diff --git a/app/models/type.rb b/app/models/type.rb
index 0117f8aaa6b8..9cd0ee07ef88 100644
--- a/app/models/type.rb
+++ b/app/models/type.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 #-- copyright
 # OpenProject is an open source project management software.
 # Copyright (C) the OpenProject GmbH
@@ -34,10 +36,12 @@ class Type < ApplicationRecord
 
   include ::Scopes::Scoped
 
-  attribute :patterns, Types::PatternCollectionType.new
+  attribute :patterns, Types::Patterns::CollectionType.new
 
   before_destroy :check_integrity
 
+  belongs_to :color, optional: true, class_name: "Color"
+
   has_many :work_packages
   has_many :workflows, dependent: :delete_all do
     def copy_from_type(source_type)
@@ -52,12 +56,9 @@ def copy_from_type(source_type)
                           join_table: "#{table_name_prefix}custom_fields_types#{table_name_suffix}",
                           association_foreign_key: "custom_field_id"
 
-  belongs_to :color, optional: true, class_name: "Color"
-
   acts_as_list
 
   validates :name, presence: true, uniqueness: { case_sensitive: false }, length: { maximum: 255 }
-
   validates :is_default, :is_milestone, inclusion: { in: [true, false] }
 
   scopes :milestone
@@ -65,8 +66,9 @@ def copy_from_type(source_type)
   default_scope { order("position ASC") }
 
   scope :without_standard, -> { where(is_standard: false).order(:position) }
+  scope :default, -> { where(is_default: true) }
 
-  def to_s; name end
+  delegate :to_s, to: :name
 
   def <=>(other)
     name <=> other.name
@@ -81,26 +83,20 @@ def self.statuses(types)
   end
 
   def self.standard_type
-    ::Type.where(is_standard: true).first
-  end
-
-  def self.default
-    ::Type.where(is_default: true)
+    where(is_standard: true).first
   end
 
   def self.enabled_in(project)
-    ::Type.includes(:projects).where(projects: { id: project })
+    includes(:projects).where(projects: { id: project })
   end
 
   def statuses(include_default: false)
     if new_record?
       Status.none
     elsif include_default
-      ::Type
-        .statuses([id])
-        .or(Status.where_default)
+      self.class.statuses([id]).or(Status.where_default)
     else
-      ::Type.statuses([id])
+      self.class.statuses([id])
     end
   end
 
@@ -108,9 +104,24 @@ def enabled_in?(object)
     object.types.include?(self)
   end
 
+  def replacement_patterns_defined?
+    return false if patterns.blank?
+
+    patterns.all_enabled.any?
+  end
+
+  def enabled_patterns
+    return {} if patterns.blank?
+
+    patterns.all_enabled
+  end
+
   private
 
   def check_integrity
-    raise "Can't delete type" if WorkPackage.where(type_id: id).any?
+    throw :abort if is_standard?
+    throw :abort if WorkPackage.exists?(type_id: id)
+
+    true
   end
 end
diff --git a/app/models/types/pattern.rb b/app/models/types/pattern.rb
index 62dcbd2b2c18..8442fcac254f 100644
--- a/app/models/types/pattern.rb
+++ b/app/models/types/pattern.rb
@@ -30,9 +30,10 @@
 
 module Types
   Pattern = Data.define(:blueprint, :enabled) do
-    def call(object)
-      # calculate string using object
-      blueprint.to_s + object.to_s
+    def enabled? = !!enabled
+
+    def resolve(work_package)
+      PatternMapper.new(self).resolve(work_package)
     end
 
     def to_h
diff --git a/app/models/types/pattern_mapper.rb b/app/models/types/pattern_mapper.rb
index 4db11198104c..b96399e54e88 100644
--- a/app/models/types/pattern_mapper.rb
+++ b/app/models/types/pattern_mapper.rb
@@ -1,40 +1,77 @@
 # frozen_string_literal: true
 
