fix: don't transform json(b) column value when computing update changes

src/persistence/SubjectChangedColumnsComputer.ts

@@ -61,9 +61,11 @@ export class SubjectChangedColumnsComputer {
 
             // if there is no database entity then all columns are treated as new, e.g. changed
             if (subject.databaseEntity) {
+                // skip transform database value for json / jsonb for comparison later on
+                const shouldTransformDatabaseEntity = column.type !== "json" && column.type !== "jsonb";
 
                 // get database value of the column
-                let databaseValue = column.getEntityValue(subject.databaseEntity, true);
+                let databaseValue = column.getEntityValue(subject.databaseEntity, shouldTransformDatabaseEntity);
 
                 // filter out "relational columns" only in the case if there is a relation object in entity
                 if (column.relationMetadata) {

test/other-issues/transformed-json-column-update-compute/entity/json-entity.ts

@@ -0,0 +1,17 @@
+import { Entity } from "../../../../src/decorator/entity/Entity";
+import { Column } from "../../../../src/decorator/columns/Column";
+import { PrimaryGeneratedColumn } from "../../../../src/decorator/columns/PrimaryGeneratedColumn";
+import { VersionColumn } from "../../../../src";
+import { testTransformer } from "../test-transformer";
+
+@Entity()
+export class DummyJSONEntity {
+	@PrimaryGeneratedColumn()
+	id: number;
+
+	@VersionColumn()
+	version: number;
+
+	@Column({ type: "json", transformer: testTransformer })
+	value: Record<string, any>;
+}

test/other-issues/transformed-json-column-update-compute/entity/jsonb-entity.ts

@@ -0,0 +1,17 @@
+import { Entity } from "../../../../src/decorator/entity/Entity";
+import { Column } from "../../../../src/decorator/columns/Column";
+import { PrimaryGeneratedColumn } from "../../../../src/decorator/columns/PrimaryGeneratedColumn";
+import { VersionColumn } from "../../../../src";
+import { testTransformer } from "../test-transformer";
+
+@Entity()
+export class DummyJSONBEntity {
+	@PrimaryGeneratedColumn()
+	id: number;
+
+	@VersionColumn()
+	version: number;
+
+	@Column({ type: "jsonb", transformer: testTransformer })
+	value: Record<string, any>;
+}

test/other-issues/transformed-json-column-update-compute/test-transformer.ts

@@ -0,0 +1,14 @@
+export const testTransformer = {
+	to(data: any) {
+		if ("secretProperty" in data) {
+			data.secretProperty = `secret-${data.secretProperty}`;
+		}
+		return data;
+	},
+	from(data: any) {
+		if ("secretProperty" in data) {
+			data.secretProperty = data.secretProperty.split("-")[1];
+		}
+		return data;
+	}
+};

test/other-issues/transformed-json-column-update-compute/transformed-json-column-update-compute.ts

@@ -0,0 +1,53 @@
+import "reflect-metadata";
+import { createTestingConnections, closeTestingConnections, reloadTestingDatabases } from "../../utils/test-utils";
+import { Connection } from "../../../src/connection/Connection";
+import { expect } from "chai";
+import { DummyJSONEntity } from "./entity/json-entity";
+import { DummyJSONBEntity } from "./entity/jsonb-entity";
+
+describe("other issues > correctly compute change for transformed json / jsonb columns", () => {
+
+	let connections: Connection[];
+	before(async () => connections = await createTestingConnections({
+		entities: [__dirname + "/entity/*{.js,.ts}"],
+		schemaCreate: true,
+		dropSchema: true,
+		enabledDrivers: ["postgres"]
+	}));
+	beforeEach(() => reloadTestingDatabases(connections));
+	after(() => closeTestingConnections(connections));
+
+	it("should not update entity if transformed JSON column did not change", () => Promise.all(connections.map(async connection => {
+		const repository = connection.getRepository(DummyJSONEntity);
+
+		const dummy = repository.create({
+			value: {
+				secretProperty: "hello"
+			},
+		});
+
+		await repository.save(dummy);
+
+		await repository.save(dummy);
+
+		const dummyEntity = await repository.findOneOrFail(dummy.id);
+		expect(dummyEntity.version).to.equal(1);
+	})));
+
+	it("should not update entity if transformed JSONB column did not change", () => Promise.all(connections.map(async connection => {
+		const repository = connection.getRepository(DummyJSONBEntity);
+
+		const dummy = repository.create({
+			value: {
+				secretProperty: "hello"
+			},
+		});
+
+		await repository.save(dummy);
+
+		await repository.save(dummy);
+
+		const dummyEntity = await repository.findOneOrFail(dummy.id);
+		expect(dummyEntity.version).to.equal(1);
+	})));
+});