blob: 27677139e1fd77b9785aeb825a12a1689fffc3df [file] [log] [blame]
// Copyright 2021 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.
package reflectvaluecompare
import (
_ "embed"
"go/ast"
"go/token"
"go/types"
"golang.org/x/tools/go/analysis"
"golang.org/x/tools/go/analysis/passes/inspect"
"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
"golang.org/x/tools/go/ast/inspector"
"golang.org/x/tools/go/types/typeutil"
)
//go:embed doc.go
var doc string
var Analyzer = &analysis.Analyzer{
Name: "reflectvaluecompare",
Doc: analysisutil.MustExtractDoc(doc, "reflectvaluecompare"),
URL: "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/reflectvaluecompare",
Requires: []*analysis.Analyzer{inspect.Analyzer},
Run: run,
}
func run(pass *analysis.Pass) (interface{}, error) {
inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
nodeFilter := []ast.Node{
(*ast.BinaryExpr)(nil),
(*ast.CallExpr)(nil),
}
inspect.Preorder(nodeFilter, func(n ast.Node) {
switch n := n.(type) {
case *ast.BinaryExpr:
if n.Op != token.EQL && n.Op != token.NEQ {
return
}
if isReflectValue(pass, n.X) || isReflectValue(pass, n.Y) {
if n.Op == token.EQL {
pass.ReportRangef(n, "avoid using == with reflect.Value")
} else {
pass.ReportRangef(n, "avoid using != with reflect.Value")
}
}
case *ast.CallExpr:
fn, ok := typeutil.Callee(pass.TypesInfo, n).(*types.Func)
if !ok {
return
}
if fn.FullName() == "reflect.DeepEqual" && (isReflectValue(pass, n.Args[0]) || isReflectValue(pass, n.Args[1])) {
pass.ReportRangef(n, "avoid using reflect.DeepEqual with reflect.Value")
}
}
})
return nil, nil
}
// isReflectValue reports whether the type of e is reflect.Value.
func isReflectValue(pass *analysis.Pass, e ast.Expr) bool {
tv, ok := pass.TypesInfo.Types[e]
if !ok { // no type info, something else is wrong
return false
}
// See if the type is reflect.Value
named, ok := tv.Type.(*types.Named)
if !ok {
return false
}
if obj := named.Obj(); obj == nil || obj.Pkg() == nil || obj.Pkg().Path() != "reflect" || obj.Name() != "Value" {
return false
}
if _, ok := e.(*ast.CompositeLit); ok {
// This is reflect.Value{}. Don't treat that as an error.
// Users should probably use x.IsValid() rather than x == reflect.Value{}, but the latter isn't wrong.
return false
}
return true
}