 #-- copyright
+# OpenProject is an open source project management software.
+# Copyright (C) the OpenProject GmbH
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License version 3.
+#
+# OpenProject is a fork of ChiliProject, which is a fork of Redmine. The copyright follows:
+# Copyright (C) 2006-2013 Jean-Philippe Lang
+# Copyright (C) 2010-2013 the ChiliProject Team
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+#
+# See COPYRIGHT and LICENSE files for more details.
 #++
 
 module Types
   class PatternMapper
-    TOKEN_REGEX = /{{[A-z_]+}}/
+    TOKEN_REGEX = /{{[0-9A-z_]+}}/
 
     MAPPING = {
-      assignee: ->(wp) { wp.assigned_to.name },
+      type: ->(wp) { wp.type.name },
+      assignee: ->(wp) { wp.assigned_to&.name },
       created: ->(wp) { wp.created_at },
-      author: ->(wp) { wp.author.name }
+      author: ->(wp) { wp.author.name },
+      parent_id: ->(wp) { wp.parent&.id },
+      project_name: ->(wp) { wp.project.name }
     }.freeze
 
     private_constant :MAPPING
 
     def initialize(pattern)
       @pattern = pattern
-      @tokens = pattern.scan(TOKEN_REGEX).map { |token| Patterns::Token.new(token) }
+      @tokens = pattern.scan(TOKEN_REGEX).map { |token| Patterns::Token.build(token) }
     end
 
     def valid?(work_package)
-      @tokens.each { |token| fn(token.key).call(work_package) }
+      @tokens.each { |token| get_value(work_package, token) }
     rescue NoMethodError
       false
     end
 
     def resolve(work_package)
       @tokens.inject(@pattern) do |pattern, token|
-        value = fn(token.key).call(work_package)
-        pattern.gsub(token.pattern, stringify(value))
+        pattern.gsub(token.pattern, get_value(work_package, token))
       end
     end
 
     private
 
+    def get_value(work_package, token)
+      raw_value = if token.custom_field? && token.context != work_package.context
+                    fn(key).call(work_package.public_send(token.context))
+                  else
+                    fn(token.key).call(work_package)
+                  end
+
+      stringify(raw_value)
+    end
+
     def fn(key)
       MAPPING.fetch(key) { ->(wp) { wp.public_send(key.to_sym) } }
     end
@@ -43,6 +80,8 @@ def stringify(value)
       case value
       when Date, Time, DateTime
         value.strftime("%Y-%m-%d")
+      when NilClass
+        "PITY DA FOOL!"
       else
         value.to_s
       end
diff --git a/app/models/types/pattern_collection.rb b/app/models/types/patterns/collection.rb
similarity index 66%
rename from app/models/types/pattern_collection.rb
rename to app/models/types/patterns/collection.rb
index 52a6dda2e459..990a7b9413c6 100644
--- a/app/models/types/pattern_collection.rb
+++ b/app/models/types/patterns/collection.rb
@@ -29,25 +29,31 @@
 #++
 
 module Types
-  PatternCollection = Data.define(:patterns) do
-    private_class_method :new
+  module Patterns
+    Collection = Data.define(:patterns) do
+      private_class_method :new
 
-    def self.build(patterns:, contract: PatternCollectionContract.new)
-      contract.call(patterns).to_monad.fmap { |success| new(success.to_h) }
-    end
+      def self.build(patterns:, contract: CollectionContract.new)
+        contract.call(patterns).to_monad.fmap { |success| new(success.to_h) }
+      end
 
-    def initialize(patterns:)
-      transformed = patterns.transform_values { Pattern.new(**_1) }.freeze
+      def initialize(patterns:)
+        transformed = patterns.transform_values { Pattern.new(**_1) }.freeze
 
-      super(patterns: transformed)
-    end
+        super(patterns: transformed)
+      end
 
-    def [](value)
-      patterns.fetch(value)
-    end
+      def all_enabled
+        patterns.select { |_, pattern| pattern.enabled? }
+      end
+
+      def [](value)
+        patterns.fetch(value)
+      end
 
