[crazy-max]

Fix trace decoding failures and data loss affecting build history and desktop bundle exports. The existing decoder stores attribute values in any, but encoding/json decodes arrays as []any and numbers as float64. The attribute conversion code at

buildx/util/otelutil/span.go

Lines 275 to 340 in c43f837

	func (kv *keyValue) asAttributeKeyValue() (attribute.KeyValue, error) {
	// value types get encoded as string
	switch kv.Value.Type {
	case attribute.EMPTY.String():
	return attribute.KeyValue{}, errors.New("invalid value type")
	case attribute.BOOL.String():
	return attribute.Bool(kv.Key, kv.Value.Value.(bool)), nil
	case attribute.INT64.String():
	// value could be int64 or float64, so handle both cases (float64 comes
	// from json unmarshal)
	var v int64
	switch i := kv.Value.Value.(type) {
	case int64:
	v = i
	case float64:
	v = int64(i)
	}
	return attribute.Int64(kv.Key, v), nil
	case attribute.FLOAT64.String():
	return attribute.Float64(kv.Key, kv.Value.Value.(float64)), nil
	case attribute.STRING.String():
	return attribute.String(kv.Key, kv.Value.Value.(string)), nil
	case attribute.BOOLSLICE.String():
	return attribute.BoolSlice(kv.Key, kv.Value.Value.([]bool)), nil
	case attribute.INT64SLICE.String():
	// handle both float64 and int64 (float64 comes from json unmarshal)
	var v []int64
	switch sli := kv.Value.Value.(type) {
	case []int64:
	v = sli
	case []float64:
	for i := range sli {
	v = append(v, int64(sli[i]))
	}
	}
	return attribute.Int64Slice(kv.Key, v), nil
	case attribute.FLOAT64SLICE.String():
	return attribute.Float64Slice(kv.Key, kv.Value.Value.([]float64)), nil
	case attribute.STRINGSLICE.String():
	var strSli []string
	// sometimes we can get an []interface{} instead of a []string, so
	// always cast to []string if that happens.
	switch sli := kv.Value.Value.(type) {
	case []string:
	strSli = sli
	case []any:
	for i := range sli {
	var v string
	// best case we have a string, otherwise, cast it using
	// fmt.Sprintf
	if str, ok := sli[i].(string); ok {
	v = str
	} else {
	v = fmt.Sprintf("%v", sli[i])
	}
	// add the string to the slice
	strSli = append(strSli, v)
	}
	default:
	return attribute.KeyValue{}, errors.Errorf("got unsupported type %q for %s", reflect.ValueOf(kv.Value.Value).Kind(), attribute.STRINGSLICE.String())
	}
	return attribute.StringSlice(kv.Key, strSli), nil
	default:
	return attribute.KeyValue{}, errors.Errorf("unknown value type %s", kv.Value.Type)
	}
	}

instead asserts typed slices or handles only typed numeric slices. Reproductions confirmed that boolean and float slices panic, integer slices become empty, and the integer 9007199254740993 becomes 9007199254740992. Decode values according to their declared OTel types so slices survive and integers retain their precision, with errors for malformed values instead of panics or implicit coercion.

Support the full attribute model exposed by the pinned OTel 1.46.0 dependency, including EMPTY, BYTESLICE, SLICE, and MAP. Previously, these valid types caused the entire trace to fail decoding. Preserve nested values and instrumentation-scope attributes, prefer InstrumentationScope when present, and retain compatibility with InstrumentationLibrary. Jaeger conversion now represents bytes as binary tags and complex values as JSON strings instead of silently dropping them.

Preserve trace flags and tracestate during decoding and bundle export. The previous decoder recognized only the exact flags string "01", so "03" lost both the sampled and random-ID bits. OTel defines the random-ID flag as 0x02, while Jaeger uses that bit for debug. Preserve the OTel flags internally and transfer only the shared sampled bit to Jaeger.

Keep older bundles readable while fixing scope-attribute preservation in new exports. The bundle sanitizer encoded spans by value, bypassing attribute.Set pointer-receiver JSON marshaler and writing scope attributes as {}. Encode spans by pointer to preserve their attributes, and continue accepting the legacy object representation.

I used Codex to investigate the issues, then cross-checked the changes with Claude Code. That review caught a compatibility issue with scope attributes in older bundles, which was reproduced and fixed before a follow-up review.