| 1 | // Copyright 2022 The Go Authors. All rights reserved. |
|---|---|
| 2 | // Use of this source code is governed by a BSD-style |
| 3 | // license that can be found in the LICENSE file. |
| 4 | |
| 5 | // Package timeformat defines an Analyzer that checks for the use |
| 6 | // of time.Format or time.Parse calls with a bad format. |
| 7 | package timeformat |
| 8 | |
| 9 | import ( |
| 10 | "go/ast" |
| 11 | "go/constant" |
| 12 | "go/token" |
| 13 | "go/types" |
| 14 | "strings" |
| 15 | |
| 16 | "golang.org/x/tools/go/analysis" |
| 17 | "golang.org/x/tools/go/analysis/passes/inspect" |
| 18 | "golang.org/x/tools/go/ast/inspector" |
| 19 | "golang.org/x/tools/go/types/typeutil" |
| 20 | ) |
| 21 | |
| 22 | const badFormat = "2006-02-01" |
| 23 | const goodFormat = "2006-01-02" |
| 24 | |
| 25 | const Doc = `check for calls of (time.Time).Format or time.Parse with 2006-02-01 |
| 26 | |
| 27 | The timeformat checker looks for time formats with the 2006-02-01 (yyyy-dd-mm) |
| 28 | format. Internationally, "yyyy-dd-mm" does not occur in common calendar date |
| 29 | standards, and so it is more likely that 2006-01-02 (yyyy-mm-dd) was intended. |
| 30 | ` |
| 31 | |
| 32 | var Analyzer = &analysis.Analyzer{ |
| 33 | Name: "timeformat", |
| 34 | Doc: Doc, |
| 35 | Requires: []*analysis.Analyzer{inspect.Analyzer}, |
| 36 | Run: run, |
| 37 | } |
| 38 | |
| 39 | func run(pass *analysis.Pass) (interface{}, error) { |
| 40 | inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector) |
| 41 | |
| 42 | nodeFilter := []ast.Node{ |
| 43 | (*ast.CallExpr)(nil), |
| 44 | } |
| 45 | inspect.Preorder(nodeFilter, func(n ast.Node) { |
| 46 | call := n.(*ast.CallExpr) |
| 47 | fn, ok := typeutil.Callee(pass.TypesInfo, call).(*types.Func) |
| 48 | if !ok { |
| 49 | return |
| 50 | } |
| 51 | if !isTimeDotFormat(fn) && !isTimeDotParse(fn) { |
| 52 | return |
| 53 | } |
| 54 | if len(call.Args) > 0 { |
| 55 | arg := call.Args[0] |
| 56 | badAt := badFormatAt(pass.TypesInfo, arg) |
| 57 | |
| 58 | if badAt > -1 { |
| 59 | // Check if it's a literal string, otherwise we can't suggest a fix. |
| 60 | if _, ok := arg.(*ast.BasicLit); ok { |
| 61 | pos := int(arg.Pos()) + badAt + 1 // +1 to skip the " or ` |
| 62 | end := pos + len(badFormat) |
| 63 | |
| 64 | pass.Report(analysis.Diagnostic{ |
| 65 | Pos: token.Pos(pos), |
| 66 | End: token.Pos(end), |
| 67 | Message: badFormat + " should be " + goodFormat, |
| 68 | SuggestedFixes: []analysis.SuggestedFix{{ |
| 69 | Message: "Replace " + badFormat + " with " + goodFormat, |
| 70 | TextEdits: []analysis.TextEdit{{ |
| 71 | Pos: token.Pos(pos), |
| 72 | End: token.Pos(end), |
| 73 | NewText: []byte(goodFormat), |
| 74 | }}, |
| 75 | }}, |
| 76 | }) |
| 77 | } else { |
| 78 | pass.Reportf(arg.Pos(), badFormat+" should be "+goodFormat) |
| 79 | } |
| 80 | } |
| 81 | } |
| 82 | }) |
| 83 | return nil, nil |
| 84 | } |
| 85 | |
| 86 | func isTimeDotFormat(f *types.Func) bool { |
| 87 | if f.Name() != "Format" || f.Pkg().Path() != "time" { |
| 88 | return false |
| 89 | } |
| 90 | sig, ok := f.Type().(*types.Signature) |
| 91 | if !ok { |
| 92 | return false |
| 93 | } |
| 94 | // Verify that the receiver is time.Time. |
| 95 | recv := sig.Recv() |
| 96 | if recv == nil { |
| 97 | return false |
| 98 | } |
| 99 | named, ok := recv.Type().(*types.Named) |
| 100 | return ok && named.Obj().Name() == "Time" |
| 101 | } |
| 102 | |
| 103 | func isTimeDotParse(f *types.Func) bool { |
| 104 | if f.Name() != "Parse" || f.Pkg().Path() != "time" { |
| 105 | return false |
| 106 | } |
| 107 | // Verify that there is no receiver. |
| 108 | sig, ok := f.Type().(*types.Signature) |
| 109 | return ok && sig.Recv() == nil |
| 110 | } |
| 111 | |
| 112 | // badFormatAt return the start of a bad format in e or -1 if no bad format is found. |
| 113 | func badFormatAt(info *types.Info, e ast.Expr) int { |
| 114 | tv, ok := info.Types[e] |
| 115 | if !ok { // no type info, assume good |
| 116 | return -1 |
| 117 | } |
| 118 | |
| 119 | t, ok := tv.Type.(*types.Basic) |
| 120 | if !ok || t.Info()&types.IsString == 0 { |
| 121 | return -1 |
| 122 | } |
| 123 | |
| 124 | if tv.Value == nil { |
| 125 | return -1 |
| 126 | } |
| 127 | |
| 128 | return strings.Index(constant.StringVal(tv.Value), badFormat) |
| 129 | } |
| 130 |
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