-    def to_h
-      patterns.stringify_keys.transform_values(&:to_h)
+      def to_h
+        patterns.stringify_keys.transform_values(&:to_h)
+      end
     end
   end
 end
diff --git a/app/models/types/pattern_collection_contract.rb b/app/models/types/patterns/collection_contract.rb
similarity index 84%
rename from app/models/types/pattern_collection_contract.rb
rename to app/models/types/patterns/collection_contract.rb
index 2a8e7c16a1e1..02f79b288e4e 100644
--- a/app/models/types/pattern_collection_contract.rb
+++ b/app/models/types/patterns/collection_contract.rb
@@ -29,11 +29,13 @@
 #++
 
 module Types
-  class PatternCollectionContract < Dry::Validation::Contract
-    params do
-      required(:subject).hash do
-        required(:blueprint).filled(:string)
-        required(:enabled).filled(:bool)
+  module Patterns
+    class CollectionContract < Dry::Validation::Contract
+      params do
+        required(:subject).hash do
+          required(:blueprint).filled(:string)
+          required(:enabled).filled(:bool)
+        end
       end
     end
   end
diff --git a/app/models/types/pattern_collection_type.rb b/app/models/types/patterns/collection_type.rb
similarity index 73%
rename from app/models/types/pattern_collection_type.rb
rename to app/models/types/patterns/collection_type.rb
index 9758ee50c339..932cf17ec335 100644
--- a/app/models/types/pattern_collection_type.rb
+++ b/app/models/types/patterns/collection_type.rb
@@ -29,26 +29,28 @@
 #++
 
 module Types
-  class PatternCollectionType < ActiveModel::Type::Value
-    def assert_valid_value(value)
-      cast(value)
-    end
+  module Patterns
+    class CollectionType < ActiveModel::Type::Value
+      def assert_valid_value(value)
+        cast(value)
+      end
 
-    def cast(value)
-      PatternCollection.build(patterns: value).value_or { nil }
-    end
+      def cast(value)
+        Collection.build(patterns: value).value_or { nil }
+      end
 
-    def serialize(pattern)
-      return super if pattern.nil?
+      def serialize(pattern)
+        return super if pattern.nil?
 
-      YAML.dump(pattern.to_h)
-    end
+        YAML.dump(pattern.to_h)
+      end
 
-    def deserialize(value)
-      return if value.blank?
+      def deserialize(value)
+        return if value.blank?
 
-      data = YAML.safe_load(value)
-      cast(data)
+        data = YAML.safe_load(value)
+        cast(data)
+      end
     end
   end
 end
diff --git a/app/models/types/patterns/token.rb b/app/models/types/patterns/token.rb
index 1ae8ff88b4f5..ee525794cc55 100644
--- a/app/models/types/patterns/token.rb
+++ b/app/models/types/patterns/token.rb
@@ -1,12 +1,56 @@
 # frozen_string_literal: true
 
 #-- copyright
+# OpenProject is an open source project management software.
+# Copyright (C) the OpenProject GmbH
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License version 3.
+#
+# OpenProject is a fork of ChiliProject, which is a fork of Redmine. The copyright follows:
+# Copyright (C) 2006-2013 Jean-Philippe Lang
+# Copyright (C) 2010-2013 the ChiliProject Team
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+#
+# See COPYRIGHT and LICENSE files for more details.
 #++
 
 module Types
   module Patterns
-    Token = Data.define(:pattern) do
-      def key = pattern.tr("{}", "").to_sym
+    Token = Data.define(:pattern, :key) do
+      private_class_method :new
+
+      def self.build(pattern)
+        new(pattern, pattern.tr("{}", "").to_sym)
+      end
+
+      def custom_field? = key.include?("custom_field")
+
+      def custom_field_id
+        return nil unless custom_field?
+
+        Integer(key.to_s.gsub(/\D+/, ""))
+      end
+
+      def custom_field_context
+        context = key.to_s.gsub(/_?custom_field_\d+/, "")
+        return :work_package if context.blank?
+
+        context.to_sym
+      end
     end
   end
 end
diff --git a/app/services/work_packages/create_service.rb b/app/services/work_packages/create_service.rb
index 600c0f5d0eb2..405b863a72fb 100644
--- a/app/services/work_packages/create_service.rb
+++ b/app/services/work_packages/create_service.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 #-- copyright
 # OpenProject is an open source project management software.
 # Copyright (C) the OpenProject GmbH
@@ -30,17 +32,14 @@ class WorkPackages::CreateService < BaseServices::BaseCallable
   include ::WorkPackages::Shared::UpdateAncestors
   include ::Shared::ServiceContext
 
