289 lines
9.6 KiB
Go
289 lines
9.6 KiB
Go
// Copyright 2021 The Go Authors. All rights reserved.
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// This file is a modified copy of Go's encoding/json/v2/field.go
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package sa5008
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import (
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"fmt"
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"go/ast"
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"go/types"
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"io"
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"strconv"
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"strings"
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"unicode"
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"unicode/utf8"
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"honnef.co/go/tools/analysis/report"
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"honnef.co/go/tools/go/types/typeutil"
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"golang.org/x/tools/go/analysis"
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)
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func validateJSONTag(pass *analysis.Pass, field *ast.Field, tag string) {
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hasTag := tag != ""
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tagOrig := tag
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// Check whether this field is explicitly ignored.
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if tag == "-" {
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return
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}
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// Check whether this field is unexported and not embedded,
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// which Go reflection cannot mutate for the sake of serialization.
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//
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// An embedded field of an unexported type is still capable of
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// forwarding exported fields, which may be JSON serialized.
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// This technically operates on the edge of what is permissible by
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// the Go language, but the most recent decision is to permit this.
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//
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// See https://go.dev/issue/24153 and https://go.dev/issue/32772.
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anonymous := len(field.Names) == 0
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if !anonymous && !field.Names[0].IsExported() {
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// Tag options specified on an unexported field suggests user error.
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if hasTag {
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report.Report(pass, field.Tag,
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fmt.Sprintf("unexported struct field cannot have non-ignored `json:%q` tag", tag))
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}
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return
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}
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if len(tag) > 0 && !strings.HasPrefix(tag, ",") {
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// For better compatibility with v1, accept almost any unescaped name.
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n := len(tag) - len(strings.TrimLeftFunc(tag, func(r rune) bool {
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return !strings.ContainsRune(",\\'\"`", r) // reserve comma, backslash, and quotes
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}))
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name := tag[:n]
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// If the next character is not a comma, then the name is either
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// malformed (if n > 0) or a single-quoted name.
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// In either case, call consumeTagOption to handle it further.
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var err error
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if !strings.HasPrefix(tag[n:], ",") && len(name) != len(tag) {
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name, n, err = consumeTagOption(tag)
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if err != nil {
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report.Report(pass, field.Tag, fmt.Sprintf("malformed `json` tag: %v", err))
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}
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}
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if !utf8.ValidString(name) {
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report.Report(pass, field.Tag,
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fmt.Sprintf("invalid UTF-8 in JSON object name %q", name))
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name = string([]rune(name)) // replace invalid UTF-8 with utf8.RuneError
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}
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if name == "-" && tag[0] == '-' {
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// TODO(dh): offer automatic fix
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report.Report(pass, field.Tag,
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fmt.Sprintf("should encoding/json ignore this field or name it \"-\"? Either use `json:\"-\"` to ignore the field or use `json:\"'-'%s` to specify %q as the name",
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strings.TrimPrefix(strconv.Quote(tagOrig), `"-`), name))
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}
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tag = tag[n:]
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}
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// Handle any additional tag options (if any).
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var wasFormat bool
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seenOpts := make(map[string]bool)
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for len(tag) > 0 {
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// Consume comma delimiter.
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if tag[0] != ',' {
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report.Report(pass, field.Tag,
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fmt.Sprintf("malformed `json` tag: invalid character %q before next option (expecting ',')",
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tag[0]))
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} else {
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tag = tag[len(","):]
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if len(tag) == 0 {
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report.Report(pass, field.Tag, "malformed `json` tag: invalid trailing ',' character")
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break
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}
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}
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// Consume and process the tag option.
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opt, n, err := consumeTagOption(tag)
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if err != nil {
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report.Report(pass, field.Tag, fmt.Sprintf("malformed `json` tag: %v", err))
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}
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rawOpt := tag[:n]
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tag = tag[n:]
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switch {
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case wasFormat:
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report.Report(pass, field.Tag, "`format` tag option was not specified last")
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case strings.HasPrefix(rawOpt, "'") && strings.TrimFunc(opt, isLetterOrDigit) == "":
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// TODO(dh): offer automatic fix
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report.Report(pass, field.Tag,
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fmt.Sprintf("unnecessarily quoted appearance of `%s` tag option; specify `%s` instead", rawOpt, opt))
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}
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switch opt {
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case "case":
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if !strings.HasPrefix(tag, ":") {
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// TODO(dh): offer automatic fix
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report.Report(pass, field.Tag,
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"missing value for `case` tag option; specify `case:ignore` or `case:strict` instead")
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break
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}
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tag = tag[len(":"):]
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opt, n, err := consumeTagOption(tag)
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if err != nil {
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report.Report(pass, field.Tag,
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fmt.Sprintf("malformed value for `case` tag option: %v", err))
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break
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}
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rawOpt := tag[:n]
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tag = tag[n:]
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if strings.HasPrefix(rawOpt, "'") {
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// TODO(dh): offer automatic fix
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report.Report(pass, field.Tag,
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fmt.Sprintf("unnecessarily quoted appearance of `case:%s` tag option; specify `case:%s` instead",
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rawOpt, opt))
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}
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switch opt {
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case "ignore":
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case "strict":
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default:
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report.Report(pass, field.Tag,
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fmt.Sprintf("invalid appearance of unknown `case:%s` tag value", rawOpt))
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}
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case "inline":
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case "unknown":
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case "omitzero":
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case "omitempty":
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case "string":
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const msg = "invalid appearance of `string` tag option; it is only intended for fields of numeric types or pointers to those"
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tset := typeutil.NewTypeSet(pass.TypesInfo.TypeOf(field.Type))
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if len(tset.Terms) == 0 {
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// TODO(dh): improve message, call out the use of type parameters
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report.Report(pass, field.Tag, msg)
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continue
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}
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for _, term := range tset.Terms {
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T := typeutil.Dereference(term.Type().Underlying())
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for _, term2 := range typeutil.NewTypeSet(T).Terms {
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basic, ok := term2.Type().Underlying().(*types.Basic)
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// We accept bools and strings because v1 of encoding/json
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// supports those. We don't mention that in the message,
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// however, because their support is accidental, and v2
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// doesn't support it.
