109 lines
2.8 KiB
Go
109 lines
2.8 KiB
Go
// Copyright 2012 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package composite defines an Analyzer that checks for unkeyed
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// composite literals.
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package composite
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import (
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"go/ast"
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"go/types"
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"strings"
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"golang.org/x/tools/go/analysis"
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"golang.org/x/tools/go/analysis/passes/inspect"
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"golang.org/x/tools/go/ast/inspector"
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)
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const Doc = `checked for unkeyed composite literals
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This analyzer reports a diagnostic for composite literals of struct
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types imported from another package that do not use the field-keyed
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syntax. Such literals are fragile because the addition of a new field
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(even if unexported) to the struct will cause compilation to fail.`
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var Analyzer = &analysis.Analyzer{
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Name: "composites",
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Doc: Doc,
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Requires: []*analysis.Analyzer{inspect.Analyzer},
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RunDespiteErrors: true,
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Run: run,
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}
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var whitelist = true
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func init() {
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Analyzer.Flags.BoolVar(&whitelist, "whitelist", whitelist, "use composite white list; for testing only")
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}
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// runUnkeyedLiteral checks if a composite literal is a struct literal with
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// unkeyed fields.
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func run(pass *analysis.Pass) (interface{}, error) {
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inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
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nodeFilter := []ast.Node{
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(*ast.CompositeLit)(nil),
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}
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inspect.Preorder(nodeFilter, func(n ast.Node) {
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cl := n.(*ast.CompositeLit)
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typ := pass.TypesInfo.Types[cl].Type
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if typ == nil {
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// cannot determine composite literals' type, skip it
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return
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}
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typeName := typ.String()
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if whitelist && unkeyedLiteral[typeName] {
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// skip whitelisted types
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return
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}
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under := typ.Underlying()
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for {
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ptr, ok := under.(*types.Pointer)
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if !ok {
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break
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}
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under = ptr.Elem().Underlying()
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}
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if _, ok := under.(*types.Struct); !ok {
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// skip non-struct composite literals
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return
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}
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if isLocalType(pass, typ) {
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// allow unkeyed locally defined composite literal
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return
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}
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// check if the CompositeLit contains an unkeyed field
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allKeyValue := true
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for _, e := range cl.Elts {
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if _, ok := e.(*ast.KeyValueExpr); !ok {
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allKeyValue = false
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break
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}
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}
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if allKeyValue {
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// all the composite literal fields are keyed
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return
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}
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pass.Reportf(cl.Pos(), "%s composite literal uses unkeyed fields", typeName)
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})
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return nil, nil
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}
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func isLocalType(pass *analysis.Pass, typ types.Type) bool {
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switch x := typ.(type) {
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case *types.Struct:
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// struct literals are local types
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return true
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case *types.Pointer:
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return isLocalType(pass, x.Elem())
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case *types.Named:
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// names in package foo are local to foo_test too
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return strings.TrimSuffix(x.Obj().Pkg().Path(), "_test") == strings.TrimSuffix(pass.Pkg.Path(), "_test")
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}
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return false
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}
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