Module migrate_backend_cmd 

Cross-backend database migration command implementation

Handles migration between SQLite backends (copy with side table migration).

Architecture

This module uses sqlitegraph’s GraphBackend::snapshot_export() and snapshot_import() methods for graph data migration. The wrapper only handles directory creation and returns Magellan-specific metadata.

Side Tables

GraphBackend does NOT handle Magellan-specific side tables:

• code_chunks - Code snippets stored in generation module
• file_metrics, symbol_metrics - Pre-computed metrics
• execution_log - Command execution tracking
• ast_nodes - AST hierarchy storage
• cfg_blocks - Control flow graph data

These must be migrated separately via direct SQL.

Structs

BackendMigrationResult

Result of a backend migration operation

SnapshotExportMetadata

Snapshot export metadata returned by export_snapshot

SnapshotImportMetadata

Snapshot import metadata returned by import_snapshot

Enums

BackendFormat

Database backend format

MigrationError

Errors that can occur during backend format detection

Functions

detect_backend_format

Detect the backend format of a database file

export_snapshot

Export graph data from a backend to a snapshot directory

get_graph_counts

Get entity and edge counts from a graph backend

import_snapshot

Import graph data from a snapshot directory into a backend

migrate_side_tables

Migrate Magellan-specific side tables from source to target database

run_migrate_backend

Run a complete backend migration from source to target database

verify_import_counts

Verify that imported counts match exported counts