#235 - Ensure reverse query set creations are scoped to the related r…

…ecord

docs/docs/models-and-databases/relationships.md

@@ -95,6 +95,10 @@ article_3 = Article.create!(title: "Third article", author: author_1)
 # List the first author's articles
 author_1.articles.to_a # [#<Article:0x1036e3ee0 id: 1, title: "First article", author_id: 1>,
                        #  #<Article:0x1036e3e70 id: 3, title: "Third article", author_id: 1>]
+
+# Create an article associated with the first author
+article_4 = author_1.articles.create!(title: "Fourth article")
+article_4.author # => #<Author:0x101590c40 id: 1, full_name: "Foo Bar">
 ```
 
 :::tip

spec/marten/db/query/related_set_spec.cr

@@ -15,4 +15,60 @@ describe Marten::DB::Query::RelatedSet do
       qset.all.to_set.should eq(Set{post_1, post_3})
     end
   end
+
+  describe "#create" do
+    it "creates a new record with the related field set" do
+      user = TestUser.create!(username: "jd1", email: "[email protected]", first_name: "John", last_name: "Doe")
+
+      qset = Marten::DB::Query::RelatedSet(Post).new(user, "author_id")
+
+      new_post = qset.create(title: "Post")
+
+      new_post.valid?.should be_true
+      new_post.persisted?.should be_true
+      new_post.author.should eq user
+    end
+
+    it "creates a new record with the related field set when a block is used" do
+      user = TestUser.create!(username: "jd1", email: "[email protected]", first_name: "John", last_name: "Doe")
+
+      qset = Marten::DB::Query::RelatedSet(Post).new(user, "author_id")
+
+      new_post = qset.create do |p|
+        p.title = "Post"
+      end
+
+      new_post.valid?.should be_true
+      new_post.persisted?.should be_true
+      new_post.author.should eq user
+    end
+  end
+
+  describe "#create!" do
+    it "creates a new record with the related field set" do
+      user = TestUser.create!(username: "jd1", email: "[email protected]", first_name: "John", last_name: "Doe")
+
+      qset = Marten::DB::Query::RelatedSet(Post).new(user, "author_id")
+
+      new_post = qset.create!(title: "Post")
+
+      new_post.valid?.should be_true
+      new_post.persisted?.should be_true
+      new_post.author.should eq user
+    end
+
+    it "creates a new record with the related field set when a block is used" do
+      user = TestUser.create!(username: "jd1", email: "[email protected]", first_name: "John", last_name: "Doe")
+
+      qset = Marten::DB::Query::RelatedSet(Post).new(user, "author_id")
+
+      new_post = qset.create! do |p|
+        p.title = "Post"
+      end
+
+      new_post.valid?.should be_true
+      new_post.persisted?.should be_true
+      new_post.author.should eq user
+    end
+  end
 end

src/marten/db/query/related_set.cr

@@ -15,6 +15,12 @@ module Marten
                    end
         end
 
+        protected def build_record(**kwargs)
+          record = M.new(**kwargs)
+          record.assign_related_object(@instance, @related_field_id)
+          record
+        end
+
         protected def clone(other_query = nil)
           RelatedSet(M).new(
             instance: @instance,

src/marten/db/query/set.cr

@@ -248,7 +248,7 @@ module Marten
         # query_set.create(title: "My blog post")
         # ```
         def create(**kwargs)
-          object = M.new(**kwargs)
+          object = build_record(**kwargs)
           object.save(using: @query.using)
           object
         end
@@ -266,7 +266,7 @@ module Marten
         # end
         # ```
         def create(**kwargs, &)
-          object = M.new(**kwargs)
+          object = build_record(**kwargs)
           yield object
           object.save(using: @query.using)
           object
@@ -283,7 +283,7 @@ module Marten
         # query_set.create!(title: "My blog post")
         # ```
         def create!(**kwargs)
-          object = M.new(**kwargs)
+          object = build_record(**kwargs)
           object.save!(using: @query.using)
           object
         end
@@ -301,7 +301,7 @@ module Marten
         # end
         # ```
         def create!(**kwargs, &)
-          object = M.new(**kwargs)
+          object = build_record(**kwargs)
           yield object
           object.save!(using: @query.using)
           object
@@ -1179,6 +1179,10 @@ module Marten
           {% end %}
         end
 
+        protected def build_record(**kwargs)
+          M.new(**kwargs)
+        end
+
         protected def clone(other_query = nil)
           Set(M).new(
             query: other_query.nil? ? @query.clone : other_query.not_nil!,