-  attr_accessor :user,
-                :contract_class
+  attr_reader :user, :contract_class
 
   def initialize(user:, contract_class: WorkPackages::CreateContract)
-    self.user = user
-    self.contract_class = contract_class
+    @user = user
+    @contract_class = contract_class
   end
 
-  def perform(work_package: WorkPackage.new,
-              send_notifications: nil,
-              **attributes)
+  def perform(work_package: WorkPackage.new, send_notifications: nil, **attributes)
     in_user_context(send_notifications:) do
       create(attributes, work_package)
     end
@@ -55,6 +54,8 @@ def create(attributes, work_package)
       if result.success
         work_package.attachments = work_package.attachments_replacements if work_package.attachments_replacements
         work_package.save
+        set_templated_subject(work_package)
+        work_package.save
       else
         false
       end
@@ -74,18 +75,19 @@ def create(attributes, work_package)
     result
   end
 
-  def set_attributes(attributes, wp)
-    attributes_service_class
-      .new(user:,
-           model: wp,
-           contract_class:)
-      .call(attributes)
+  def set_templated_subject(work_package)
+    return unless work_package.type&.replacement_patterns_defined?
+    return unless work_package.type.enabled_patterns[:subject]
+
+    work_package.subject = work_package.type.enabled_patterns[:subject].resolve(work_package)
+  end
+
+  def set_attributes(attributes, work_package)
+    attributes_service_class.new(user:, model: work_package, contract_class:).call(attributes)
   end
 
   def reschedule_related(work_package)
-    result = WorkPackages::SetScheduleService
-               .new(user:, work_package:)
-               .call
+    result = WorkPackages::SetScheduleService.new(user:, work_package:).call
 
     result.self_and_dependent.each do |r|
       unless r.result.save
@@ -100,9 +102,7 @@ def reschedule_related(work_package)
   def set_user_as_watcher(work_package)
     # We don't care if it fails here. If it does
     # the user simply does not become watcher
-    Services::CreateWatcher
-      .new(work_package, user)
-      .run(send_notifications: false)
+    Services::CreateWatcher.new(work_package, user).run(send_notifications: false)
   end
 
   def attributes_service_class
diff --git a/app/services/work_packages/set_attributes_service.rb b/app/services/work_packages/set_attributes_service.rb
index cd1118d965af..264cdeb57b1b 100644
--- a/app/services/work_packages/set_attributes_service.rb
+++ b/app/services/work_packages/set_attributes_service.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 #-- copyright
 # OpenProject is an open source project management software.
 # Copyright (C) the OpenProject GmbH
@@ -43,6 +45,15 @@ def set_attributes(attributes)
     end
 
     set_custom_attributes(attributes)
+    mark_templated_subject
+  end
+
+  def mark_templated_subject
+    return true unless work_package.type&.replacement_patterns_defined?
+
+    if work_package.type.patterns.all_enabled[:subject]
+      work_package.subject = "Templated by #{work_package.type.name}"
+    end
   end
 
   def set_static_attributes(attributes)
@@ -298,15 +309,14 @@ def derive_progress_values_class
 
   def set_version_to_nil
     if work_package.version &&
-      work_package.project &&
-      work_package.project.shared_versions.exclude?(work_package.version)
+       work_package.project&.shared_versions&.exclude?(work_package.version)
       work_package.version = nil
     end
   end
 
   def set_parent_to_nil
     if !Setting.cross_project_work_package_relations? &&
-      !work_package.parent_changed?
+       !work_package.parent_changed?
 
       work_package.parent = nil
     end
@@ -368,7 +378,7 @@ def new_start_date
 
   def new_start_date_from_parent
     return unless work_package.parent_id_changed? &&
-      work_package.parent
+                  work_package.parent
 
     work_package.parent.soonest_start
   end
diff --git a/app/services/work_packages/update_service.rb b/app/services/work_packages/update_service.rb
index 4788e7374239..ee45cd51626b 100644
--- a/app/services/work_packages/update_service.rb
+++ b/app/services/work_packages/update_service.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 #-- copyright
 # OpenProject is an open source project management software.
 # Copyright (C) the OpenProject GmbH
@@ -39,7 +41,16 @@ def initialize(user:, model:, contract_class: nil, contract_options: {}, cause_o
 