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if !ok || (basic.Info()&(types.IsBoolean|types.IsInteger|types.IsFloat|types.IsString)) == 0 {
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// TODO(dh): improve message, show how we arrived at the type
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report.Report(pass, field.Tag, msg)
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}
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}
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}
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case "format":
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if !strings.HasPrefix(tag, ":") {
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report.Report(pass, field.Tag, "missing value for `format` tag option")
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break
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}
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tag = tag[len(":"):]
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_, n, err := consumeTagOption(tag)
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if err != nil {
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report.Report(pass, field.Tag,
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fmt.Sprintf("malformed value for `format` tag option: %v", err))
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break
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}
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tag = tag[n:]
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wasFormat = true
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default:
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// Reject keys that resemble one of the supported options.
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// This catches invalid mutants such as "omitEmpty" or "omit_empty".
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normOpt := strings.ReplaceAll(strings.ToLower(opt), "_", "")
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switch normOpt {
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case "case", "inline", "unknown", "omitzero", "omitempty", "string", "format":
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report.Report(pass, field.Tag,
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fmt.Sprintf("invalid appearance of `%s` tag option; specify `%s` instead",
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opt, normOpt))
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default:
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report.Report(pass, field.Tag,
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fmt.Sprintf("invalid appearance of unknown `%s` tag option", opt))
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}
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}
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// Reject duplicates.
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if seenOpts[opt] {
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report.Report(pass, field.Tag,
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fmt.Sprintf("duplicate appearance of `%s` tag option", rawOpt))
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}
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seenOpts[opt] = true
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}
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if seenOpts["inline"] && seenOpts["unknown"] {
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report.Report(pass, field.Tag,
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"field cannot have both `inline` and `unknown` specified")
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}
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// TODO(dh): implement more restrictions for types of inlined and unknown
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// fields, including recursive restrictions:
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//
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// - Go struct field %s cannot have any options other than `inline` or `unknown` specified
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// - inlined Go struct field %s of type %s with `unknown` tag must be a Go map of string key or a jsontext.Value
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// - inlined Go struct field %s is not exported
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// - inlined map field %s of type %s must have a string key that does not implement marshal or unmarshal methods
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// - inlined Go struct field %s of type %s must be a Go struct, Go map of string key, or jsontext.Value
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}
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// consumeTagOption consumes the next option,
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// which is either a Go identifier or a single-quoted string.
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// If the next option is invalid, it returns all of in until the next comma,
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// and reports an error.
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func consumeTagOption(in string) (string, int, error) {
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// For legacy compatibility with v1, assume options are comma-separated.
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i := strings.IndexByte(in, ',')
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if i < 0 {
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i = len(in)
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}
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switch r, _ := utf8.DecodeRuneInString(in); {
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// Option as a Go identifier.
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case r == '_' || unicode.IsLetter(r):
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n := len(in) - len(strings.TrimLeftFunc(in, isLetterOrDigit))
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return in[:n], n, nil
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// Option as a single-quoted string.
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case r == '\'':
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// The grammar is nearly identical to a double-quoted Go string literal,
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// but uses single quotes as the terminators. The reason for a custom
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// grammar is because both backtick and double quotes cannot be used
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// verbatim in a struct tag.
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//
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// Convert a single-quoted string to a double-quote string and rely on
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// strconv.Unquote to handle the rest.
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var inEscape bool
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b := []byte{'"'}
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n := len(`'`)
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for len(in) > n {
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r, rn := utf8.DecodeRuneInString(in[n:])
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switch {
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case inEscape:
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if r == '\'' {
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b = b[:len(b)-1] // remove escape character: `\'` => `'`
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}
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inEscape = false
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case r == '\\':
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inEscape = true
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case r == '"':
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b = append(b, '\\') // insert escape character: `"` => `\"`
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case r == '\'':
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b = append(b, '"')
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n += len(`'`)
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out, err := strconv.Unquote(string(b))
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if err != nil {
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return in[:i], i, fmt.Errorf("invalid single-quoted string: %s", in[:n])
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}
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return out, n, nil
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}
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b = append(b, in[n:][:rn]...)
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n += rn
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}
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if n > 10 {
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n = 10 // limit the amount of context printed in the error
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}
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//lint:ignore ST1005 The ellipsis denotes truncated text
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return in[:i], i, fmt.Errorf("single-quoted string not terminated: %s...", in[:n])
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case len(in) == 0:
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return in[:i], i, io.ErrUnexpectedEOF
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default:
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return in[:i], i, fmt.Errorf("invalid character %q at start of option (expecting Unicode letter or single quote)", r)
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}
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}
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func isLetterOrDigit(r rune) bool {
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return r == '_' || unicode.IsLetter(r) || unicode.IsNumber(r)
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}
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