21 files changed, 276 insertions, 111 deletions

diff --git a/app/models/blob.rb b/app/models/blob.rb
index 1cdb8811cff..a4fae22a0c4 100644
--- a/app/models/blob.rb
+++ b/app/models/blob.rb
@@ -28,7 +28,7 @@ class Blob < SimpleDelegator
     BlobViewer::Sketch,
 
     BlobViewer::Video,
-    
+
     BlobViewer::PDF,
 
     BlobViewer::BinarySTL,
@@ -75,19 +75,37 @@ class Blob < SimpleDelegator
   end
 
   def no_highlighting?
-    size && size > MAXIMUM_TEXT_HIGHLIGHT_SIZE
+    raw_size && raw_size > MAXIMUM_TEXT_HIGHLIGHT_SIZE
+  end
+
+  def empty?
+    raw_size == 0
   end
 
   def too_large?
     size && truncated?
   end
 
+  def external_storage_error?
+    if external_storage == :lfs
+      !project&.lfs_enabled?
+    else
+      false
+    end
+  end
+
+  def stored_externally?
+    return @stored_externally if defined?(@stored_externally)
+
+    @stored_externally = external_storage && !external_storage_error?
+  end
+
   # Returns the size of the file that this blob represents. If this blob is an
   # LFS pointer, this is the size of the file stored in LFS. Otherwise, this is
   # the size of the blob itself.
   def raw_size
-    if valid_lfs_pointer?
-      lfs_size
+    if stored_externally?
+      external_size
     else
       size
     end
@@ -98,9 +116,13 @@ class Blob < SimpleDelegator
   # text-based rich blob viewer matched on the file's extension. Otherwise, this
   # depends on the type of the blob itself.
   def raw_binary?
-    if valid_lfs_pointer?
+    if stored_externally?
       if rich_viewer
         rich_viewer.binary?
+      elsif Linguist::Language.find_by_filename(name).any?
+        false
+      elsif _mime_type
+        _mime_type.binary?
       else
         true
       end
@@ -118,15 +140,7 @@ class Blob < SimpleDelegator
   end
 
   def readable_text?
-    text? && !valid_lfs_pointer? && !too_large?
-  end
-
-  def valid_lfs_pointer?
-    lfs_pointer? && project&.lfs_enabled?
-  end
-
-  def invalid_lfs_pointer?
-    lfs_pointer? && !project&.lfs_enabled?
+    text? && !stored_externally? && !too_large?
   end
 
   def simple_viewer
@@ -165,10 +179,10 @@ class Blob < SimpleDelegator
   end
 
   def rich_viewer_class
-    return if invalid_lfs_pointer? || empty?
+    return if empty? || external_storage_error?
 
     classes =
-      if valid_lfs_pointer?
+      if stored_externally?
         BINARY_VIEWERS + TEXT_VIEWERS
       elsif binary?
         BINARY_VIEWERS
diff --git a/app/models/blob_viewer/base.rb b/app/models/blob_viewer/base.rb
index f944b00c9d3..a8b91d8d6bc 100644
--- a/app/models/blob_viewer/base.rb
+++ b/app/models/blob_viewer/base.rb
@@ -70,12 +70,13 @@ module BlobViewer
       return @render_error if defined?(@render_error)
 
       @render_error =
-        if server_side_but_stored_in_lfs?
-          # Files stored in LFS can only be rendered using a client-side viewer,
+        if server_side_but_stored_externally?
+          # Files that are not stored in the repository, like LFS files and
+          # build artifacts, can only be rendered using a client-side viewer,
           # since we do not want to read large amounts of data into memory on the
           # server side. Client-side viewers use JS and can fetch the file from
           # `blob_raw_url` using AJAX.
-          :server_side_but_stored_in_lfs
+          :server_side_but_stored_externally
         elsif override_max_size ? absolutely_too_large? : too_large?
           :too_large
         end
@@ -89,8 +90,8 @@ module BlobViewer
 
