fix: update BindingToSyntax.toService() to resolve async dependencies

CHANGELOG.md

@@ -11,6 +11,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Changed
 
 ### Fixed
+- Fixed container to properly resolve async `.toService` bindings.
 
 ## [6.1.4]
 

src/syntax/binding_to_syntax.ts

@@ -116,9 +116,14 @@ class BindingToSyntax<T> implements interfaces.BindingToSyntax<T> {
   }
 
   public toService(service: interfaces.ServiceIdentifier<T>): void {
-    this.toDynamicValue((context: interfaces.Context) =>
-      context.container.get<T>(service),
-    );
+    this.toDynamicValue((context: interfaces.Context): T | Promise<T> => {
+      try {
+        return context.container.get<T>(service);
+      } catch (_error: unknown) {
+        // This is a performance degradation in this edge case, we do need to improve the internal resolution architecture in order to solve this properly.
+        return context.container.getAsync<T>(service);
+      }
+    });
   }
 }
 

test/bugs/issue_1564.test.ts

@@ -0,0 +1,46 @@
+import { expect } from 'chai';
+import { describe, it } from 'mocha';
+
+import { Container, inject, injectable } from '../../src/inversify';
+
+describe('Issue 1564', () => {
+  it('should not throw on getting async services bound using "toService"', async () => {
+    @injectable()
+    class Database {
+      constructor() {
+        console.log('new Database');
+      }
+    }
+
+    @injectable()
+    class Service1 {
+      constructor(@inject(Database) public database: Database) {
+        console.log('new Service1');
+      }
+    }
+
+    @injectable()
+    class Service2 {
+      constructor(@inject(Service1) public service1: Service1) {
+        console.log('new Service2');
+      }
+    }
+
+    const container: Container = new Container({ defaultScope: 'Request' });
+
+    container.bind(Database).toDynamicValue(async () => {
+      console.log('connecting to db...');
+      return new Database();
+    });
+
+    container.bind(Service1).toSelf();
+    container.bind(Service2).toSelf();
+
+    container.bind('services').toService(Service1);
+    container.bind('services').toService(Service2);
+
+    const result: unknown[] = await container.getAllAsync('services');
+
+    expect(result).to.have.length(2);
+  });
+});