Handle composite primary keys in scopes

lib/pg_search/scope_options.rb

@@ -79,10 +79,15 @@ def increment_counter
     delegate :connection, :quoted_table_name, to: :model
 
     def subquery
-      model
-        .unscoped
-        .select("#{primary_key} AS pg_search_id")
-        .select("#{rank} AS rank")
+      query = model.unscoped
+
+      query = if composite_primary_key?
+        query.select(model.primary_key.map.with_index(1) { |part, index| "#{quoted_column_name(part)} AS pg_search_id_#{index}" })
+      else
+        query.select("#{primary_key} AS pg_search_id")
+      end
+
+      query.select("#{rank} AS rank")
         .joins(subquery_join)
         .where(conditions)
         .limit(nil)
@@ -101,12 +106,17 @@ def order_within_rank
     end
 
     def primary_key
-      "#{quoted_table_name}.#{connection.quote_column_name(model.primary_key)}"
+      if composite_primary_key?
+        model.primary_key.map { |part| quoted_column_name(part) }.join(",")
+      else
+        quoted_column_name(model.primary_key)
+      end
     end
 
     def subquery_join
       if config.associations.any?
         config.associations.map do |association|
+          # TODO: handle composite primary keys in associations
           association.join(primary_key)
         end.join(" ")
       end
@@ -142,7 +152,14 @@ def rank
     end
 
     def rank_join(rank_table_alias)
-      "INNER JOIN (#{subquery.to_sql}) AS #{rank_table_alias} ON #{primary_key} = #{rank_table_alias}.pg_search_id"
+      join_condition = if composite_primary_key?
+        model.primary_key.map.with_index(1) { |part, index| "#{quoted_column_name(part)} = #{rank_table_alias}.pg_search_id_#{index}" }
+          .join(" AND ")
+      else
+        "#{primary_key} = #{rank_table_alias}.pg_search_id"
+      end
+
+      "INNER JOIN (#{subquery.to_sql}) AS #{rank_table_alias} ON #{join_condition}"
     end
 
     def include_table_aliasing_for_rank(scope)
@@ -152,5 +169,13 @@ def include_table_aliasing_for_rank(scope)
         new_scope.instance_eval { extend PgSearchRankTableAliasing }
       end
     end
+
+    def composite_primary_key?
+      model.primary_key.is_a?(Array)
+    end
+
+    def quoted_column_name(column)
+      "#{quoted_table_name}.#{connection.quote_column_name(column)}"
+    end
   end
 end

