Function applyDiff

api/src/utils/apply-diff.ts:37–372

(
	currentSnapshot: Snapshot,
	snapshotDiff: SnapshotDiff,
	options?: { database?: Knex; schema?: SchemaOverview },
)

const logger = useLogger();

export async function applyDiff(
	currentSnapshot: Snapshot,
	snapshotDiff: SnapshotDiff,
	options?: { database?: Knex; schema?: SchemaOverview },
): Promise<void> {
	const database = options?.database ?? getDatabase();
	const helpers = getHelpers(database);
	const schema = options?.schema ?? (await getSchema({ database, bypassCache: true }));

	const nestedActionEvents: ActionEventParams[] = [];

	const mutationOptions: MutationOptions = {
		autoPurgeSystemCache: false,
		bypassEmitAction: (params) => nestedActionEvents.push(params),
		bypassLimits: true,
	};

	const runPostColumnChange = await helpers.schema.preColumnChange();

	await transaction(database, async (trx) => {
		const collectionsService = new CollectionsService({ knex: trx, schema });

		const getNestedCollectionsToCreate = (currentLevelCollection: string) =>
			snapshotDiff.collections.filter(
				({ diff }) => (diff[0] as DiffNew<Collection>).rhs?.meta?.group === currentLevelCollection,
			) as CollectionDelta[];

		const createCollections = async (collections: CollectionDelta[]) => {
			for (const { collection, diff } of collections) {
				if (diff?.[0]?.kind === DiffKind.NEW && diff[0].rhs) {
					// We'll nest the to-be-created fields in the same collection creation, to prevent
					// creating a collection without a primary key
					const fields = snapshotDiff.fields
						.filter((fieldDiff) => fieldDiff.collection === collection)
						.map((fieldDiff) => (fieldDiff.diff[0] as DiffNew<Field>).rhs)
						.map((fieldDiff) => {
							// Casts field type to UUID when applying non-PostgreSQL schema onto PostgreSQL database.
							// This is needed because they snapshots UUID fields as char/varchar with length 36.
							if (
								['char', 'varchar'].includes(String(fieldDiff.schema?.data_type).toLowerCase()) &&
								fieldDiff.schema?.max_length === 36 &&
								(fieldDiff.schema?.is_primary_key ||
									(fieldDiff.schema?.foreign_key_table && fieldDiff.schema?.foreign_key_column))
							) {
								return merge(fieldDiff, { type: 'uuid', schema: { data_type: 'uuid', max_length: null } });
							} else {
								return fieldDiff;
							}
						});

					try {
						await collectionsService.createOne(
							{
								...diff[0].rhs,
								fields,
							},
							mutationOptions,
						);