   private
 
+  def set_templated_attributes
+    return unless model.type.replacement_patterns_defined?
+
+    model.type.patterns.all_enabled.each do |key, pattern|
+      model.public_send(:"#{key}=", pattern.resolve(model))
+    end
+  end
+
   def after_perform(service_call)
+    set_templated_attributes
     update_related_work_packages(service_call)
     cleanup(service_call.result)
 
diff --git a/spec/factories/type_factory.rb b/spec/factories/type_factory.rb
index 180fe4db92ae..27c3beb06ce5 100644
--- a/spec/factories/type_factory.rb
+++ b/spec/factories/type_factory.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 #-- copyright
 # OpenProject is an open source project management software.
 # Copyright (C) the OpenProject GmbH
@@ -31,6 +33,7 @@
     sequence(:position)
     name { |a| "Type No. #{a.position}" }
     description { nil }
+    patterns { nil }
     created_at { Time.zone.now }
     updated_at { Time.zone.now }
 
diff --git a/spec/models/type_spec.rb b/spec/models/type_spec.rb
index 7f4073acc72c..7a1e0d25dd67 100644
--- a/spec/models/type_spec.rb
+++ b/spec/models/type_spec.rb
@@ -140,7 +140,7 @@
                       subject: { blueprint: "{{work_package:custom_field_123}} - {{project:custom_field_321}}", enabled: true }
                     })
 
-      expect(type.patterns).to be_a(Types::PatternCollection)
+      expect(type.patterns).to be_a(Types::Patterns::Collection)
       expect(type.patterns[:subject])
         .to eq(Types::Pattern.new("{{work_package:custom_field_123}} - {{project:custom_field_321}}", true))
     end
@@ -161,7 +161,7 @@
     it "converts the incoming hash into a PatternCollection" do
       type.patterns = { subject: { blueprint: "some_string", enabled: false } }
 
-      expect(type.patterns).to be_a(Types::PatternCollection)
+      expect(type.patterns).to be_a(Types::Patterns::Collection)
       expect(type.patterns[:subject]).to be_a(Types::Pattern)
 
       expect { type.save! }.not_to raise_error
diff --git a/spec/services/work_packages/set_attributes_service_spec.rb b/spec/services/work_packages/set_attributes_service_spec.rb
index 0915781acf4e..bfdbc1b92735 100644
--- a/spec/services/work_packages/set_attributes_service_spec.rb
+++ b/spec/services/work_packages/set_attributes_service_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 #-- copyright
 # OpenProject is an open source project management software.
 # Copyright (C) the OpenProject GmbH
@@ -43,6 +45,7 @@
 
     p
   end
+
   let(:work_package) do
     wp = build_stubbed(:work_package, project:, status: status_0_pct_complete)
     wp.type = initial_type
@@ -50,9 +53,7 @@
 
     wp
   end
-  let(:new_work_package) do
-    WorkPackage.new
-  end
+  let(:new_work_package) { WorkPackage.new }
   let(:initial_type) { build_stubbed(:type) }
   let(:milestone_type) { build_stubbed(:type_milestone) }
   let(:statuses) { [] }
@@ -78,24 +79,25 @@
   end
 
   shared_examples_for "service call" do |description: nil|
-    subject do
-      allow(work_package)
-        .to receive(:save)
+    subject(:service_result) { instance.call(call_attributes) }
 
-      instance.call(call_attributes)
-    end
+    before { allow(work_package).to receive(:save) }
 
     it description || "sets the value" do
       all_expected_attributes = {}
       all_expected_attributes.merge!(expected_attributes) if defined?(expected_attributes)
+
       if defined?(expected_kept_attributes)
         kept = work_package.attributes.slice(*expected_kept_attributes)
+
         if kept.size != expected_kept_attributes.size
           raise ArgumentError, "expected_kept_attributes contains attributes that are not present in the work_package: " \
                                "#{expected_kept_attributes - kept.keys} not present in #{work_package.attributes}"
         end
+
         all_expected_attributes.merge!(kept)
       end
+
       next if all_expected_attributes.blank?
 
