1 files changed, 42 insertions, 10 deletions
diff --git a/app/models/ci/runner.rb b/app/models/ci/runner.rb
index 530eacf4be0..57edd6a4956 100644
--- a/app/models/ci/runner.rb
+++ b/app/models/ci/runner.rb
@@ -12,9 +12,9 @@ module Ci
     FORM_EDITABLE = %i[description tag_list active run_untagged locked access_level maximum_timeout_human_readable].freeze
 
     has_many :builds
-    has_many :runner_projects, dependent: :destroy # rubocop:disable Cop/ActiveRecordDependent
+    has_many :runner_projects, inverse_of: :runner, dependent: :destroy # rubocop:disable Cop/ActiveRecordDependent
     has_many :projects, through: :runner_projects
-    has_many :runner_namespaces
+    has_many :runner_namespaces, inverse_of: :runner
     has_many :groups, through: :runner_namespaces
 
     has_one :last_build, ->() { order('id DESC') }, class_name: 'Ci::Build'
@@ -56,10 +56,15 @@ module Ci
     end
 
     validate :tag_constraints
-    validate :either_projects_or_group
     validates :access_level, presence: true
     validates :runner_type, presence: true
 
+    validate :no_projects, unless: :project_type?
+    validate :no_groups, unless: :group_type?
+    validate :any_project, if: :project_type?
+    validate :exactly_one_group, if: :group_type?
+    validate :validate_is_shared
+
     acts_as_taggable
 
     after_destroy :cleanup_runner_queue
@@ -115,8 +120,15 @@ module Ci
         raise ArgumentError, 'Transitioning a group runner to a project runner is not supported'
       end
 
-      self.save
-      project.runner_projects.create(runner_id: self.id)
+      begin
+        transaction do
+          self.projects << project
+          self.save!
+        end
+      rescue ActiveRecord::RecordInvalid => e
+        self.errors.add(:assign_to, e.message)
+        false
+      end
     end
 
     def display_name
@@ -253,13 +265,33 @@ module Ci
       self.class.owned_or_shared(project_id).where(id: self.id).any?
     end
 
-    def either_projects_or_group
-      if groups.many?
-        errors.add(:runner, 'can only be assigned to one group')
+    def no_projects
+      if projects.any?
+        errors.add(:runner, 'cannot have projects assigned')
+      end
+    end
+
+    def no_groups
+      if groups.any?
+        errors.add(:runner, 'cannot have groups assigned')
+      end
+    end
+
+    def any_project
+      unless projects.any?
+        errors.add(:runner, 'needs to be assigned to at least one project')
+      end
+    end
+
+    def exactly_one_group
+      unless groups.one?
+        errors.add(:runner, 'needs to be assigned to exactly one group')
       end
+    end
 
-      if assigned_to_group? && assigned_to_project?
-        errors.add(:runner, 'can only be assigned either to projects or to a group')
+    def validate_is_shared
+      unless is_shared? == instance_type?
+        errors.add(:is_shared, 'is not equal to instance_type?')
       end
     end