added error for relatedQueries ommiting 'for' outside subqueries (#1895)

lib/relations/RelationOwner.js

@@ -187,7 +187,10 @@ function isQueryBuilder(item) {
 
 function findFirstNonPartialAncestorQuery(builder) {
   builder = builder.parentQuery();
-
+  if (!builder)
+    throw Error(
+      'query method `for` ommitted outside a subquery, can not figure out relation target'
+    );
   while (builder.isPartial()) {
     if (!builder.parentQuery()) {
       break;

tests/integration/misc/relatedQueryErrors.js

@@ -0,0 +1,78 @@
+const { expect } = require('chai');
+const { Model } = require('../../../');
+
+module.exports = session => {
+  describe('model relatedQueries fail when they lack a proper target', () => {
+    let knex = session.knex;
+
+    class Post extends Model {
+      static get tableName() {
+        return 'posts';
+      }
+    }
+
+    class User extends Model {
+      static get tableName() {
+        return 'users';
+      }
+      static get relationMappings() {
+        return {
+          posts: {
+            modelClass: Post,
+            relation: Model.HasManyRelation,
+            join: {
+              from: 'users.id',
+              to: 'posts.user_id'
+            }
+          }
+        };
+      }
+    }
+
+    before(async () => {
+      const knex = session.knex;
+
+      await knex.schema.dropTableIfExists('posts');
+      await knex.schema.dropTableIfExists('users');
+
+      await knex.schema
+        .createTable('users', table => {
+          table.increments('id').primary();
+          table.string('name');
+        })
+        .createTable('posts', table => {
+          table.increments('id').primary();
+          table
+            .integer('user_id')
+            .unsigned()
+            .references('id')
+            .inTable('users');
+          table.string('content');
+        });
+    });
+
+    after(async () => {
+      await knex.schema.dropTableIfExists('posts');
+      await knex.schema.dropTableIfExists('users');
+    });
+
+    it('relatedQuery insert does not silently fail when ommiting `for` a target', async () => {
+      try {
+        await User.relatedQuery('posts', knex).insert({ content: 'my post content' });
+      } catch (e) {
+        expect(e.message).to.equal(
+          'query method `for` ommitted outside a subquery, can not figure out relation target'
+        );
+      }
+    });
+    it('relatedQuery where fails when `for` is ommited and is not a subquery', async () => {
+      try {
+        await User.relatedQuery('posts', knex).where({ content: 'my post content' });
+      } catch (e) {
+        expect(e.message).to.equal(
+          'query method `for` ommitted outside a subquery, can not figure out relation target'
+        );
+      }
+    });
+  });
+};