wavetermdev/waveterm · error

cannot convert %s: %v

Error message

cannot convert %s: %v

What it means

SetBaseConfigValue wraps a convertJsonNumber failure as 'cannot convert %s: %v' when the supplied value is a json.Number that cannot be converted to the key's declared type (int64, float64, or string). The key name and the inner conversion error are included.

Source

Thrown at pkg/wconfig/settingsconfig.go:865

	if len(cerrs) > 0 {
		return fmt.Errorf("error reading config file: %v", cerrs[0])
	}
	if m == nil {
		m = make(waveobj.MetaMapType)
	}
	for configKey, val := range toMerge {
		ctype := getConfigKeyType(configKey)
		if ctype == nil {
			return fmt.Errorf("invalid config key: %s", configKey)
		}
		if val == nil {
			delete(m, configKey)
		} else {
			rtype := reflect.TypeOf(val)
			if rtype == reflect.TypeOf(dummyNumber) {
				convertedVal, err := convertJsonNumber(val.(json.Number), ctype)
				if err != nil {
					return fmt.Errorf("cannot convert %s: %v", configKey, err)
				}
				val = convertedVal
				rtype = reflect.TypeOf(val)
			}
			if rtype != ctype {
				if ctype == reflect.PointerTo(rtype) {
					m[configKey] = &val
				} else {
					return fmt.Errorf("invalid value type for %s: %T", configKey, val)
				}
			}
			m[configKey] = val
		}
	}
	return WriteWaveHomeConfigFile(SettingsFile, m)
}

func SetConnectionsConfigValue(connName string, toMerge waveobj.MetaMapType) error {

View on GitHub (pinned to a4447c1563)

Solutions

1. Read the inner error: fix the number (make it integral, in range, or valid)
2. Prefer passing native Go types (int64, float64, string, bool) instead of json.Number
3. Confirm the key's declared type matches the value you are supplying

Example fix

// before
wconfig.SetBaseConfigValue(waveobj.MetaMapType{"term:fontsize": json.Number("12.75")})
// after
wconfig.SetBaseConfigValue(waveobj.MetaMapType{"term:fontsize": 13})

// decode numbers into concrete types before merging
if raw, ok := val.(json.Number); ok {
    if i, err := raw.Int64(); err == nil {
        val = i
    } else if f, err := raw.Float64(); err == nil {
        val = f
    }
}

if err := wconfig.SetBaseConfigValue(m); err != nil {
    if strings.Contains(err.Error(), "cannot convert") {
        return fmt.Errorf("fix numeric value type before merge: %w", err)
    }
    return err
}

When it happens

Trigger: Passing json.Number values via SetBaseConfigValue where the number is fractional/out-of-range for an int64 key, invalid for a float64 key, or the key's type is not number-convertible at all.

Common situations: Round-tripping parsed JSON where numbers arrive as json.Number; supplying decimals to integer settings; supplying numbers to boolean/struct settings.

Related errors

• invalid number for int64: %s
• invalid number for float64: %s
• cannot convert number to %s
• error setting telemetry value: %w
• error reading config file: %v

AI-assisted analysis of wavetermdev/waveterm@a4447c1563 (2026-09-01). Data as JSON: /api/errors/2589e098dd377a3a. Report an issue: GitHub.