Foundry376/Mailspring · error · Error

Validation failed at ${keyPath}, ${JSON.stringify(value)} mu

Error message

Validation failed at ${keyPath}, ${JSON.stringify(value)} must be a boolean or the string 'true' or 'false'

What it means

Config schema enforcer for type 'boolean': the value is neither a real boolean nor one of the case-insensitive strings 'true'/'false' (e.g. 1, 'yes', undefined object types). The config system only accepts those narrow forms when coercing booleans.

Source

Thrown at app/src/config.ts:796

          `Validation failed at ${keyPath}, ${JSON.stringify(
            value
          )} cannot be coerced into a number`
        );
      }
      return value;
    },
  },

  boolean: {
    coerce(keyPath, value, schema) {
      switch (typeof value) {
        case 'string':
          if (value.toLowerCase() === 'true') {
            return true;
          } else if (value.toLowerCase() === 'false') {
            return false;
          } else {
            throw new Error(
              `Validation failed at ${keyPath}, ${JSON.stringify(
                value
              )} must be a boolean or the string 'true' or 'false'`
            );
          }
        case 'boolean':
          return value;
        default:
          throw new Error(
            `Validation failed at ${keyPath}, ${JSON.stringify(
              value
            )} must be a boolean or the string 'true' or 'false'`
          );
      }
    },
  },

  string: {

View on GitHub (pinned to 648c685d60)

Solutions

1. Set the key to true, false, or the exact strings 'true'/'false'
2. Convert boolean-like inputs (checkbox tri-state, 0/1) before calling config.set

When it happens

Trigger: Thrown at app/src/config.ts:796 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of Foundry376/Mailspring@648c685d60 (2026-09-03). Data as JSON: /api/errors/25c76457e824769c. Report an issue: GitHub.