Badf(call.Pos(), "%s call ends with newline", name)
}
}
}
}
// This function never executes, but it serves as a simple test for the program.
// Test with make test.
func BadFunctionUsedInTests() {
fmt.Println() // not an error
fmt.Println("%s", "hi") // ERROR "possible formatting directive in Println call"
fmt.Printf("%s", "hi", 3) // ERROR "wrong number of args in Printf call"
fmt.Printf("%s%%%d", "hi", 3) // correct
fmt.Printf("%.*d", 3, 3) // correct
fmt.Printf("%.*d", 3, 3, 3) // ERROR "wrong number of args in Printf call"
printf("now is the time", "buddy") // ERROR "no formatting directive"
Printf("now is the time", "buddy") // ERROR "no formatting directive"
Printf("hi") // ok
f := new(File)
f.Warn(0, "%s", "hello", 3) // ERROR "possible formatting directive in Warn call"
f.Warnf(0, "%s", "hello", 3) // ERROR "wrong number of args in Warnf call"
}
type BadTypeUsedInTests struct {
X int "hello" // ERROR "struct field tag"
}
func (t *BadTypeUsedInTests) Scan(x fmt.ScanState, c byte) { // ERROR "method Scan[(]x fmt.ScanState, c byte[)] should have signature Scan[(]fmt.ScanState, rune[)] error"
}
type BadInterfaceUsedInTests interface {
ReadByte() byte // ERROR "method ReadByte[(][)] byte should have signature ReadByte[(][)] [(]byte, error[)]"
}
// printf is used by the test.
func printf(format string, args ...interface{}) {
panic("don't call - testing only")
}
src/cmd/govet/method.go 0 → 100644
View file @ b618f326
// 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.
// This file contains the code to check canonical methods.
package main
import (
"fmt"
"go/ast"
"go/printer"
"strings"
)
type MethodSig struct {
args []string
results []string
}
// canonicalMethods lists the input and output types for Go methods
// that are checked using dynamic interface checks. Because the
// checks are dynamic, such methods would not cause a compile error
// if they have the wrong signature: instead the dynamic check would
// fail, sometimes mysteriously. If a method is found with a name listed
// here but not the input/output types listed here, govet complains.
//
// A few of the canonical methods have very common names.
// For example, a type might implement a Scan method that
// has nothing to do with fmt.Scanner, but we still want to check
// the methods that are intended to implement fmt.Scanner.
// To do that, the arguments that have a + prefix are treated as
// signals that the canonical meaning is intended: if a Scan
// method doesn't have a fmt.ScanState as its first argument,
// we let it go. But if it does have a fmt.ScanState, then the
// rest has to match.
var canonicalMethods = map[string]MethodSig{
// "Flush": {{}, {"error"}}, // http.Flusher and jpeg.writer conflict
"Format": {[]string{"=fmt.State", "rune"}, []string{}}, // fmt.Formatter
"GobDecode": {[]string{"[]byte"}, []string{"error"}}, // gob.GobDecoder
"GobEncode": {[]string{}, []string{"[]byte", "error"}}, // gob.GobEncoder
"MarshalJSON": {[]string{}, []string{"[]byte", "error"}}, // json.Marshaler
"MarshalXML": {[]string{}, []string{"[]byte", "error"}}, // xml.Marshaler
"Peek": {[]string{"=int"}, []string{"[]byte", "error"}}, // image.reader (matching bufio.Reader)
"ReadByte": {[]string{}, []string{"byte", "error"}}, // io.ByteReader
"ReadFrom": {[]string{"=io.Reader"}, []string{"int64", "error"}}, // io.ReaderFrom
"ReadRune": {[]string{}, []string{"rune", "int", "error"}}, // io.RuneReader
"Scan": {[]string{"=fmt.ScanState", "rune"}, []string{"error"}}, // fmt.Scanner
"Seek": {[]string{"=int64", "int"}, []string{"int64", "error"}}, // io.Seeker
"UnmarshalJSON": {[]string{"[]byte"}, []string{"error"}}, // json.Unmarshaler
"UnreadByte": {[]string{}, []string{"error"}},
"UnreadRune": {[]string{}, []string{"error"}},
"WriteByte": {[]string{"byte"}, []string{"error"}}, // jpeg.writer (matching bufio.Writer)
"WriteTo": {[]string{"=io.Writer"}, []string{"int64", "error"}}, // io.WriterTo
}
func (f *File) checkCanonicalMethod(id *ast.Ident, t *ast.FuncType) {
// Expected input/output.
expect, ok := canonicalMethods[id.Name]
if !ok {
return
}
// Actual input/output
args := typeFlatten(t.Params.List)
var results []ast.Expr
if t.Results != nil {
results = typeFlatten(t.Results.List)
}
// Do the =s (if any) all match?
