13 files changed, 92 insertions, 15 deletions

diff --git a/app/finders/labels_finder.rb b/app/finders/labels_finder.rb
index e523942ea4c..027cdc4fc78 100644
--- a/app/finders/labels_finder.rb
+++ b/app/finders/labels_finder.rb
@@ -51,7 +51,7 @@ class LabelsFinder < UnionFinder
       end
 
       label_ids << Label.where(group_id: projects.group_ids)
-      label_ids << Label.where(project_id: projects.select(:id)) unless only_group_labels?
+      label_ids << Label.where(project_id: ids_user_can_read_labels(projects)) unless only_group_labels?
     end
 
     label_ids
@@ -188,4 +188,10 @@ class LabelsFinder < UnionFinder
       groups.select { |group| authorized_to_read_labels?(group) }
     end
   end
+
+  # rubocop: disable CodeReuse/ActiveRecord
+  def ids_user_can_read_labels(projects)
+    Project.where(id: projects.select(:id)).ids_with_issuables_available_for(current_user)
+  end
+  # rubocop: enable CodeReuse/ActiveRecord
 end
diff --git a/app/graphql/gitlab_schema.rb b/app/graphql/gitlab_schema.rb
index 4c8612c8f2e..1899278ff3c 100644
--- a/app/graphql/gitlab_schema.rb
+++ b/app/graphql/gitlab_schema.rb
@@ -18,15 +18,15 @@ class GitlabSchema < GraphQL::Schema
   use Gitlab::Graphql::GenericTracing
 
   query_analyzer Gitlab::Graphql::QueryAnalyzers::LoggerAnalyzer.new
-
-  query(Types::QueryType)
-
-  default_max_page_size 100
+  query_analyzer Gitlab::Graphql::QueryAnalyzers::RecursionAnalyzer.new
 
   max_complexity DEFAULT_MAX_COMPLEXITY
   max_depth DEFAULT_MAX_DEPTH
 
-  mutation(Types::MutationType)
+  query Types::QueryType
+  mutation Types::MutationType
+
+  default_max_page_size 100
 
   class << self
     def multiplex(queries, **kwargs)
diff --git a/app/models/concerns/mentionable/reference_regexes.rb b/app/models/concerns/mentionable/reference_regexes.rb
index fec31cd262b..f44a674b3c9 100644
--- a/app/models/concerns/mentionable/reference_regexes.rb
+++ b/app/models/concerns/mentionable/reference_regexes.rb
@@ -13,7 +13,9 @@ module Mentionable
     def self.other_patterns
       [
         Commit.reference_pattern,
-        MergeRequest.reference_pattern
+        MergeRequest.reference_pattern,
+        Label.reference_pattern,
+        Milestone.reference_pattern
       ]
     end
 
diff --git a/app/models/discussion.rb b/app/models/discussion.rb
index 0d066d0d99f..b8525f7b135 100644
--- a/app/models/discussion.rb
+++ b/app/models/discussion.rb
@@ -16,6 +16,7 @@ class Discussion
             :commit_id,
             :for_commit?,
             :for_merge_request?,
+            :noteable_ability_name,
             :to_ability_name,
             :editable?,
             :visible_for?,
diff --git a/app/models/member.rb b/app/models/member.rb
index e2d26773d45..2654453cf3f 100644
--- a/app/models/member.rb
+++ b/app/models/member.rb
@@ -8,6 +8,7 @@ class Member < ApplicationRecord
   include Gitlab::Access
   include Presentable
   include Gitlab::Utils::StrongMemoize
+  include FromUnion
 
   attr_accessor :raw_invite_token
 
diff --git a/app/models/milestone.rb b/app/models/milestone.rb
index 2fa0cfc9b93..a9f4cdec901 100644
--- a/app/models/milestone.rb
+++ b/app/models/milestone.rb
@@ -261,6 +261,10 @@ class Milestone < ApplicationRecord
     group || project
   end
 
+  def to_ability_name
+    model_name.singular
+  end
+
   def group_milestone?
     group_id.present?
   end
diff --git a/app/models/note.rb b/app/models/note.rb
index 43f349c6fa2..ce60413b8a0 100644
--- a/app/models/note.rb
+++ b/app/models/note.rb
@@ -361,6 +361,10 @@ class Note < ApplicationRecord
   end
 
   def to_ability_name
+    model_name.singular
+  end
+
+  def noteable_ability_name
     for_snippet? ? noteable.class.name.underscore : noteable_type.demodulize.underscore
   end
 
diff --git a/app/models/project.rb b/app/models/project.rb
index 3525f37f8d5..74da042d5a5 100644
--- a/app/models/project.rb
+++ b/app/models/project.rb
@@ -609,11 +609,11 @@ class Project < ApplicationRecord
       joins(:namespace).where(namespaces: { type: 'Group' }).select(:namespace_id)
     end
 
