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|
// TODO: doc
package defererr
import (
"fmt"
"go/ast"
"go/token"
"go/types"
"golang.org/x/tools/go/analysis"
)
var Analyzer = &analysis.Analyzer{
Name: "defererr",
Doc: "reports issues returning errors from defer",
Run: run,
}
func run(pass *analysis.Pass) (interface{}, error) {
// TODO: Find defer closure
// Does it set error defined in outer scope?
// Does outer scope declare error variable in signature?
// Is err variable returned after closure?
for _, file := range pass.Files {
ast.Inspect(
file,
func(node ast.Node) bool {
funcDecl, ok := node.(*ast.FuncDecl)
if !ok {
return true
}
if funcDecl.Type.Results == nil {
return true
}
funcReturnsError := false
errorReturnIndex := -1
for i, returnVal := range funcDecl.Type.Results.List {
fmt.Printf("returnVal Type: %#v\n", returnVal.Type)
returnIdent, ok := returnVal.Type.(*ast.Ident)
if !ok {
return true
}
if returnIdent.Name == "error" {
funcReturnsError = true
errorReturnIndex = i
}
}
// Can we do the same for non-error types?
// for _, returnVal := range funcType.Results.List {
// }
if !funcReturnsError || errorReturnIndex == -1 {
return true
}
if len(funcDecl.Type.Results.List[errorReturnIndex].Names) > 0 {
fmt.Printf("return error var name: %#v\n", funcDecl.Type.Results.List[errorReturnIndex].Names[0])
}
errorReturnField := funcDecl.Type.Results.List[errorReturnIndex]
ast.Inspect(
funcDecl.Body,
func(node ast.Node) bool {
// fmt.Printf("node: %#v\n", node)
deferStmt, ok := node.(*ast.DeferStmt)
if !ok {
return true
}
fmt.Printf("defer: %#v\n", deferStmt)
// TODO: Find out if defer uses assigns an error variable without declaring it
funcLit, ok := deferStmt.Call.Fun.(*ast.FuncLit)
if !ok {
return true
}
ast.Inspect(
funcLit.Body,
func(node ast.Node) bool {
assignStmt, ok := node.(*ast.AssignStmt)
if !ok {
return true
}
if assignStmt.Tok == token.DEFINE {
return true
}
fmt.Printf("assignStmt: %#v\n", assignStmt)
// TODO: Get type of Lhs, check if "error"
// If "error", then ensure error return is declared in signature
deferAssignsError := false
for _, variable := range assignStmt.Lhs {
ident, ok := variable.(*ast.Ident)
if !ok {
continue
}
obj := pass.TypesInfo.Defs[ident]
valueSpec, ok := ident.Obj.Decl.(*ast.ValueSpec)
if !ok {
continue
}
fmt.Printf("variable: %#v\n", ident)
fmt.Printf("variable.obj: %#v\n", ident.Obj)
fmt.Printf("variable.obj.type: %#v\n", ident.Obj.Type)
fmt.Printf("variable.obj.valuespec: %#v\n", valueSpec)
fmt.Printf("variable.obj.valuespec.type: %#v\n", valueSpec.Type)
fmt.Printf("obj: %#v\n", obj)
t := pass.TypesInfo.Types[variable]
fmt.Printf("type: %#v\n", t)
fmt.Printf("type.type: %#v\n", t.Type)
named, ok := t.Type.(*types.Named)
if !ok {
continue
}
fmt.Printf("type.type.obj: %#v\n", named.Obj())
fmt.Printf("type.type.obj: %#v\n", named.Obj().Name())
if named.Obj().Name() == "error" {
deferAssignsError = true
isErrorNameInReturnSignature := false
for _, errorReturnIdent := range errorReturnField.Names {
if ident.Name == errorReturnIdent.Name {
// Report if no matches
isErrorNameInReturnSignature = true
}
}
if !isErrorNameInReturnSignature {
pass.Reportf(
errorReturnField.Pos(),
"return signature should be '(err error)'", // TODO: Use name from ident.Name
// errorReturnField,
)
break
}
}
}
if !deferAssignsError {
return true
}
// TODO: Check that funcDecl declares error in signature (check before ast.Inspect on function body, report here)
// isErrorNameInReturnSignature := false
//
// for _, errorReturnIdent := range errorReturnField.Names {
// if ident.Name == errorReturnIdent.Name {
// // Report if no matches
// isErrorNameInReturnSignature = true
// }
// }
//
// if !isErrorNameInReturnSignature {
// pass.Reportf(
// errorReturnField.Pos(),
// "return signature should be '(err error)' (TODO)",
// errorReturnField,
// )
// }
return true
},
)
return true
},
)
// // Look for a function literal after the `defer` statement.
// funcLit, ok := deferStmt.Call.Fun.(*ast.FuncLit)
// if !ok {
// return true
// }
//
// funcScope := pass.TypesInfo.Scopes[funcLit.Type]
//
// // Try to find the function where the defer is defined. Note, defer can be defined in an inner block.
// funcType, ok := funcScope.Parent().(*ast.FuncType)
// if !ok {
// return true
// }
// fmt.Printf("func: %#v\n", funcType)
//
// if funcLit.Type.Results == nil {
// return true
// }
//
// for _, returnVal := range funcLit.Type.Results.List {
// fmt.Printf("returnVal: %#v\n", returnVal)
// }
fmt.Println()
return true
},
)
}
return nil, nil
}
|
