Add `to_reference` for models that support references

Now there is a single source of information for which attribute a model
uses to be referenced, and its special character.

10 files changed, 138 insertions, 16 deletions

diff --git a/app/models/commit.rb b/app/models/commit.rb
index 5dea7dda513..3cc8d11a4aa 100644
--- a/app/models/commit.rb
+++ b/app/models/commit.rb
@@ -1,9 +1,11 @@
 class Commit
-  include ActiveModel::Conversion
-  include StaticModel
   extend ActiveModel::Naming
+
+  include ActiveModel::Conversion
   include Mentionable
   include Participable
+  include Referable
+  include StaticModel
 
   attr_mentionable :safe_message
   participant :author, :committer, :notes, :mentioned_users
@@ -60,6 +62,14 @@ class Commit
     (self.class === other) && (raw == other.raw)
   end
 
+  def to_reference(from_project = nil)
+    if cross_project_reference?(from_project)
+      "#{project.to_reference}@#{id}"
+    else
+      id
+    end
+  end
+
   def diff_line_count
     @diff_line_count ||= Commit::diff_line_count(self.diffs)
     @diff_line_count
@@ -132,7 +142,7 @@ class Commit
 
   # Mentionable override.
   def gfm_reference
-    "commit #{id}"
+    "commit #{to_reference}"
   end
 
   def author
diff --git a/app/models/commit_range.rb b/app/models/commit_range.rb
index e6456198264..b98f939a115 100644
--- a/app/models/commit_range.rb
+++ b/app/models/commit_range.rb
@@ -19,6 +19,7 @@
 #
 class CommitRange
   include ActiveModel::Conversion
+  include Referable
 
   attr_reader :sha_from, :notation, :sha_to
 
@@ -59,6 +60,14 @@ class CommitRange
     "#{sha_from[0..7]}#{notation}#{sha_to[0..7]}"
   end
 
+  def to_reference(from_project = nil)
+    if cross_project_reference?(from_project)
+      "#{project.to_reference}@#{to_s}"
+    else
+      to_s
+    end
+  end
+
   # Returns a String for use in a link's title attribute
   def reference_title
     "Commits #{suffixed_sha_from} through #{sha_to}"
diff --git a/app/models/external_issue.rb b/app/models/external_issue.rb
index 85fdb12bfdc..6fda4a2ab77 100644
--- a/app/models/external_issue.rb
+++ b/app/models/external_issue.rb
@@ -1,4 +1,6 @@
 class ExternalIssue
+  include Referable
+
   def initialize(issue_identifier, project)
     @issue_identifier, @project = issue_identifier, project
   end
@@ -7,6 +9,10 @@ class ExternalIssue
     @issue_identifier.to_s
   end
 
+  def to_reference(_from_project = nil)
+    id
+  end
+
   def id
     @issue_identifier.to_s
   end
diff --git a/app/models/group.rb b/app/models/group.rb
index 687458adac4..33d72e0d9ee 100644
--- a/app/models/group.rb
+++ b/app/models/group.rb
@@ -17,6 +17,8 @@ require 'carrierwave/orm/activerecord'
 require 'file_size_validator'
 
 class Group < Namespace
+  include Referable
+
   has_many :group_members, dependent: :destroy, as: :source, class_name: 'GroupMember'
   has_many :users, through: :group_members
 
@@ -36,6 +38,14 @@ class Group < Namespace
     def sort(method)
       order_by(method)
     end
+
+    def reference_prefix
+      '@'
+    end
+  end
+
+  def to_reference(_from_project = nil)
+    "#{self.class.reference_prefix}#{name}"
   end
 
   def human_name
diff --git a/app/models/issue.rb b/app/models/issue.rb
index 6e102051387..ff13cbca845 100644
--- a/app/models/issue.rb
+++ b/app/models/issue.rb
@@ -21,10 +21,11 @@ require 'carrierwave/orm/activerecord'
 require 'file_size_validator'
 
 class Issue < ActiveRecord::Base
-  include Issuable
   include InternalId
-  include Taskable
+  include Issuable
+  include Referable
   include Sortable
+  include Taskable
 
   ActsAsTaggableOn.strict_case_match = true
 
@@ -49,14 +50,28 @@ class Issue < ActiveRecord::Base
     state :closed
   end
 
+  def self.reference_prefix
+    '#'
+  end
+
   def hook_attrs
     attributes
   end
 
+  def to_reference(from_project = nil)
+    reference = "#{self.class.reference_prefix}#{iid}"
+
+    if cross_project_reference?(from_project)
+      reference = project.to_reference + reference
+    end
+
+    reference
+  end
+
   # Mentionable overrides.
 