-    # Returns ids of projects with milestones available for given user
+    # Returns ids of projects with issuables available for given user
     #
-    # Used on queries to find milestones which user can see
-    # For example: Milestone.where(project_id: ids_with_milestone_available_for(user))
-    def ids_with_milestone_available_for(user)
+    # Used on queries to find milestones or labels which user can see
+    # For example: Milestone.where(project_id: ids_with_issuables_available_for(user))
+    def ids_with_issuables_available_for(user)
       with_issues_enabled = with_issues_available_for_user(user).select(:id)
       with_merge_requests_enabled = with_merge_requests_available_for_user(user).select(:id)
 
@@ -1260,6 +1260,10 @@ class Project < ApplicationRecord
     end
   end
 
+  def to_ability_name
+    model_name.singular
+  end
+
   # rubocop: disable CodeReuse/ServiceClass
   def execute_hooks(data, hooks_scope = :push_hooks)
     run_after_commit_or_now do
diff --git a/app/models/system_note_metadata.rb b/app/models/system_note_metadata.rb
index 11cbeb60bba..5a44ee7211b 100644
--- a/app/models/system_note_metadata.rb
+++ b/app/models/system_note_metadata.rb
@@ -10,6 +10,7 @@ class SystemNoteMetadata < ApplicationRecord
     commit cross_reference
     close duplicate
     moved merge
+    label milestone
   ].freeze
 
   ICON_TYPES = %w[
diff --git a/app/policies/commit_policy.rb b/app/policies/commit_policy.rb
index 4d4f0ba9267..4b358c45ec2 100644
--- a/app/policies/commit_policy.rb
+++ b/app/policies/commit_policy.rb
@@ -4,4 +4,5 @@ class CommitPolicy < BasePolicy
   delegate { @subject.project }
 
   rule { can?(:download_code) }.enable :read_commit
+  rule { ~can?(:read_commit) }.prevent :create_note
 end
diff --git a/app/policies/note_policy.rb b/app/policies/note_policy.rb
index b2af6c874c7..dcde8cefa0d 100644
--- a/app/policies/note_policy.rb
+++ b/app/policies/note_policy.rb
@@ -9,7 +9,7 @@ class NotePolicy < BasePolicy
 
   condition(:editable, scope: :subject) { @subject.editable? }
 
-  condition(:can_read_noteable) { can?(:"read_#{@subject.to_ability_name}") }
+  condition(:can_read_noteable) { can?(:"read_#{@subject.noteable_ability_name}") }
 
   condition(:is_visible) { @subject.visible_for?(@user) }
 
diff --git a/app/services/notification_service.rb b/app/services/notification_service.rb
index b56b2cf14e3..1709474a6c7 100644
--- a/app/services/notification_service.rb
+++ b/app/services/notification_service.rb
@@ -281,7 +281,7 @@ class NotificationService
   end
 
   def send_new_note_notifications(note)
-    notify_method = "note_#{note.to_ability_name}_email".to_sym
+    notify_method = "note_#{note.noteable_ability_name}_email".to_sym
 
     recipients = NotificationRecipientService.build_new_note_recipients(note)
     recipients.each do |recipient|
diff --git a/app/services/projects/participants_service.rb b/app/services/projects/participants_service.rb
index 7080f388e53..1cd81fe37c7 100644
--- a/app/services/projects/participants_service.rb
+++ b/app/services/projects/participants_service.rb
@@ -7,16 +7,69 @@ module Projects
     def execute(noteable)
       @noteable = noteable
 
-      participants = noteable_owner + participants_in_noteable + all_members + groups + project_members
+      participants =
+        noteable_owner +
+        participants_in_noteable +
+        all_members +
+        groups +
+        project_members
+
       participants.uniq
     end
 
     def project_members
-      @project_members ||= sorted(project.team.members)
+      @project_members ||= sorted(get_project_members)
+    end
+
+    def get_project_members
+      members = Member.from_union([project_members_through_ancestral_groups,
+                                   project_members_through_invited_groups,
+                                   individual_project_members])
+
+      User.id_in(members.select(:user_id))
     end
 
     def all_members
       [{ username: "all", name: "All Project and Group Members", count: project_members.count }]
     end
+
+    private
+
+    def project_members_through_invited_groups
+      groups_with_ancestors_ids = Gitlab::ObjectHierarchy
+        .new(visible_groups)
+        .base_and_ancestors
+        .pluck_primary_key
+
+      GroupMember
+        .active_without_invites_and_requests
+        .with_source_id(groups_with_ancestors_ids)
+    end
+
+    def visible_groups
+      visible_groups = project.invited_groups
+
+      unless project_owner?
+        visible_groups = visible_groups.public_or_visible_to_user(current_user)
+      end
+
+      visible_groups
+    end
+
+    def project_members_through_ancestral_groups
+      project.group.present? ? project.group.members_with_parents : Member.none
+    end
+
+    def individual_project_members
+      project.project_members
+    end
+
+    def project_owner?
+      if project.group.present?
+        project.group.owners.include?(current_user)
+      else
+        project.namespace.owner == current_user
+      end
+    end
   end
 end