spec/integration/composite_primary_key_spec.rb

@@ -0,0 +1,152 @@
+# frozen_string_literal: true
+
+require "spec_helper"
+
+describe "composite_primary_key" do
+  context 'without relations' do
+    with_model :Parent do
+      table primary_key: [:first_name, :last_name] do |t|
+        t.string :first_name
+        t.string :last_name
+        t.string :hobby
+      end
+
+      model do
+        include PgSearch::Model
+        self.primary_key = [:first_name, :last_name]
+        pg_search_scope :search_hobby, against: :hobby
+      end
+    end
+
+    before { Parent.create!(id: ["first_name", "last_name"], hobby: "golf") }
+    let!(:record_1) { Parent.create!(id: ["first_name_2", "last_name_2"], hobby: "basketball") }
+
+    it "searches without any issues" do
+      expect(Parent.search_hobby("basketball")).to eq([record_1])
+    end
+  end
+
+  context "without composite_primary_key, searching against relation with a composite_primary_key" do
+    with_model :Parent do
+      table primary_key: [:first_name, :last_name] do |t|
+        t.string :first_name
+        t.string :last_name
+        t.string :hobby
+      end
+
+      model do
+        include PgSearch::Model
+        has_many :children
+        self.primary_key = [:first_name, :last_name]
+      end
+    end
+
+    with_model :Child do
+      table do |t|
+        t.string :parent_first_name
+        t.string :parent_last_name
+      end
+
+      model do
+        include PgSearch::Model
+        belongs_to :parent, foreign_key: [:parent_first_name, :parent_last_name]
+
+        pg_search_scope :search_parent_hobby, associated_against: {
+          parent: [:hobby]
+        } 
+      end
+    end
+
+    before do
+      parent = Parent.create!(id: ["first_name", "last_name"], hobby: "golf")
+      Child.create!(parent: parent)
+    end
+
+    let!(:record_1) do
+      parent = Parent.create!(id: ["first_name_2", "last_name_2"], hobby: "basketball")
+      Child.create!(parent: parent)
+    end
+
+    it "searches without any issues" do
+      expect(Child.search_parent_hobby("basketball")).to eq([record_1])
+    end
+  end
+
+  context "with composite_primary_key, searching against relation with a composite_primary_key" do
+    with_model :Parent do
+      table primary_key: [:first_name, :last_name] do |t|
+        t.string :first_name
+        t.string :last_name
+        t.string :hobby
+      end
+
+      model do
+        include PgSearch::Model
+        has_many :children, foreign_key: [:first_name, :last_name]
+        self.primary_key = [:first_name, :last_name]
+      end
+    end
+
+    with_model :Child do
+      table primary_key: [:first_name, :last_name] do |t|
+        t.string :hobby
+        t.string :first_name
+        t.string :last_name
+        t.string :parent_first_name
+        t.string :parent_last_name
+      end
+
+      model do
+        include PgSearch::Model
+        belongs_to :parent, foreign_key: [:parent_first_name, :parent_last_name]
+        has_many :siblings, through: :parent, source: :children
+
+        pg_search_scope :search_parent_hobby, associated_against: {
+          parent: [:hobby]
+        } 
+
+        pg_search_scope :search_sibling_hobby, associated_against: {
+          siblings: [:hobby]
+        } 
+
+        pg_search_scope :search_hobby, associated_against: {
+          parent: [:hobby],
+          siblings: [:hobby]
+        }
+      end
+    end
+
+    before do
+      parent = Parent.create!(id: ["first_name", "last_name"], hobby: "golf")
+      Child.create!(id: ["first_name", "last_name"], parent: parent)
+    end
+
+    it "searches direct relation without any issues" do
+      parent = Parent.create!(id: ["first_name_2", "last_name_2"], hobby: "basketball")
+      record_1 = Child.create!(id: ["first_name_2", "last_name_2"], parent: parent)
+      expect(Child.search_parent_hobby("basketball")).to eq([record_1])
+    end
+
+    it "searches through relation without any issues" do
+      parent = Parent.create!(id: ["first_name_2", "last_name_2"], hobby: "juggling")
+      Child.create!(id: ["first_name_2", "last_name_2"], parent: parent, hobby: "basketball")
+      record_1 = Child.create!(id: ["first_name_3", "last_name_3"], parent: parent, hobby: "studying")
+
+      expect(Child.search_sibling_hobby("basketball")).to eq([record_1])
+    end
+
+    it "searches through multiple relations without any issues" do
+      parent_1 = Parent.create!(id: ["first_name_2", "last_name_2"], hobby: "basketball")
+      record_1 = Child.create!(id: ["first_name_2", "last_name_2"], parent: parent_1, hobby: "studying") # match by parent
+
+      parent_2 = Parent.create!(id: ["first_name_3", "last_name_3"], hobby: "juggling")
+      record_2 = Child.create!(id: ["first_name_3", "last_name_3"], parent: parent_2, hobby: "bowling") # match by sibling
+      record_3 = Child.create!(id: ["first_name_4", "last_name_4"], parent: parent_2, hobby: "basketball") # match by self
+
+      parent_3 = Parent.create!(id: ["first_name_4", "last_name_4"], hobby: "golf")
+      Child.create!(id: ["first_name_5", "last_name_5"], parent: parent_3, hobby: "sleeping") 
+
+      expect(Child.search_hobby("basketball")).to eq([record_1, record_2, record_3])
+    end
+  end
+end