if !f.matchParams(expect.args, args, "=") || !f.matchParams(expect.results, results, "=") {
return
}
// Everything must match.
if !f.matchParams(expect.args, args, "") || !f.matchParams(expect.results, results, "") {
expectFmt := id.Name + "(" + argjoin(expect.args) + ")"
if len(expect.results) == 1 {
expectFmt += " " + argjoin(expect.results)
} else if len(expect.results) > 1 {
expectFmt += " (" + argjoin(expect.results) + ")"
}
f.b.Reset()
if err := printer.Fprint(&f.b, f.fset, t); err != nil {
fmt.Fprintf(&f.b, "<%s>", err)
}
actual := f.b.String()
if strings.HasPrefix(actual, "func(") {
actual = actual[4:]
}
actual = id.Name + actual
f.Warnf(id.Pos(), "method %s should have signature %s", actual, expectFmt)
}
}
func argjoin(x []string) string {
y := make([]string, len(x))
for i, s := range x {
if s[0] == '=' {
s = s[1:]
}
y[i] = s
}
return strings.Join(y, ", ")
}
// Turn parameter list into slice of types
// (in the ast, types are Exprs).
// Have to handle f(int, bool) and f(x, y, z int)
// so not a simple 1-to-1 conversion.
func typeFlatten(l []*ast.Field) []ast.Expr {
var t []ast.Expr
for _, f := range l {
if len(f.Names) == 0 {
t = append(t, f.Type)
continue
}
for _ = range f.Names {
t = append(t, f.Type)
}
}
return t
}
// Does each type in expect with the given prefix match the corresponding type in actual?
func (f *File) matchParams(expect []string, actual []ast.Expr, prefix string) bool {
for i, x := range expect {
if !strings.HasPrefix(x, prefix) {
continue
}
if i >= len(actual) {
return false
}
if !f.matchParamType(x, actual[i]) {
return false
}
}
if prefix == "" && len(actual) > len(expect) {
return false
}
return true
}
// Does this one type match?
func (f *File) matchParamType(expect string, actual ast.Expr) bool {
if strings.HasPrefix(expect, "=") {
expect = expect[1:]
}
// Strip package name if we're in that package.
if n := len(f.file.Name.Name); len(expect) > n && expect[:n] == f.file.Name.Name && expect[n] == '.' {
expect = expect[n+1:]
}
// Overkill but easy.
f.b.Reset()
printer.Fprint(&f.b, f.fset, actual)
return f.b.String() == expect
}
src/cmd/govet/print.go 0 → 100644
View file @ b618f326
// 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.
// This file contains the printf-checker.
package main
import (
"flag"
"fmt"
"go/ast"
"go/token"
"strings"
"unicode/utf8"
)
var printfuncs = flag.String("printfuncs", "", "comma-separated list of print function names to check")
// printfList records the formatted-print functions. The value is the location
// of the format parameter. Names are lower-cased so the lookup is
// case insensitive.
var printfList = map[string]int{
"errorf": 0,
"fatalf": 0,
"fprintf": 1,
"panicf": 0,
"printf": 0,
"sprintf": 0,
}
// printList records the unformatted-print functions. The value is the location
// of the first parameter to be printed. Names are lower-cased so the lookup is
// case insensitive.
var printList = map[string]int{
"error": 0,
"fatal": 0,
"fprint": 1, "fprintln": 1,
"panic": 0, "panicln": 0,
"print": 0, "println": 0,
"sprint": 0, "sprintln": 0,
}
// checkCall triggers the print-specific checks if the call invokes a print function.
func (f *File) checkFmtPrintfCall(call *ast.CallExpr, Name string) {
name := strings.ToLower(Name)
if skip, ok := printfList[name]; ok {
f.checkPrintf(call, Name, skip)
return
}
if skip, ok := printList[name]; ok {
f.checkPrint(call, Name, skip)
return
}
}
// checkPrintf checks a call to a formatted print routine such as Printf.
// The skip argument records how many arguments to ignore; that is,
// call.Args[skip] is (well, should be) the format argument.
func (f *File) checkPrintf(call *ast.CallExpr, name string, skip int) {
if len(call.Args) <= skip {
return
}
// Common case: literal is first argument.
arg := call.Args[skip]
lit, ok := arg.(*ast.BasicLit)
if !ok {
// Too hard to check.
if *verbose {
f.Warn(call.Pos(), "can't check args for call to", name)
}
return
}
if lit.Kind == token.STRING {
if !strings.Contains(lit.Value, "%") {
if len(call.Args) > skip+1 {
f.Badf(call.Pos(), "no formatting directive in %s call", name)
}
return
}
}
// Hard part: check formats against args.
