Method processO2M

api/src/services/payload.ts:765–1076

* Recursively save/update all nested related o2m items

(
		data: Partial<Item>,
		parent: PrimaryKey,
		opts?: MutationOptions,
	)

	 * Recursively save/update all nested related o2m items
	 */
	async processO2M(
		data: Partial<Item>,
		parent: PrimaryKey,
		opts?: MutationOptions,
	): Promise<PayloadServiceProcessRelationResult> {
		const revisions: PrimaryKey[] = [];
		let userIntegrityCheckFlags = UserIntegrityCheckFlag.None;

		const nestedActionEvents: ActionEventParams[] = [];

		const relations = this.schema.relations.filter((relation) => {
			return relation.related_collection === this.collection;
		});

		const payload = cloneDeep(data);

		// Only process related records that are actually in the payload
		const relationsToProcess = relations.filter((relation) => {
			if (!relation.meta?.one_field) return false;
			return relation.meta.one_field in payload;
		});

		const nestedUpdateSchema = Joi.object({
			create: Joi.array().items(Joi.object().unknown()),
			update: Joi.array().items(Joi.object().unknown()),
			delete: Joi.array().items(Joi.string(), Joi.number()),
		});

		for (const relation of relationsToProcess) {
			if (!relation.meta) continue;

			const currentPrimaryKeyField = this.schema.collections[relation.related_collection!]!.primary;
			const relatedPrimaryKeyField = this.schema.collections[relation.collection]!.primary;

			const { getService } = await import('../utils/get-service.js');

			const service = getService(relation.collection, {
				accountability: this.accountability,
				knex: this.knex,
				schema: this.schema,
				nested: [...this.nested, relation.meta!.one_field!],
			});

			const recordsToUpsert: Partial<Item>[] = [];
			const savedPrimaryKeys: PrimaryKey[] = [];

			// Nested array of individual items
			const field = payload[relation.meta!.one_field!];

			if (!field || Array.isArray(field)) {
				const updates = field || []; // treat falsey values as removing all children

				for (let i = 0; i < updates.length; i++) {
					const currentId = parent || payload[currentPrimaryKeyField];
					const relatedRecord = updates[i];

					const relatedId =
						typeof relatedRecord === 'string' || typeof relatedRecord === 'number'