| // Copyright 2022 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 timeformat defines an Analyzer that checks for the use |
| // of time.Format or time.Parse calls with a bad format. |
| package timeformat |
| |
| import ( |
| "fmt" |
| "go/ast" |
| "go/constant" |
| "go/token" |
| "go/types" |
| "strings" |
| |
| "golang.org/x/tools/go/analysis" |
| "golang.org/x/tools/go/analysis/passes/inspect" |
| "golang.org/x/tools/go/ast/inspector" |
| "golang.org/x/tools/go/types/typeutil" |
| ) |
| |
| const badFormat = "2006-02-01" |
| const goodFormat = "2006-01-02" |
| |
| const Doc = `check for calls of (time.Time).Format or time.Parse with 2006-02-01 |
| |
| The timeformat checker looks for time formats with the 2006-02-01 (yyyy-dd-mm) |
| format. Internationally, "yyyy-dd-mm" does not occur in common calendar date |
| standards, and so it is more likely that 2006-01-02 (yyyy-mm-dd) was intended. |
| ` |
| |
| var Analyzer = &analysis.Analyzer{ |
| Name: "timeformat", |
| Doc: Doc, |
| 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.CallExpr)(nil), |
| } |
| inspect.Preorder(nodeFilter, func(n ast.Node) { |
| call := n.(*ast.CallExpr) |
| fn, ok := typeutil.Callee(pass.TypesInfo, call).(*types.Func) |
| if !ok { |
| return |
| } |
| if !isTimeDotFormat(fn) && !isTimeDotParse(fn) { |
| return |
| } |
| if len(call.Args) > 0 { |
| arg := call.Args[0] |
| badAt := badFormatAt(pass.TypesInfo, arg) |
| |
| if badAt > -1 { |
| // Check if it's a literal string, otherwise we can't suggest a fix. |
| if _, ok := arg.(*ast.BasicLit); ok { |
| fmt.Printf("%#v\n", arg) |
| pos := int(arg.Pos()) + badAt + 1 // +1 to skip the " or ` |
| end := pos + len(badFormat) |
| |
| pass.Report(analysis.Diagnostic{ |
| Pos: token.Pos(pos), |
| End: token.Pos(end), |
| Message: badFormat + " should be " + goodFormat, |
| SuggestedFixes: []analysis.SuggestedFix{{ |
| Message: "Replace " + badFormat + " with " + goodFormat, |
| TextEdits: []analysis.TextEdit{{ |
| Pos: token.Pos(pos), |
| End: token.Pos(end), |
| NewText: []byte(goodFormat), |
| }}, |
| }}, |
| }) |
| } else { |
| pass.Reportf(arg.Pos(), badFormat+" should be "+goodFormat) |
| } |
| } |
| } |
| }) |
| return nil, nil |
| } |
| |
| func isTimeDotFormat(f *types.Func) bool { |
| if f.Name() != "Format" || f.Pkg().Path() != "time" { |
| return false |
| } |
| sig, ok := f.Type().(*types.Signature) |
| if !ok { |
| return false |
| } |
| // Verify that the receiver is time.Time. |
| recv := sig.Recv() |
| if recv == nil { |
| return false |
| } |
| named, ok := recv.Type().(*types.Named) |
| return ok && named.Obj().Name() == "Time" |
| } |
| |
| func isTimeDotParse(f *types.Func) bool { |
| if f.Name() != "Parse" || f.Pkg().Path() != "time" { |
| return false |
| } |
| // Verify that there is no receiver. |
| sig, ok := f.Type().(*types.Signature) |
| return ok && sig.Recv() == nil |
| } |
| |
| // badFormatAt return the start of a bad format in e or -1 if no bad format is found. |
| func badFormatAt(info *types.Info, e ast.Expr) int { |
| tv, ok := info.Types[e] |
| if !ok { // no type info, assume good |
| return -1 |
| } |
| |
| t, ok := tv.Type.(*types.Basic) |
| if !ok || t.Info()&types.IsString == 0 { |
| return -1 |
| } |
| |
| if tv.Value == nil { |
| return -1 |
| } |
| |
| return strings.Index(constant.StringVal(tv.Value), badFormat) |
| } |