| 1 | package culpa |
| 2 | |
| 3 | import ( |
| 4 | "fmt" |
| 5 | "log/slog" |
| 6 | "reflect" |
| 7 | "strings" |
| 8 | ) |
| 9 | |
| 10 | // Format implements [fmt.Formatter] for culpaError. |
| 11 | // |
| 12 | // - %v / %s — message chain only (same as Error()) |
| 13 | // - %+v — full dump: message chain, details, stacktraces |
| 14 | func (e *culpaError) Format(s fmt.State, verb rune) { formatError(s, verb, e) } |
| 15 | |
| 16 | // Format implements [fmt.Formatter] for detailsWrap. |
| 17 | func (d *detailsWrap) Format(s fmt.State, verb rune) { formatError(s, verb, d) } |
| 18 | |
| 19 | // Format implements [fmt.Formatter] for joinedError. |
| 20 | func (e *joinedError) Format(s fmt.State, verb rune) { formatError(s, verb, e) } |
| 21 | |
| 22 | func formatError(s fmt.State, verb rune, err error) { |
| 23 | switch verb { |
| 24 | case 'v': |
| 25 | if s.Flag('+') { |
| 26 | fmt.Fprint(s, err.Error()) |
| 27 | printDetails(s, err) |
| 28 | return |
| 29 | } |
| 30 | fallthrough |
| 31 | case 's': |
| 32 | fmt.Fprint(s, err.Error()) |
| 33 | case 'q': |
| 34 | fmt.Fprintf(s, "%q", err.Error()) |
| 35 | } |
| 36 | } |
| 37 | |
| 38 | func printDetails(w fmt.State, err error) { |
| 39 | walkTree(err, func(e error) bool { |
| 40 | if dw, ok := e.(*detailsWrap); ok { |
| 41 | for _, d := range dw.details { |
| 42 | if st, ok := d.(StacktraceDetail); ok { |
| 43 | fmt.Fprintf(w, "\n--- stacktrace ---\n%+v", st.Trace) |
| 44 | continue |
| 45 | } |
| 46 | fmt.Fprintf(w, "\n %s: %+v", detailTypeName(d), d) |
| 47 | } |
| 48 | } |
| 49 | return true |
| 50 | }) |
| 51 | } |
| 52 | |
| 53 | // LogValue implements [slog.LogValuer] so that culpa errors produce |
| 54 | // structured output when passed to slog. |
| 55 | func (e *culpaError) LogValue() slog.Value { return logValue(e) } |
| 56 | |
| 57 | // LogValue implements [slog.LogValuer] for detailsWrap. |
| 58 | func (d *detailsWrap) LogValue() slog.Value { return logValue(d) } |
| 59 | |
| 60 | // LogValue implements [slog.LogValuer] for joinedError. |
| 61 | func (e *joinedError) LogValue() slog.Value { return logValue(e) } |
| 62 | |
| 63 | func logValue(err error) slog.Value { |
| 64 | attrs := []slog.Attr{slog.String("msg", err.Error())} |
| 65 | |
| 66 | seen := make(map[reflect.Type]bool) |
| 67 | walkTree(err, func(e error) bool { |
| 68 | if dw, ok := e.(*detailsWrap); ok { |
| 69 | for _, d := range dw.details { |
| 70 | dt := reflect.TypeOf(d) |
| 71 | if dt == reflect.TypeOf(StacktraceDetail{}) { |
| 72 | continue |
| 73 | } |
| 74 | if seen[dt] { |
| 75 | continue |
| 76 | } |
| 77 | seen[dt] = true |
| 78 | key := detailKey(dt) |
| 79 | attrs = append(attrs, slog.Any(key, d)) |
| 80 | } |
| 81 | } |
| 82 | return true |
| 83 | }) |
| 84 | |
| 85 | // Output stacktrace.Trace directly so handlers can format as needed |
| 86 | traces := FindDetails[StacktraceDetail](err) |
| 87 | if len(traces) > 0 { |
| 88 | if len(traces) == 1 { |
| 89 | attrs = append(attrs, slog.Any("stacktrace", traces[0].Trace)) |
| 90 | } else { |
| 91 | // Multiple traces - collect them |
| 92 | traceVals := make([]any, len(traces)) |
| 93 | for i, st := range traces { |
| 94 | traceVals[i] = st.Trace |
| 95 | } |
| 96 | attrs = append(attrs, slog.Any("stacktrace", traceVals)) |
| 97 | } |
| 98 | } |
| 99 | |
| 100 | return slog.GroupValue(attrs...) |
| 101 | } |
| 102 | |
| 103 | func detailTypeName(d any) string { |
| 104 | t := reflect.TypeOf(d) |
| 105 | if t.Kind() == reflect.Pointer { |
| 106 | t = t.Elem() |
| 107 | } |
| 108 | return t.Name() |
| 109 | } |
| 110 | |
| 111 | func detailKey(t reflect.Type) string { |
| 112 | if t.Kind() == reflect.Pointer { |
| 113 | t = t.Elem() |
| 114 | } |
| 115 | name := t.Name() |
| 116 | name = strings.TrimSuffix(name, "Detail") |
| 117 | if name == "" { |
| 118 | return t.Name() |
| 119 | } |
| 120 | return strings.ToLower(name[:1]) + name[1:] |
| 121 | } |
| 122 | |