/**
 * @license
 * Copyright 2025 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */
/**
 * Interface that all settings migrations must implement.
 * Each migration handles a single version transition (N → N+1).
 */
export interface SettingsMigration {
    /** Source version number */
    readonly fromVersion: number;
    /** Target version number */
    readonly toVersion: number;
    /**
     * Determines whether this migration should be applied to the given settings.
     * The migration inspects the settings object to detect its current version
     * and returns true if this migration is applicable.
     *
     * @param settings - The current settings object
     * @returns true if this migration should be applied, false otherwise
     */
    shouldMigrate(settings: unknown): boolean;
    /**
     * Executes the migration transformation.
     * This should be a pure function that does not modify the input object.
     *
     * @param settings - The current settings object of version N
     * @param scope - The scope of settings being migrated
     * @returns The migrated settings object of version N+1 with optional warnings
     * @throws Error if the migration fails
     */
    migrate(settings: unknown, scope: string): {
        settings: unknown;
        warnings: string[];
    };
}
/**
 * Result of a migration execution by MigrationScheduler.
 */
export interface MigrationResult {
    /** The final settings object after all applicable migrations */
    settings: unknown;
    /** The final version number after migrations */
    finalVersion: number;
    /** List of migrations that were executed */
    executedMigrations: Array<{
        fromVersion: number;
        toVersion: number;
    }>;
    /** List of warning messages generated during migration */
    warnings: string[];
}