// Trivial but useful test: count.
numArgs := 0
for i, w := 0, 0; i < len(lit.Value); i += w {
w = 1
if lit.Value[i] == '%' {
nbytes, nargs := parsePrintfVerb(lit.Value[i:])
w = nbytes
numArgs += nargs
}
}
expect := len(call.Args) - (skip + 1)
if numArgs != expect {
f.Badf(call.Pos(), "wrong number of args in %s call: %d needed but %d args", name, numArgs, expect)
}
}
// parsePrintfVerb returns the number of bytes and number of arguments
// consumed by the Printf directive that begins s, including its percent sign
// and verb.
func parsePrintfVerb(s string) (nbytes, nargs int) {
// There's guaranteed a percent sign.
nbytes = 1
end := len(s)
// There may be flags.
FlagLoop:
for nbytes < end {
switch s[nbytes] {
case '#', '0', '+', '-', ' ':
nbytes++
default:
break FlagLoop
}
}
getNum := func() {
if nbytes < end && s[nbytes] == '*' {
nbytes++
nargs++
} else {
for nbytes < end && '0' <= s[nbytes] && s[nbytes] <= '9' {
nbytes++
}
}
}
// There may be a width.
getNum()
// If there's a period, there may be a precision.
if nbytes < end && s[nbytes] == '.' {
nbytes++
getNum()
}
// Now a verb.
c, w := utf8.DecodeRuneInString(s[nbytes:])
nbytes += w
if c != '%' {
nargs++
}
return
}
// checkPrint checks a call to an unformatted print routine such as Println.
// The skip argument records how many arguments to ignore; that is,
// call.Args[skip] is the first argument to be printed.
func (f *File) checkPrint(call *ast.CallExpr, name string, skip int) {
isLn := strings.HasSuffix(name, "ln")
args := call.Args
if len(args) <= skip {
if *verbose && !isLn {
f.Badf(call.Pos(), "no args in %s call", name)
}
return
}
arg := args[skip]
if lit, ok := arg.(*ast.BasicLit); ok && lit.Kind == token.STRING {
if strings.Contains(lit.Value, "%") {
f.Badf(call.Pos(), "possible formatting directive in %s call", name)
}
}
if isLn {
// The last item, if a string, should not have a newline.
arg = args[len(call.Args)-1]
if lit, ok := arg.(*ast.BasicLit); ok && lit.Kind == token.STRING {
if strings.HasSuffix(lit.Value, `\n"`) {
f.Badf(call.Pos(), "%s call ends with newline", name)
}
}
}
}
// This function never executes, but it serves as a simple test for the program.
// Test with make test.
func BadFunctionUsedInTests() {
fmt.Println() // not an error
fmt.Println("%s", "hi") // ERROR "possible formatting directive in Println call"
fmt.Printf("%s", "hi", 3) // ERROR "wrong number of args in Printf call"
fmt.Printf("%s%%%d", "hi", 3) // correct
fmt.Printf("%.*d", 3, 3) // correct
fmt.Printf("%.*d", 3, 3, 3) // ERROR "wrong number of args in Printf call"
printf("now is the time", "buddy") // ERROR "no formatting directive"
Printf("now is the time", "buddy") // ERROR "no formatting directive"
Printf("hi") // ok
f := new(File)
f.Warn(0, "%s", "hello", 3) // ERROR "possible formatting directive in Warn call"
f.Warnf(0, "%s", "hello", 3) // ERROR "wrong number of args in Warnf call"
}
type BadTypeUsedInTests struct {
X int "hello" // ERROR "struct field tag"
}
func (t *BadTypeUsedInTests) Scan(x fmt.ScanState, c byte) { // ERROR "method Scan[(]x fmt.ScanState, c byte[)] should have signature Scan[(]fmt.ScanState, rune[)] error"
}
type BadInterfaceUsedInTests interface {
ReadByte() byte // ERROR "method ReadByte[(][)] byte should have signature ReadByte[(][)] [(]byte, error[)]"
}
// printf is used by the test.
func printf(format string, args ...interface{}) {
panic("don't call - testing only")
}
src/cmd/govet/structtag.go 0 → 100644
View file @ b618f326
// 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.
// This file contains the test for canonical struct tags.
package main
import (
"go/ast"
"reflect"
"strconv"
)
// checkField checks a struct field tag.
func (f *File) checkCanonicalFieldTag(field *ast.Field) {
if field.Tag == nil {
return
}
tag, err := strconv.Unquote(field.Tag.Value)
if err != nil {
f.Warnf(field.Pos(), "unable to read struct tag %s", field.Tag.Value)
return
}
// Check tag for validity by appending
// new key:value to end and checking that
// the tag parsing code can find it.
if reflect.StructTag(tag+` _gofix:"_magic"`).Get("_gofix") != "_magic" {
f.Warnf(field.Pos(), "struct field tag %s not compatible with reflect.StructTag.Get", field.Tag.Value)
return
}
}
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