     private
 
-    def server_side_but_stored_in_lfs?
-      server_side? && blob.valid_lfs_pointer?
+    def server_side_but_stored_externally?
+      server_side? && blob.stored_externally?
     end
   end
 end
diff --git a/app/models/ci/artifact_blob.rb b/app/models/ci/artifact_blob.rb
new file mode 100644
index 00000000000..b35febc9ac5
--- /dev/null
+++ b/app/models/ci/artifact_blob.rb
@@ -0,0 +1,35 @@
+module Ci
+  class ArtifactBlob
+    include BlobLike
+
+    attr_reader :entry
+
+    def initialize(entry)
+      @entry = entry
+    end
+
+    delegate :name, :path, to: :entry
+
+    def id
+      Digest::SHA1.hexdigest(path)
+    end
+
+    def size
+      entry.metadata[:size]
+    end
+
+    def data
+      "Build artifact #{path}"
+    end
+
+    def mode
+      entry.metadata[:mode]
+    end
+
+    def external_storage
+      :build_artifact
+    end
+
+    alias_method :external_size, :size
+  end
+end
diff --git a/app/models/commit.rb b/app/models/commit.rb
index bb4cb8efd15..88a015cdb77 100644
--- a/app/models/commit.rb
+++ b/app/models/commit.rb
@@ -236,8 +236,8 @@ class Commit
     project.pipelines.where(sha: sha)
   end
 
-  def latest_pipeline
-    pipelines.last
+  def last_pipeline
+    @last_pipeline ||= pipelines.last
   end
 
   def status(ref = nil)
diff --git a/app/models/concerns/blob_like.rb b/app/models/concerns/blob_like.rb
new file mode 100644
index 00000000000..adb81561000
--- /dev/null
+++ b/app/models/concerns/blob_like.rb
@@ -0,0 +1,48 @@
+module BlobLike
+  extend ActiveSupport::Concern
+  include Linguist::BlobHelper
+
+  def id
+    raise NotImplementedError
+  end
+
+  def name
+    raise NotImplementedError
+  end
+
+  def path
+    raise NotImplementedError
+  end
+
+  def size
+    0
+  end
+
+  def data
+    nil
+  end
+
+  def mode
+    nil
+  end
+
+  def binary?
+    false
+  end
+
+  def load_all_data!(repository)
+    # No-op
+  end
+
+  def truncated?
+    false
+  end
+
+  def external_storage
+    nil
+  end
+
+  def external_size
+    nil
+  end
+end
diff --git a/app/models/concerns/cache_markdown_field.rb b/app/models/concerns/cache_markdown_field.rb
index f033028c4e5..eb32bf3d32a 100644
--- a/app/models/concerns/cache_markdown_field.rb
+++ b/app/models/concerns/cache_markdown_field.rb
@@ -78,6 +78,9 @@ module CacheMarkdownField
   def cached_html_up_to_date?(markdown_field)
     html_field = cached_markdown_fields.html_field(markdown_field)
 
+    cached = !cached_html_for(markdown_field).nil? && !__send__(markdown_field).nil?
+    return false unless cached
+
     markdown_changed = attribute_changed?(markdown_field) || false
     html_changed = attribute_changed?(html_field) || false
 
diff --git a/app/models/concerns/discussion_on_diff.rb b/app/models/concerns/discussion_on_diff.rb
index 8ee42875670..a7bdf5587b2 100644
--- a/app/models/concerns/discussion_on_diff.rb
+++ b/app/models/concerns/discussion_on_diff.rb
@@ -11,6 +11,7 @@ module DiscussionOnDiff
               :diff_line,
               :for_line?,
               :active?,
+              :created_at_diff?,
 
               to: :first_note
 
diff --git a/app/models/concerns/note_on_diff.rb b/app/models/concerns/note_on_diff.rb
index 6c27dd5aa5c..6359f7596b1 100644
--- a/app/models/concerns/note_on_diff.rb
+++ b/app/models/concerns/note_on_diff.rb
@@ -30,6 +30,10 @@ module NoteOnDiff
     raise NotImplementedError
   end
 
