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|
package gocapturedrefrace
import (
"bytes"
"fmt"
"go/ast"
"go/printer"
"go/token"
"golang.org/x/tools/go/analysis"
)
var Analyzer = &analysis.Analyzer{
Name: "gocapturedrefrace",
Doc: "reports captured references in goroutine closures",
Run: run,
}
func run(pass *analysis.Pass) (interface{}, error) {
for _, file := range pass.Files {
ast.Inspect(
file,
func(node ast.Node) bool {
goStmt, ok := node.(*ast.GoStmt)
if !ok {
return true
}
var printedNode bytes.Buffer
err := printer.Fprint(&printedNode, pass.Fset, goStmt)
if err != nil {
panic(err)
}
fmt.Printf("%#v\n", goStmt)
// TODO: Get func literal of go statement
// TODO: Get variables in func literal
funcLit, ok := goStmt.Call.Fun.(*ast.FuncLit)
if !ok {
return true
}
checkClosure(pass, funcLit)
return true
},
)
}
return nil, nil
}
func checkClosure(pass *analysis.Pass, funcLit *ast.FuncLit) {
formalParams := []*ast.Object{}
for _, field := range funcLit.Type.Params.List {
formalParams = append(formalParams, field.Names[0].Obj)
}
fmt.Printf("formalParams: %#v\n", formalParams)
// TODO: Ensure argument types are not references
// TODO: Build a list of variables created in the closure
assignments := assignmentsInFunc(pass, funcLit)
fmt.Printf("variable declarations: %#v\n", assignments)
// TODO: Use ast.GenDecl instead
ast.Inspect(
funcLit,
func(node ast.Node) bool {
ident, ok := node.(*ast.Ident)
if !ok {
return true
}
if ident.Obj == nil {
return true
}
// TODO: Find out whether ident is a captured reference
// Maybe check if variable was not assigned or passed as an argument?
for _, param := range formalParams {
if ident.Obj == param {
return true
}
}
pass.Reportf(
ident.Pos(),
"variable found %q",
ident,
)
return true
},
)
}
func assignmentsInFunc(
pass *analysis.Pass,
funcLit *ast.FuncLit,
) []*ast.Object {
assignments := []*ast.Object{}
ast.Inspect(
funcLit,
func(node ast.Node) bool {
decl, ok := node.(*ast.GenDecl)
if !ok {
return true
}
fmt.Printf("decl: %#v\n", decl)
if decl.Tok != token.VAR {
return true
}
for _, spec := range decl.Specs {
valueSpec, ok := spec.(*ast.ValueSpec)
if !ok {
return true
}
fmt.Printf("valueSpec: %#v\n", valueSpec)
assignments = append(assignments, valueSpec.Names[0].Obj)
}
// ident, ok := node.(*ast.Ident)
// if !ok {
// return true
// }
//
// if ident.Obj == nil || ident.Obj.Decl == nil {
// return true
// }
//
// _, ok = ident.Obj.Decl.(*ast.AssignStmt)
// if !ok {
// return true
// }
//
// assignments = append(assignments, ident.Name)
return true
},
)
return assignments
}
|
