From 0094ded5c495dd4a619112f0ea38e37037309d8d Mon Sep 17 00:00:00 2001
From: Raymond Feng <enjoyjava@gmail.com>
Date: Thu, 12 Sep 2019 09:35:45 -0700
Subject: [PATCH] fix(repository): allow model classes with recursive type
 references
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Fixes https://github.com/strongloop/loopback-next/issues/3671#issuecomment-529376105


Co-authored-by: Miroslav Bajtoš <mbajtoss@gmail.com>
---
 .../legacy-juggler-bridge.unit.ts             | 29 +++++++++++++++++++
 .../src/repositories/legacy-juggler-bridge.ts |  4 +++
 2 files changed, 33 insertions(+)

diff --git a/packages/repository/src/__tests__/unit/repositories/legacy-juggler-bridge.unit.ts b/packages/repository/src/__tests__/unit/repositories/legacy-juggler-bridge.unit.ts
index ee7d4ac1dee7..63de1a675e16 100644
--- a/packages/repository/src/__tests__/unit/repositories/legacy-juggler-bridge.unit.ts
+++ b/packages/repository/src/__tests__/unit/repositories/legacy-juggler-bridge.unit.ts
@@ -210,6 +210,35 @@ describe('DefaultCrudRepository', () => {
       expect(User.definition.properties.roles.itemType).to.equal(Role);
       expect(User.definition.properties.address.type).to.equal(Address);
     });
+
+    it('handles recursive model references', () => {
+      @model()
+      class ReportState extends Entity {
+        @property({id: true})
+        id: string;
+
+        @property.array(ReportState, {})
+        states: ReportState[];
+
+        @property({
+          type: 'string',
+        })
+        benchmarkId?: string;
+
+        @property({
+          type: 'string',
+        })
+        color?: string;
+
+        constructor(data?: Partial<ReportState>) {
+          super(data);
+        }
+      }
+      const repo = new DefaultCrudRepository(ReportState, ds);
+      const definition = repo.modelClass.definition;
+      const typeOfStates = definition.properties.states.type;
+      expect(typeOfStates).to.eql([repo.modelClass]);
+    });
   });
 
   it('shares the backing PersistedModel across repo instances', () => {
diff --git a/packages/repository/src/repositories/legacy-juggler-bridge.ts b/packages/repository/src/repositories/legacy-juggler-bridge.ts
index 5606125d0129..c2f6de4b666a 100644
--- a/packages/repository/src/repositories/legacy-juggler-bridge.ts
+++ b/packages/repository/src/repositories/legacy-juggler-bridge.ts
@@ -148,6 +148,10 @@ export class DefaultCrudRepository<
       return model as typeof juggler.PersistedModel;
     }
 
+    // To handle circular reference back to the same model,
+    // we create a placeholder model that will be replaced by real one later
+    dataSource.getModel(definition.name, true /* forceCreate */);
+
     // We need to convert property definitions from PropertyDefinition
     // to plain data object because of a juggler limitation
     const properties: {[name: string]: object} = {};