+  def created_at_diff?(diff_refs)
+    false
+  end
+
   private
 
   def noteable_diff_refs
diff --git a/app/models/diff_discussion.rb b/app/models/diff_discussion.rb
index 6a6466b493b..d627fbe327f 100644
--- a/app/models/diff_discussion.rb
+++ b/app/models/diff_discussion.rb
@@ -10,7 +10,6 @@ class DiffDiscussion < Discussion
 
   delegate  :position,
             :original_position,
-            :latest_merge_request_diff,
 
             to: :first_note
 
@@ -18,6 +17,25 @@ class DiffDiscussion < Discussion
     false
   end
 
+  def merge_request_version_params
+    return unless for_merge_request?
+
+    if active?
+      {}
+    else
+      diff_refs = position.diff_refs
+
+      if diff = noteable.merge_request_diff_for(diff_refs)
+        { diff_id: diff.id }
+      elsif diff = noteable.merge_request_diff_for(diff_refs.head_sha)
+        {
+          diff_id: diff.id,
+          start_sha: diff_refs.start_sha
+        }
+      end
+    end
+  end
+
   def reply_attributes
     super.merge(
       original_position: original_position.to_json,
diff --git a/app/models/diff_note.rb b/app/models/diff_note.rb
index abe4518d62a..76c59199afd 100644
--- a/app/models/diff_note.rb
+++ b/app/models/diff_note.rb
@@ -65,10 +65,11 @@ class DiffNote < Note
     self.position.diff_refs == diff_refs
   end
 
-  def latest_merge_request_diff
-    return unless for_merge_request?
+  def created_at_diff?(diff_refs)
+    return false unless supported?
+    return true if for_commit?
 
-    self.noteable.merge_request_diff_for(self.position.diff_refs)
+    self.original_position.diff_refs == diff_refs
   end
 
   private
diff --git a/app/models/issue.rb b/app/models/issue.rb
index 305fc01f041..78bde6820da 100644
--- a/app/models/issue.rb
+++ b/app/models/issue.rb
@@ -143,6 +143,14 @@ class Issue < ActiveRecord::Base
     branches_with_iid - branches_with_merge_request
   end
 
+  # Returns boolean if a related branch exists for the current issue
+  # ignores merge requests branchs
+  def has_related_branch? 
+    project.repository.branch_names.any? do |branch|
+      /\A#{iid}-(?!\d+-stable)/i =~ branch
+    end
+  end
+
   # To allow polymorphism with MergeRequest.
   def source_project
     project
diff --git a/app/models/legacy_diff_discussion.rb b/app/models/legacy_diff_discussion.rb
index e617ce36f56..3c1d34db5fa 100644
--- a/app/models/legacy_diff_discussion.rb
+++ b/app/models/legacy_diff_discussion.rb
@@ -9,14 +9,14 @@ class LegacyDiffDiscussion < Discussion
 
   memoized_values << :active
 
-  def legacy_diff_discussion?
-    true
-  end
-
   def self.note_class
     LegacyDiffNote
   end
 
+  def legacy_diff_discussion?
+    true
+  end
+
   def active?(*args)
     return @active if @active.present?
 
@@ -27,6 +27,16 @@ class LegacyDiffDiscussion < Discussion
     !active?
   end
 
+  def merge_request_version_params
+    return unless for_merge_request?
+
+    if active?
+      {}
+    else
+      nil
+    end
+  end
+
   def reply_attributes
     super.merge(line_code: line_code)
   end
diff --git a/app/models/merge_request.rb b/app/models/merge_request.rb
index 9d2288c311e..12c5481cd6d 100644
--- a/app/models/merge_request.rb
+++ b/app/models/merge_request.rb
@@ -100,6 +100,7 @@ class MergeRequest < ActiveRecord::Base
   validates :merge_user, presence: true, if: :merge_when_pipeline_succeeds?, unless: :importing?
   validate :validate_branches, unless: [:allow_broken, :importing?, :closed_without_fork?]
   validate :validate_fork, unless: :closed_without_fork?
+  validate :validate_target_project, on: :create
 
   scope :by_source_or_target_branch, ->(branch_name) do
     where("source_branch = :branch OR target_branch = :branch", branch: branch_name)
@@ -330,6 +331,12 @@ class MergeRequest < ActiveRecord::Base
     end
   end
 
