YunaiV/yudao-cloud · error · UnexpectedLiquibaseException

Cannot convert type {} to a boolean value

Error message

Cannot convert type {} to a boolean value

What it means

BooleanType.objectToSqlValue only converts String, Long, Number, DatabaseFunction and Boolean instances. Any other Java type (Date, char[], custom object, null-with-unexpected-type) falls to the final else and throws, reporting the offending class name in the message.

Source

Thrown at sql/dm/flowable-patch/src/main/java/liquibase/datatype/core/BooleanType.java:108

            } else {
                returnValue = this.getFalseBooleanValue(database);
            }
        } else if (value instanceof Number) {
            if (value.equals(1) || "1".equals(value.toString()) || "1.0".equals(value.toString())) {
                returnValue = this.getTrueBooleanValue(database);
            } else {
                returnValue = this.getFalseBooleanValue(database);
            }
        } else if (value instanceof DatabaseFunction) {
            return value.toString();
        } else if (value instanceof Boolean) {
            if (((Boolean) value)) {
                returnValue = this.getTrueBooleanValue(database);
            } else {
                returnValue = this.getFalseBooleanValue(database);
            }
        } else {
            throw new UnexpectedLiquibaseException("Cannot convert type " + value.getClass() + " to a boolean value");
        }

        return returnValue;
    }

    protected boolean isNumericBoolean(Database database) {
        if (database instanceof Firebird3Database) {
            return false;
        }
        if (database instanceof DerbyDatabase) {
            return !((DerbyDatabase) database).supportsBooleanDataType();
        } else if (database instanceof DB2Database) {
            return !((DB2Database) database).supportsBooleanDataType();
        }
        return (database instanceof Db2zDatabase)
            || (database instanceof FirebirdDatabase)
            || (database instanceof MSSQLDatabase)
            || (database instanceof MySQLDatabase)

View on GitHub (pinned to 477be9dd49)

Solutions

1. Convert the value to String/Boolean/Number before setting it: String.valueOf(value) for '1'/'0'/'true'/'false'.
2. Use Boolean.TRUE/FALSE or Integer 1/0 for numeric-boolean databases.
3. Wrap computed SQL in new DatabaseFunction("...") instead of raw objects.
4. Inspect the class name printed in the message to find the exact caller passing the bad type.

Example fix

// before
column.setDefaultValue(Character.valueOf('1'));

// after
column.setDefaultValue("1");

Object v = column.getDefaultValue();
if (!(v == null || v instanceof String || v instanceof Boolean || v instanceof Number || v instanceof DatabaseFunction)) {
    v = String.valueOf(v); // coerce before Liquibase sees it
    column.setDefaultValue(v);
}

static boolean convertibleToLiquibaseBoolean(Object v) {
    return v == null || v instanceof String || v instanceof Boolean
        || v instanceof Number || v instanceof DatabaseFunction;
}

try { sqlValue = boolType.objectToSqlValue(v, db); }
catch (UnexpectedLiquibaseException e) {
    if (e.getMessage().startsWith("Cannot convert type")) {
        sqlValue = v == null ? null : String.valueOf(v); // explicit fallback
    } else throw e;
}

When it happens

Trigger: Programmatic API use where a Changeset/column value is set with an unsupported object, e.g. Column.setDefaultValue(Character 'Y'), a java.util.Date, or a char primitive boxed as Character. Character values are the classic case: '1' as char is not the String "1".

Common situations: Code that builds Liquibase Change objects dynamically and passes raw types from an ORM or CSV import; upgrading Liquibase versions where previously-silently-coerced types now fail; using setDefaultValue(new Character('0')).

Related errors

• Unknown boolean value: {}
• Cannot determine the Oracle database version number
• 未知的数据类型：{}

AI-assisted analysis of YunaiV/yudao-cloud@477be9dd49 (2026-08-14). Data as JSON: /api/errors/25a50151f5d65d79. Report an issue: GitHub.