cmd/vet: provide flags to control which tests to run

By default, all are still run, but a particular test can be
selected with the new flags.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/6395053

src/cmd/vet/doc.go

@@ -9,9 +9,12 @@ 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.
 
+By default all checks are performed, but if explicit flags are provided, only
+those identified by the flags are performed.
+
 Available checks:
 
-1. Printf family
+1. Printf family, flag -printf
 
 Suspicious calls to functions in the Printf family, including any functions
 with these names:
@@ -28,7 +31,7 @@ complains about arguments that look like format descriptor strings.
 It also checks for errors such as using a Writer as the first argument of
 Printf.
 
-2. Methods
+2. Methods, flag -methods
 
 Non-standard signatures for methods with familiar names, including:
 	Format GobEncode GobDecode MarshalJSON MarshalXML
@@ -36,16 +39,21 @@ Non-standard signatures for methods with familiar names, including:
 	UnmarshalJSON UnreadByte UnreadRune WriteByte
 	WriteTo
 
-3. Struct tags
+3. Struct tags, flag -structtags
 
 Struct tags that do not follow the format understood by reflect.StructTag.Get.
 
+4. Untagged composite literals, flag -composites
+
+Composite struct literals that do not used the type-tagged syntax.
+
+
 Usage:
 
 	go tool vet [flag] [file.go ...]
 	go tool vet [flag] [directory ...] # Scan all .go files under directory, recursively
 
-The flags are:
+The other flags are:
 	-v
 		Verbose mode
 	-printfuncs

src/cmd/vet/main.go

@@ -23,6 +23,15 @@ import (
 var verbose = flag.Bool("v", false, "verbose")
 var exitCode = 0
 
+// Flags to control which checks to perform
+var (
+	vetAll             = flag.Bool("all", true, "check everything; disabled if any explicit check is requested")
+	vetMethods         = flag.Bool("methods", false, "check that canonically named methods are canonically defined")
+	vetPrintf          = flag.Bool("printf", false, "check printf-like invocations")
+	vetStructTags      = flag.Bool("structtags", false, "check that struct field tags have canonical format")
+	vetUntaggedLiteral = flag.Bool("composites", false, "check that composite literals used type-tagged elements")
+)
+
 // setExit sets the value for os.Exit when it is called, later.  It
 // remembers the highest value.
 func setExit(err int) {
@@ -50,6 +59,11 @@ func main() {
 	flag.Usage = Usage
 	flag.Parse()
 
+	// If a check is named explicitly, turn off the 'all' flag.
+	if *vetMethods || *vetPrintf || *vetStructTags || *vetUntaggedLiteral {
+		*vetAll = false
+	}
+
 	if *printfuncs != "" {
 		for _, name := range strings.Split(*printfuncs, ",") {
 			if len(name) == 0 {

src/cmd/vet/method.go

@@ -55,6 +55,9 @@ var canonicalMethods = map[string]MethodSig{
 }
 
 func (f *File) checkCanonicalMethod(id *ast.Ident, t *ast.FuncType) {
+	if !*vetMethods && !*vetAll {
+		return
+	}
 	// Expected input/output.
 	expect, ok := canonicalMethods[id.Name]
 	if !ok {
@@ -159,3 +162,10 @@ func (f *File) matchParamType(expect string, actual ast.Expr) bool {
 	printer.Fprint(&f.b, f.fset, actual)
 	return f.b.String() == expect
 }
+
+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[)]"
+}

src/cmd/vet/print.go

@@ -43,6 +43,9 @@ var printList = map[string]int{
 
 // checkCall triggers the print-specific checks if the call invokes a print function.
 func (f *File) checkFmtPrintfCall(call *ast.CallExpr, Name string) {
+	if !*vetPrintf && !*vetAll {
+		return
+	}
 	name := strings.ToLower(Name)
 	if skip, ok := printfList[name]; ok {
 		f.checkPrintf(call, Name, skip)
@@ -290,17 +293,6 @@ func BadFunctionUsedInTests() {
 	f.Warnf(0, "%#s", "hello")   // ERROR "unrecognized printf flag"
 }
 
-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/vet/structtag.go

@@ -14,6 +14,9 @@ import (
 
 // checkField checks a struct field tag.
 func (f *File) checkCanonicalFieldTag(field *ast.Field) {
+	if !*vetStructTags && !*vetAll {
+		return
+	}
 	if field.Tag == nil {
 		return
 	}
@@ -32,3 +35,7 @@ func (f *File) checkCanonicalFieldTag(field *ast.Field) {
 		return
 	}
 }
+
+type BadTypeUsedInTests struct {
+	X int "hello" // ERROR "struct field tag"
+}

src/cmd/vet/taglit.go

@@ -14,6 +14,9 @@ import (
 // checkUntaggedLiteral checks if a composite literal is an struct literal with
 // untagged fields.
 func (f *File) checkUntaggedLiteral(c *ast.CompositeLit) {
+	if !*vetUntaggedLiteral && !*vetAll {
+		return
+	}
 	// Check if the CompositeLit contains an untagged field.
 	allKeyValue := true
 	for _, e := range c.Elts {
@@ -119,3 +122,7 @@ var untaggedLiteralWhitelist = map[string]bool{
 	"image.Point":         true,
 	"image.Rectangle":     true,
 }
+
+type BadTag struct {
+	S string `this is a bad tag`
+}