+  def validate_target_project
+    return true if target_project.merge_requests_enabled?
+
+    errors.add :base, 'Target project has disabled merge requests'
+  end
+
   def validate_fork
     return true unless target_project && source_project
     return true if target_project == source_project
@@ -367,12 +374,18 @@ class MergeRequest < ActiveRecord::Base
     merge_request_diff(true)
   end
 
-  def merge_request_diff_for(diff_refs)
-    @merge_request_diffs_by_diff_refs ||= Hash.new do |h, diff_refs|
-      h[diff_refs] = merge_request_diffs.viewable.select_without_diff.find_by_diff_refs(diff_refs)
+  def merge_request_diff_for(diff_refs_or_sha)
+    @merge_request_diffs_by_diff_refs_or_sha ||= Hash.new do |h, diff_refs_or_sha|
+      diffs = merge_request_diffs.viewable.select_without_diff
+      h[diff_refs_or_sha] =
+        if diff_refs_or_sha.is_a?(Gitlab::Diff::DiffRefs)
+          diffs.find_by_diff_refs(diff_refs_or_sha)
+        else
+          diffs.find_by(head_commit_sha: diff_refs_or_sha)
+        end
     end
 
-    @merge_request_diffs_by_diff_refs[diff_refs]
+    @merge_request_diffs_by_diff_refs_or_sha[diff_refs_or_sha]
   end
 
   def reload_diff_if_branch_changed
diff --git a/app/models/namespace.rb b/app/models/namespace.rb
index 9bfa731785f..397dc7a25ab 100644
--- a/app/models/namespace.rb
+++ b/app/models/namespace.rb
@@ -33,7 +33,7 @@ class Namespace < ActiveRecord::Base
   validates :path,
     presence: true,
     length: { maximum: 255 },
-    namespace: true
+    dynamic_path: true
 
   validate :nesting_level_allowed
 
@@ -220,6 +220,10 @@ class Namespace < ActiveRecord::Base
     Project.inside_path(full_path)
   end
 
+  def has_parent?
+    parent.present?
+  end
+
   private
 
   def repository_storage_paths
diff --git a/app/models/note.rb b/app/models/note.rb
index e720bfba030..b06985b4a6f 100644
--- a/app/models/note.rb
+++ b/app/models/note.rb
@@ -115,11 +115,19 @@ class Note < ActiveRecord::Base
     end
 
     def grouped_diff_discussions(diff_refs = nil)
-      diff_notes.
-        fresh.
-        discussions.
-        select { |n| n.active?(diff_refs) }.
-        group_by(&:line_code)
+      groups = {}
+
+      diff_notes.fresh.discussions.each do |discussion|
+        if discussion.active?(diff_refs)
+          discussions = groups[discussion.line_code] ||= []
+        elsif diff_refs && discussion.created_at_diff?(diff_refs)
+          discussions = groups[discussion.original_line_code] ||= []
+        end
+
+        discussions << discussion if discussions
+      end
+
+      groups
     end
 
     def count_for_collection(ids, type)
@@ -141,10 +149,6 @@ class Note < ActiveRecord::Base
     true
   end
 
-  def latest_merge_request_diff
-    nil
-  end
-
   def max_attachment_size
     current_application_settings.max_attachment_size.megabytes.to_i
   end
diff --git a/app/models/project.rb b/app/models/project.rb
index c7dc562c238..025db89ebfd 100644
--- a/app/models/project.rb
+++ b/app/models/project.rb
@@ -196,13 +196,14 @@ class Project < ActiveRecord::Base
               message: Gitlab::Regex.project_name_regex_message }
   validates :path,
     presence: true,
-    project_path: true,
+    dynamic_path: true,
     length: { maximum: 255 },
     format: { with: Gitlab::Regex.project_path_regex,
-              message: Gitlab::Regex.project_path_regex_message }
+              message: Gitlab::Regex.project_path_regex_message },
+    uniqueness: { scope: :namespace_id }
+
   validates :namespace, presence: true
   validates :name, uniqueness: { scope: :namespace_id }
-  validates :path, uniqueness: { scope: :namespace_id }
   validates :import_url, addressable_url: true, if: :external_import?
   validates :import_url, importable_url: true, if: [:external_import?, :import_url_changed?]
   validates :star_count, numericality: { greater_than_or_equal_to: 0 }
@@ -1270,6 +1271,9 @@ class Project < ActiveRecord::Base
     else
       update_attribute(name, value)
     end
+
+  rescue ActiveRecord::RecordNotSaved => e
+    handle_update_attribute_error(e, value)
   end
 
   def pushes_since_gc
@@ -1314,6 +1318,14 @@ class Project < ActiveRecord::Base
     namespace_id_changed?
   end
 