   def gfm_reference
-    "issue ##{iid}"
+    "issue #{to_reference}"
   end
 
   # Reset issue events cache
diff --git a/app/models/label.rb b/app/models/label.rb
index eee28acefc1..013e6bf5978 100644
--- a/app/models/label.rb
+++ b/app/models/label.rb
@@ -11,6 +11,8 @@
 #
 
 class Label < ActiveRecord::Base
+  include Referable
+
   DEFAULT_COLOR = '#428BCA'
 
   default_value_for :color, DEFAULT_COLOR
@@ -34,6 +36,31 @@ class Label < ActiveRecord::Base
 
   alias_attribute :name, :title
 
+  def self.reference_prefix
+    '~'
+  end
+
+  # Returns the String necessary to reference this Label in Markdown
+  #
+  # format - Symbol format to use (default: :id, optional: :name)
+  #
+  # Note that its argument differs from other objects implementing Referable. If
+  # a non-Symbol argument is given (such as a Project), it will default to :id.
+  #
+  # Examples:
+  #
+  #   Label.first.to_reference        # => "~1"
+  #   Label.first.to_reference(:name) # => "~\"bug\""
+  #
+  # Returns a String
+  def to_reference(format = :id)
+    if format == :name
+      %(#{self.class.reference_prefix}"#{name}")
+    else
+      "#{self.class.reference_prefix}#{id}"
+    end
+  end
+
   def open_issues_count
     issues.opened.count
   end
diff --git a/app/models/merge_request.rb b/app/models/merge_request.rb
index 64f3c39f131..bfbf498591a 100644
--- a/app/models/merge_request.rb
+++ b/app/models/merge_request.rb
@@ -25,10 +25,11 @@ require Rails.root.join("app/models/commit")
 require Rails.root.join("lib/static_model")
 
 class MergeRequest < ActiveRecord::Base
-  include Issuable
-  include Taskable
   include InternalId
+  include Issuable
+  include Referable
   include Sortable
+  include Taskable
 
   belongs_to :target_project, foreign_key: :target_project_id, class_name: "Project"
   belongs_to :source_project, foreign_key: :source_project_id, class_name: "Project"
@@ -135,6 +136,20 @@ class MergeRequest < ActiveRecord::Base
   scope :closed, -> { with_states(:closed, :merged) }
   scope :declined, -> { with_states(:closed) }
 
+  def self.reference_prefix
+    '!'
+  end
+
+  def to_reference(from_project = nil)
+    reference = "#{self.class.reference_prefix}#{iid}"
+
+    if cross_project_reference?(from_project)
+      reference = project.to_reference + reference
+    end
+
+    reference
+  end
+
   def validate_branches
     if target_project == source_project && target_branch == source_branch
       errors.add :branch_conflict, "You can not use same project/branch for source and target"
@@ -291,7 +306,7 @@ class MergeRequest < ActiveRecord::Base
 
   # Mentionable override.
   def gfm_reference
-    "merge request !#{iid}"
+    "merge request #{to_reference}"
   end
 
   def target_project_path
diff --git a/app/models/project.rb b/app/models/project.rb
index 09d3ffd22fe..c943114449a 100644
--- a/app/models/project.rb
+++ b/app/models/project.rb
@@ -33,11 +33,12 @@ require 'carrierwave/orm/activerecord'
 require 'file_size_validator'
 
 class Project < ActiveRecord::Base
-  include Sortable
+  include Gitlab::ConfigHelper
   include Gitlab::ShellAdapter
   include Gitlab::VisibilityLevel
-  include Gitlab::ConfigHelper
   include Rails.application.routes.url_helpers
+  include Referable
+  include Sortable
 
   extend Gitlab::ConfigHelper
   extend Enumerize
@@ -305,6 +306,10 @@ class Project < ActiveRecord::Base
     path
   end
 
+  def to_reference(_from_project = nil)
+    path_with_namespace
+  end
+
   def web_url
     [gitlab_config.url, path_with_namespace].join('/')
   end
diff --git a/app/models/snippet.rb b/app/models/snippet.rb
index d2af26539b6..90fada3c114 100644
--- a/app/models/snippet.rb
+++ b/app/models/snippet.rb
@@ -16,10 +16,11 @@
 #
 
 class Snippet < ActiveRecord::Base
-  include Sortable
-  include Linguist::BlobHelper
   include Gitlab::VisibilityLevel
+  include Linguist::BlobHelper
   include Participable
+  include Referable
+  include Sortable
 
   default_value_for :visibility_level, Snippet::PRIVATE
 
@@ -50,6 +51,20 @@ class Snippet < ActiveRecord::Base
 
   participant :author, :notes
 
+  def self.reference_prefix
+    '$'
+  end
+
+  def to_reference(from_project = nil)
+    reference = "#{self.class.reference_prefix}#{id}"
+
+    if cross_project_reference?(from_project)
+      reference = project.to_reference + reference
+    end
+
+    reference
+  end
+
   def self.content_types
     [
       ".rb", ".py", ".pl", ".scala", ".c", ".cpp", ".java",
diff --git a/app/models/user.rb b/app/models/user.rb
index 4dd37e73564..f546dc015c2 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -62,11 +62,13 @@ require 'carrierwave/orm/activerecord'
 require 'file_size_validator'
 
 class User < ActiveRecord::Base
-  include Sortable
-  include Gitlab::ConfigHelper
-  include TokenAuthenticatable
   extend Gitlab::ConfigHelper
+
+  include Gitlab::ConfigHelper
   include Gitlab::CurrentSettings
+  include Referable
+  include Sortable
+  include TokenAuthenticatable
 
   default_value_for :admin, false
   default_value_for :can_create_group, gitlab_config.default_can_create_group
@@ -247,6 +249,10 @@ class User < ActiveRecord::Base
     def build_user(attrs = {})
       User.new(attrs)
     end
+
+    def reference_prefix
+      '@'
+    end
   end
 
   #
@@ -257,6 +263,10 @@ class User < ActiveRecord::Base
     username
   end
 
+  def to_reference(_from_project = nil)
+    "#{self.class.reference_prefix}#{username}"
+  end
+
   def notification
     @notification ||= Notification.new(self)
   end