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// Copyright 2012 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 unkeyed struct literals.
package main
import (
"flag"
"go/ast"
"strings"
"golang.org/x/tools/cmd/vet/whitelist"
)
var compositeWhiteList = flag.Bool("compositewhitelist", true, "use composite white list; for testing only")
func init() {
register("composites",
"check that composite literals used field-keyed elements",
checkUnkeyedLiteral,
compositeLit)
}
// checkUnkeyedLiteral checks if a composite literal is a struct literal with
// unkeyed fields.
func checkUnkeyedLiteral(f *File, node ast.Node) {
c := node.(*ast.CompositeLit)
typ := c.Type
for {
if typ1, ok := c.Type.(*ast.ParenExpr); ok {
typ = typ1
continue
}
break
}
switch typ.(type) {
case *ast.ArrayType:
return
case *ast.MapType:
return
case *ast.StructType:
return // a literal struct type does not need to use keys
case *ast.Ident:
// A simple type name like t or T does not need keys either,
// since it is almost certainly declared in the current package.
// (The exception is names being used via import . "pkg", but
// those are already breaking the Go 1 compatibility promise,
// so not reporting potential additional breakage seems okay.)
return
}
// Otherwise the type is a selector like pkg.Name.
// We only care if pkg.Name is a struct, not if it's a map, array, or slice.
isStruct, typeString := f.pkg.isStruct(c)
if !isStruct {
return
}
if typeString == "" { // isStruct doesn't know
typeString = f.gofmt(typ)
}
// It's a struct, or we can't tell it's not a struct because we don't have types.
// Check if the CompositeLit contains an unkeyed field.
allKeyValue := true
for _, e := range c.Elts {
if _, ok := e.(*ast.KeyValueExpr); !ok {
allKeyValue = false
break
}
}
if allKeyValue {
return
}
// Check that the CompositeLit's type has the form pkg.Typ.
s, ok := c.Type.(*ast.SelectorExpr)
if !ok {
return
}
pkg, ok := s.X.(*ast.Ident)
if !ok {
return
}
// Convert the package name to an import path, and compare to a whitelist.
path := pkgPath(f, pkg.Name)
if path == "" {
f.Badf(c.Pos(), "unresolvable package for %s.%s literal", pkg.Name, s.Sel.Name)
return
}
typeName := path + "." + s.Sel.Name
if *compositeWhiteList && whitelist.UnkeyedLiteral[typeName] {
return
}
f.Bad(c.Pos(), typeString+" composite literal uses unkeyed fields")
}
// pkgPath returns the import path "image/png" for the package name "png".
//
// This is based purely on syntax and convention, and not on the imported
// package's contents. It will be incorrect if a package name differs from the
// leaf element of the import path, or if the package was a dot import.
func pkgPath(f *File, pkgName string) (path string) {
for _, x := range f.file.Imports {
s := strings.Trim(x.Path.Value, `"`)
if x.Name != nil {
// Catch `import pkgName "foo/bar"`.
if x.Name.Name == pkgName {
return s
}
} else {
// Catch `import "pkgName"` or `import "foo/bar/pkgName"`.
if s == pkgName || strings.HasSuffix(s, "/"+pkgName) {
return s
}
}
}
return ""
}