+  def default_merge_request_target
+    if forked_from_project&.merge_requests_enabled?
+      forked_from_project
+    else
+      self
+    end
+  end
+
   alias_method :name_with_namespace, :full_name
   alias_method :human_name, :full_name
   alias_method :path_with_namespace, :full_path
@@ -1383,4 +1395,16 @@ class Project < ActiveRecord::Base
 
     ContainerRepository.build_root_repository(self).has_tags?
   end
+
+  def handle_update_attribute_error(ex, value)
+    if ex.message.start_with?('Failed to replace')
+      if value.respond_to?(:each)
+        invalid = value.detect(&:invalid?)
+
+        raise ex, ([ex.message] + invalid.errors.full_messages).join(' ') if invalid
+      end
+    end
+
+    raise ex
+  end
 end
diff --git a/app/models/project_services/chat_message/base_message.rb b/app/models/project_services/chat_message/base_message.rb
index 7621a5fa2d8..e2ad586aea7 100644
--- a/app/models/project_services/chat_message/base_message.rb
+++ b/app/models/project_services/chat_message/base_message.rb
@@ -50,5 +50,16 @@ module ChatMessage
     def link(text, url)
       "[#{text}](#{url})"
     end
+
+    def pretty_duration(seconds)
+      parse_string =
+        if duration < 1.hour
+          '%M:%S'
+        else
+          '%H:%M:%S'
+        end
+
+      Time.at(seconds).utc.strftime(parse_string)
+    end
   end
 end
diff --git a/app/models/project_services/chat_message/pipeline_message.rb b/app/models/project_services/chat_message/pipeline_message.rb
index 4628d9b1a7b..47b68f00cff 100644
--- a/app/models/project_services/chat_message/pipeline_message.rb
+++ b/app/models/project_services/chat_message/pipeline_message.rb
@@ -15,7 +15,7 @@ module ChatMessage
       @ref_type = pipeline_attributes[:tag] ? 'tag' : 'branch'
       @ref = pipeline_attributes[:ref]
       @status = pipeline_attributes[:status]
-      @duration = pipeline_attributes[:duration]
+      @duration = pipeline_attributes[:duration].to_i
       @pipeline_id = pipeline_attributes[:id]
     end
 
@@ -37,7 +37,7 @@ module ChatMessage
       {
         title: "Pipeline #{pipeline_link} of #{branch_link} #{ref_type} by #{user_name} #{humanized_status}",
         subtitle: "in #{project_link}",
-        text: "in #{duration} #{time_measure}",
+        text: "in #{pretty_duration(duration)}",
         image: user_avatar || ''
       }
     end
@@ -45,7 +45,7 @@ module ChatMessage
     private
 
     def message
-      "#{project_link}: Pipeline #{pipeline_link} of #{branch_link} #{ref_type} by #{user_name} #{humanized_status} in #{duration} #{time_measure}"
+      "#{project_link}: Pipeline #{pipeline_link} of #{branch_link} #{ref_type} by #{user_name} #{humanized_status} in #{pretty_duration(duration)}"
     end
 
     def humanized_status
@@ -84,9 +84,5 @@ module ChatMessage
     def pipeline_link
       "[##{pipeline_id}](#{pipeline_url})"
     end
-
-    def time_measure
-      'second'.pluralize(duration)
-    end
   end
 end
diff --git a/app/models/repository.rb b/app/models/repository.rb
index feabfa111fb..0c797dd5814 100644
--- a/app/models/repository.rb
+++ b/app/models/repository.rb
@@ -505,14 +505,8 @@ class Repository
   delegate :tag_names, to: :raw_repository
   cache_method :tag_names, fallback: []
 
