93 lines
2.6 KiB
Go
93 lines
2.6 KiB
Go
// Copyright 2018 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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// The unmarshal package defines an Analyzer that checks for passing
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// non-pointer or non-interface types to unmarshal and decode functions.
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package unmarshal
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import (
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"go/ast"
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"go/types"
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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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"golang.org/x/tools/go/types/typeutil"
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)
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const doc = `report passing non-pointer or non-interface values to unmarshal
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The unmarshal analysis reports calls to functions such as json.Unmarshal
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in which the argument type is not a pointer or an interface.`
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var Analyzer = &analysis.Analyzer{
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Name: "unmarshal",
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Doc: doc,
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Requires: []*analysis.Analyzer{inspect.Analyzer},
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Run: run,
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}
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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.CallExpr)(nil),
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}
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inspect.Preorder(nodeFilter, func(n ast.Node) {
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call := n.(*ast.CallExpr)
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fn := typeutil.StaticCallee(pass.TypesInfo, call)
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if fn == nil {
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return // not a static call
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}
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// Classify the callee (without allocating memory).
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argidx := -1
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recv := fn.Type().(*types.Signature).Recv()
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if fn.Name() == "Unmarshal" && recv == nil {
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// "encoding/json".Unmarshal
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// "encoding/xml".Unmarshal
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switch fn.Pkg().Path() {
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case "encoding/json", "encoding/xml":
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argidx = 1 // func([]byte, interface{})
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}
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} else if fn.Name() == "Decode" && recv != nil {
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// (*"encoding/json".Decoder).Decode
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// (* "encoding/gob".Decoder).Decode
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// (* "encoding/xml".Decoder).Decode
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t := recv.Type()
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if ptr, ok := t.(*types.Pointer); ok {
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t = ptr.Elem()
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}
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tname := t.(*types.Named).Obj()
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if tname.Name() == "Decoder" {
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switch tname.Pkg().Path() {
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case "encoding/json", "encoding/xml", "encoding/gob":
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argidx = 0 // func(interface{})
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}
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}
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}
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if argidx < 0 {
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return // not a function we are interested in
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}
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if len(call.Args) < argidx+1 {
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return // not enough arguments, e.g. called with return values of another function
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}
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t := pass.TypesInfo.Types[call.Args[argidx]].Type
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switch t.Underlying().(type) {
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case *types.Pointer, *types.Interface:
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return
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}
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switch argidx {
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case 0:
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pass.Reportf(call.Lparen, "call of %s passes non-pointer", fn.Name())
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case 1:
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pass.Reportf(call.Lparen, "call of %s passes non-pointer as second argument", fn.Name())
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}
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})
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return nil, nil
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}
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