fix: find descendants of a non-existing tree parent (#8557)

* fix: find descendants of a non-existing tree parent

Closes: #8556

* Change default connection name(try another build)

Co-authored-by: Astrit Shehu <a.shehu@linkplus-ks.com>

src/repository/TreeRepository.ts

@@ -137,7 +137,7 @@ export class TreeRepository<Entity> extends Repository<Entity> {
                     if (this.manager.connection.driver instanceof AbstractSqliteDriver) {
                         return `${alias}.${this.metadata.materializedPathColumn!.propertyPath} LIKE ${subQuery.getQuery()} || '%'`;
                     } else {
-                        return `${alias}.${this.metadata.materializedPathColumn!.propertyPath} LIKE CONCAT(${subQuery.getQuery()}, '%')`;
+                        return `${alias}.${this.metadata.materializedPathColumn!.propertyPath} LIKE NULLIF(CONCAT(${subQuery.getQuery()}, '%'), '%')`;
                     }
                 });
         }

test/github-issues/8556/entity/category.entity.ts

@@ -0,0 +1,19 @@
+import {Column, PrimaryGeneratedColumn, Tree, TreeParent, TreeChildren} from "../../../../src";
+import {Entity} from "../../../../src/decorator/entity/Entity";
+
+@Entity()
+@Tree("materialized-path")
+export class Category {
+
+    @PrimaryGeneratedColumn()
+    id: number;
+
+    @Column()
+    name: string;
+
+    @TreeChildren()
+    children: Category[];
+
+    @TreeParent()
+    parent: Category;
+}

test/github-issues/8556/issue-8556.ts

@@ -0,0 +1,59 @@
+import "reflect-metadata";
+import {
+    createTestingConnections,
+    closeTestingConnections,
+    reloadTestingDatabases,
+    generateRandomText
+} from "../../utils/test-utils";
+import {Connection} from "../../../src/connection/Connection";
+import {expect} from "chai";
+import {Category} from "./entity/category.entity";
+import {TreeRepository} from "../../../src";
+
+describe("github issues > #8556 TreeRepository.findDescendants/Tree should return empty if tree parent entity does not exist", () => {
+    let connections: Connection[];
+    before(
+        async () =>
+        (connections = await createTestingConnections({
+            entities: [__dirname + "/entity/*{.js,.ts}"],
+            dropSchema: true,
+            schemaCreate: true,
+            name: generateRandomText(10)// Use a different name to avoid a random failure in build pipeline
+        }))
+    );
+
+    beforeEach(() => reloadTestingDatabases(connections));
+    after(() => closeTestingConnections(connections));
+
+    it("should load descendants when findDescendants is called for a tree entity", () =>
+        Promise.all(
+            connections.map(async connection => {
+                const repo: TreeRepository<Category> = connection.getTreeRepository(Category);
+                const root: Category = await repo.save({ id: 1, name: "root" } as Category);
+                await repo.save({ id: 2, name: "child", parent: root } as Category);
+                const descendantsIncludingParent = await repo.findDescendants(root);
+                expect(descendantsIncludingParent.length).to.be.equal(2);
+                const descendantTree = await repo.findDescendantsTree(root);
+                expect(descendantTree.children.length).to.be.equal(1);
+                const countDescendantsIncludingParent = await repo.countDescendants(root)
+                expect(countDescendantsIncludingParent).to.be.equal(2);
+            })
+        )
+    );
+
+    it("should return empty when findDescendants is called for a non existing tree entity", () =>
+        Promise.all(
+            connections.map(async connection => {
+                const repo: TreeRepository<Category> = connection.getTreeRepository(Category);
+                const root: Category = await repo.save({ id: 1, name: "root" } as Category);
+                await repo.save({ id: 2, name: "child", parent: root } as Category);
+                const descendantsOfNonExistingParent = await repo.findDescendants({id: -1} as Category);
+                expect(descendantsOfNonExistingParent.length).to.be.equal(0);
+                const descendantTree = await repo.findDescendantsTree({id: -1} as Category);
+                expect(descendantTree.children.length).to.be.equal(0);
+                const countDescendantsIncludingParent = await repo.countDescendants({id: -1} as Category)
+                expect(countDescendantsIncludingParent).to.be.equal(0);
+            })
+        )
+    );
+});