-  def branch_count
-    branches.size
-  end
+  delegate :branch_count, :tag_count, to: :raw_repository
   cache_method :branch_count, fallback: 0
-
-  def tag_count
-    raw_repository.rugged.tags.count
-  end
   cache_method :tag_count, fallback: 0
 
   def avatar
@@ -795,7 +789,7 @@ class Repository
       }
       options.merge!(get_committer_and_author(user, email: author_email, name: author_name))
 
-      Rugged::Commit.create(rugged, options)
+      create_commit(options)
     end
   end
   # rubocop:enable Metrics/ParameterLists
@@ -842,7 +836,7 @@ class Repository
         tree: merge_index.write_tree(rugged),
       )
 
-      commit_id = Rugged::Commit.create(rugged, actual_options)
+      commit_id = create_commit(actual_options)
       merge_request.update(in_progress_merge_commit_sha: commit_id)
       commit_id
     end
@@ -865,12 +859,11 @@ class Repository
 
       committer = user_to_committer(user)
 
-      Rugged::Commit.create(rugged,
-        message: commit.revert_message(user),
-        author: committer,
-        committer: committer,
-        tree: revert_tree_id,
-        parents: [start_commit.sha])
+      create_commit(message: commit.revert_message(user),
+                    author: committer,
+                    committer: committer,
+                    tree: revert_tree_id,
+                    parents: [start_commit.sha])
     end
   end
 
@@ -889,16 +882,15 @@ class Repository
 
       committer = user_to_committer(user)
 
-      Rugged::Commit.create(rugged,
-        message: commit.message,
-        author: {
-          email: commit.author_email,
-          name: commit.author_name,
-          time: commit.authored_date
-        },
-        committer: committer,
-        tree: cherry_pick_tree_id,
-        parents: [start_commit.sha])
+      create_commit(message: commit.message,
+                    author: {
+                        email: commit.author_email,
+                        name: commit.author_name,
+                        time: commit.authored_date
+                    },
+                    committer: committer,
+                    tree: cherry_pick_tree_id,
+                    parents: [start_commit.sha])
     end
   end
 
@@ -906,7 +898,7 @@ class Repository
     GitOperationService.new(user, self).with_branch(branch_name) do
       committer = user_to_committer(user)
 
-      Rugged::Commit.create(rugged, params.merge(author: committer, committer: committer))
+      create_commit(params.merge(author: committer, committer: committer))
     end
   end
 
@@ -1148,6 +1140,12 @@ class Repository
     Gitlab::Metrics.add_event(event, { path: path_with_namespace }.merge(tags))
   end
 
+  def create_commit(params = {})
+    params[:message].delete!("\r")
+
+    Rugged::Commit.create(rugged, params)
+  end
+
   def repository_storage_path
     @project.repository_storage_path
   end
diff --git a/app/models/snippet_blob.rb b/app/models/snippet_blob.rb
index d6cab74eb1a..fa5fa151607 100644
--- a/app/models/snippet_blob.rb
+++ b/app/models/snippet_blob.rb
@@ -1,5 +1,5 @@
 class SnippetBlob
-  include Linguist::BlobHelper
+  include BlobLike
 
   attr_reader :snippet
 
@@ -28,32 +28,4 @@ class SnippetBlob
 
     Banzai.render_field(snippet, :content)
   end
-
-  def mode
-    nil
-  end
-
-  def binary?
-    false
-  end
-
-  def load_all_data!(repository)
-    # No-op
-  end
-
-  def lfs_pointer?
-    false
-  end
-
-  def lfs_oid
-    nil
-  end
-
-  def lfs_size
-    nil
-  end
-
-  def truncated?
-    false
-  end
 end
diff --git a/app/models/user.rb b/app/models/user.rb
index bd9c9f99663..2b7ebe6c1a7 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -118,7 +118,7 @@ class User < ActiveRecord::Base
     presence: true,
     numericality: { greater_than_or_equal_to: 0, less_than_or_equal_to: Gitlab::Database::MAX_INT_VALUE }
   validates :username,
-    namespace: true,
+    dynamic_path: true,
     presence: true,
     uniqueness: { case_sensitive: false }