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|
// TODO: doc
package defererr
import (
"fmt"
"go/ast"
"go/token"
"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
for _, returnVal := range funcDecl.Type.Results.List {
fmt.Printf("returnVal: %#v\n", returnVal.Type)
returnIdent, ok := returnVal.Type.(*ast.Ident)
if !ok {
return true
}
if returnIdent.Name == "error" {
funcReturnsError = true
}
}
// Can we do the same for non-error types?
// for _, returnVal := range funcType.Results.List {
// }
if !funcReturnsError {
return true
}
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)
fmt.Printf("token: %d\n", token.DEFINE)
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)
// }
return true
},
)
}
return nil, nil
}
|