       subject
@@ -354,9 +356,7 @@
     let(:new_statuses) { [other_status, default_status] }
 
     before do
-      allow(Status)
-        .to receive(:default)
-              .and_return(default_status)
+      allow(Status).to receive(:default).and_return(default_status)
     end
 
     context "with no value set before for a new work package" do
@@ -364,9 +364,7 @@
       let(:expected_attributes) { { status: default_status } }
       let(:work_package) { new_work_package }
 
-      before do
-        work_package.status = nil
-      end
+      before { work_package.status = nil }
 
       it_behaves_like "service call"
     end
@@ -447,17 +445,15 @@
 
       it_behaves_like "service call" do
         it "sets the service's author" do
-          subject
+          instance.call(call_attributes)
 
-          expect(work_package.author)
-            .to eql user
+          expect(work_package.author).to eql user
         end
 
         it "notes the author to be system changed" do
           subject
 
-          expect(work_package.changed_by_system["author_id"])
-            .to eql [nil, user.id]
+          expect(work_package.changed_by_system["author_id"]).to eql [nil, user.id]
         end
       end
     end
@@ -565,7 +561,7 @@
         before do
           allow(parent)
             .to receive(:soonest_start)
-                  .and_return(parent_start_date + 3.days)
+            .and_return(parent_start_date + 3.days)
         end
 
         it_behaves_like "service call" do
@@ -1475,10 +1471,10 @@
 
       allow(IssuePriority)
         .to receive(:active)
-              .and_return(scope)
+        .and_return(scope)
       allow(scope)
         .to receive(:default)
-              .and_return(default_priority)
+        .and_return(default_priority)
     end
 
     context "with no value set before for a new work package" do
@@ -1639,22 +1635,22 @@
       instance_double(ActiveRecord::Relation).tap do |categories_stub|
         allow(new_project)
           .to receive(:categories)
-                .and_return(categories_stub)
+          .and_return(categories_stub)
       end
     end
 
     before do
       without_partial_double_verification do
         allow(new_project_categories)
-        .to receive(:find_by)
-              .with(name: category.name)
-              .and_return nil
+          .to receive(:find_by)
+          .with(name: category.name)
+          .and_return nil
         allow(new_project)
           .to receive_messages(shared_versions: new_versions, types: new_types)
         allow(new_types)
           .to receive(:order)
-                .with(:position)
-                .and_return(new_types)
+          .with(:position)
+          .and_return(new_types)
       end
     end
 
@@ -1703,8 +1699,8 @@
           before do
             allow(new_project_categories)
               .to receive(:find_by)
-                    .with(name: category.name)
-                    .and_return new_category
+              .with(name: category.name)
+              .and_return new_category
           end
 
           it "uses the equally named category" do
@@ -1859,7 +1855,7 @@
 
       allow(wp)
         .to receive(:soonest_start)
-              .and_return(soonest_start)
+        .and_return(soonest_start)
 
       wp
     end
@@ -1940,7 +1936,7 @@
       before do
         allow(work_package)
           .to receive(:children)
-                .and_return([child])
+          .and_return([child])
       end
 
       context "when the child`s start date is after soonest_start" do
@@ -1968,4 +1964,33 @@
       end
     end
   end
+
+  context "when the type defines a pattern for an attribute" do
+    let(:type) { build_stubbed(:type, patterns: { subject: { blueprint: "{{type}} {{project_name}}", enabled: true } }) }
+    let(:work_package) { WorkPackage.new(type:) }
+
+    it "assigns a to be updated value to the field" do
+      instance.call({})
+
+      expect(work_package.subject).to eq("Templated by #{type.name}")
+    end
+
+    it "overrides even a passed subject" do
+      instance.call(subject: "I will be overwritten")
+
+      expect(work_package.subject).to eq("Templated by #{type.name}")
+    end
+
+    context "when the pattern is disabled" do
+      let(:type) do
+        build_stubbed(:type, patterns: { subject: { blueprint: "{{type}} {{project_name}}", enabled: false } })
+      end
+
+      it "does not overwrite the attribute" do
+        instance.call(subject: "I will be kept")
+
+        expect(work_package.subject).to eq("I will be kept")
+      end
+    end
+  end
 end