Model: fix eager-loaded relation loading from static query

src/orm/model/Model.ts

@@ -174,10 +174,24 @@ export abstract class Model<T extends Model<T>> extends AppClass implements Bus
             builder.field(field.databaseKey)
         })
 
-        for ( const relation of this.prototype.with ) {
-            // eslint-disable-next-line @typescript-eslint/ban-ts-comment
-            // @ts-ignore
-            builder.with(relation)
+        if ( Array.isArray(this.prototype.with) ) {
+            // Try to get the eager-loaded relations statically, if possible
+            for (const relation of this.prototype.with) {
+                // eslint-disable-next-line @typescript-eslint/ban-ts-comment
+                // @ts-ignore
+                builder.with(relation)
+            }
+        } else if ( this.constructor.length < 1 ) {
+            // Otherwise, if we can instantiate the model without any arguments,
+            // do that and get the eager-loaded relations directly.
+            const inst = Container.getContainer().make<Model<any>>(this)
+            if ( Array.isArray(inst.with) ) {
+                for (const relation of inst.with) {
+                    // eslint-disable-next-line @typescript-eslint/ban-ts-comment
+                    // @ts-ignore
+                    builder.with(relation)
+                }
+            }
         }
 
         builder.withScopes(this.prototype.scopes)