fix: change InsertQueryBuilder.values() with an empty array into a no-op

src/entity-manager/EntityManager.ts

@@ -581,17 +581,6 @@ export class EntityManager {
      * You can execute bulk inserts using this method.
      */
     async insert<Entity>(target: ObjectType<Entity>|EntitySchema<Entity>|string, entity: QueryDeepPartialEntity<Entity>|(QueryDeepPartialEntity<Entity>[])): Promise<InsertResult> {
-
-        // If user passed empty array of entities then we don't need to do
-        // anything.
-        //
-        // Fixes GitHub issue #5734.  If we were to let this through we would
-        // run into problems downstream, like subscribers getting invoked with
-        // the empty array where they expect an entity, and SQL queries with an
-        // empty VALUES clause.
-        if (Array.isArray(entity) && entity.length === 0)
-            return Promise.resolve(new InsertResult());
-
         // TODO: Oracle does not support multiple values. Need to create another nice solution.
         if (this.connection.driver instanceof OracleDriver && Array.isArray(entity)) {
             const results = await Promise.all(entity.map(entity => this.insert(target, entity)));

src/query-builder/InsertQueryBuilder.ts

@@ -41,6 +41,20 @@ export class InsertQueryBuilder<Entity> extends QueryBuilder<Entity> {
      * Executes sql generated by query builder and returns raw database results.
      */
     async execute(): Promise<InsertResult> {
+        // console.time(".value sets");
+        const valueSets: ObjectLiteral[] = this.getValueSets();
+        // console.timeEnd(".value sets");
+
+        // If user passed empty array of entities then we don't need to do
+        // anything.
+        //
+        // Fixes GitHub issues #3111 and #5734. If we were to let this through
+        // we would run into problems downstream, like subscribers getting
+        // invoked with the empty array where they expect an entity, and SQL
+        // queries with an empty VALUES clause.
+        if (valueSets.length === 0)
+            return new InsertResult();
+
         // console.time("QueryBuilder.execute");
         // console.time(".database stuff");
         const queryRunner = this.obtainQueryRunner();
@@ -55,9 +69,6 @@ export class InsertQueryBuilder<Entity> extends QueryBuilder<Entity> {
             }
 
             // console.timeEnd(".database stuff");
-            // console.time(".value sets");
-            const valueSets: ObjectLiteral[] = this.getValueSets();
-            // console.timeEnd(".value sets");
 
             // call before insertion methods in listeners and subscribers
             if (this.expressionMap.callListeners === true && this.expressionMap.mainAlias!.hasMetadata) {
@@ -579,7 +590,7 @@ export class InsertQueryBuilder<Entity> extends QueryBuilder<Entity> {
      * Gets array of values need to be inserted into the target table.
      */
     protected getValueSets(): ObjectLiteral[] {
-        if (Array.isArray(this.expressionMap.valuesSet) && this.expressionMap.valuesSet.length > 0)
+        if (Array.isArray(this.expressionMap.valuesSet))
             return this.expressionMap.valuesSet;
 
         if (this.expressionMap.valuesSet instanceof Object)

test/github-issues/3111/entity/Test.ts

@@ -0,0 +1,14 @@
+import {Column} from "../../../../src/decorator/columns/Column";
+import {Entity} from "../../../../src/decorator/entity/Entity";
+import {PrimaryGeneratedColumn} from "../../../../src/decorator/columns/PrimaryGeneratedColumn";
+
+export const DEFAULT_VALUE = "default-value";
+
+@Entity()
+export class Test {
+    @PrimaryGeneratedColumn()
+    id: number;
+
+    @Column({default: DEFAULT_VALUE})
+    value: string;
+}

test/github-issues/3111/issue-3111.ts

@@ -0,0 +1,30 @@
+import "reflect-metadata";
+import {createTestingConnections, closeTestingConnections, reloadTestingDatabases} from "../../utils/test-utils";
+import {Connection} from "../../../src/connection/Connection";
+import {expect} from "chai";
+import {InsertValuesMissingError} from "../../../src/error/InsertValuesMissingError";
+import {Test, DEFAULT_VALUE} from "./entity/Test";
+
+describe("github issues > #3111 Inserting with query builder attempts to insert a default row when values is empty array", () => {
+
+    let connections: Connection[];
+    before(async () => connections = await createTestingConnections({
+        entities: [__dirname + "/entity/*{.js,.ts}"],
+        schemaCreate: true,
+        dropSchema: true,
+    }));
+    beforeEach(() => reloadTestingDatabases(connections));
+    after(() => closeTestingConnections(connections));
+
+    it("should not insert with default values on .values([])", () => Promise.all(connections.map(async connection => {
+        const repo = connection.getRepository(Test);
+        await repo.createQueryBuilder().insert().values([]).execute();
+        const rowsWithDefaultValue = await repo.find({ where: {value: DEFAULT_VALUE}});
+        expect(rowsWithDefaultValue).to.have.lengthOf(0);
+    })));
+
+    it("should still error on missing .values()", () => Promise.all(connections.map(async connection => {
+        const repo = connection.getRepository(Test);
+        await repo.createQueryBuilder().insert().execute().should.be.rejectedWith(InsertValuesMissingError);
+    })));
+});