Merge branch 'bvl-patches-via-mail' into 'master'

Allow to add patches to merge requests created via email

Closes #40830

See merge request gitlab-org/gitlab-ce!22723

31 files changed, 1065 insertions, 13 deletions

diff --git a/app/services/commits/commit_patch_service.rb b/app/services/commits/commit_patch_service.rb
new file mode 100644
index 00000000000..9253cfaac20
--- /dev/null
+++ b/app/services/commits/commit_patch_service.rb
@@ -0,0 +1,61 @@
+# frozen_string_literal: true
+
+module Commits
+  class CommitPatchService < CreateService
+    # Requires:
+    # - project: `Project` to be committed into
+    # - user: `User` that will be the committer
+    # - params:
+    #   - branch_name: `String` the branch that will be committed into
+    #   - start_branch: `String` the branch that will will started from
+    #   - patches: `Gitlab::Git::Patches::Collection` that contains the patches
+    def initialize(*args)
+      super
+
+      @patches = Gitlab::Git::Patches::Collection.new(Array(params[:patches]))
+    end
+
+    private
+
+    def new_branch?
+      !repository.branch_exists?(@branch_name)
+    end
+
+    def create_commit!
+      if @start_branch && new_branch?
+        prepare_branch!
+      end
+
+      Gitlab::Git::Patches::CommitPatches
+        .new(current_user, project.repository, @branch_name, @patches)
+        .commit
+    end
+
+    def prepare_branch!
+      branch_result = CreateBranchService.new(project, current_user)
+                        .execute(@branch_name, @start_branch)
+
+      if branch_result[:status] != :success
+        raise ChangeError, branch_result[:message]
+      end
+    end
+
+    # Overridden from the Commits::CreateService, to skip some validations we
+    # don't need:
+    # - validate_on_branch!
+    #   Not needed, the patches are applied on top of HEAD if the branch did not
+    #   exist
+    # - validate_branch_existence!
+    #   Not needed because we continue applying patches on the branch if it
+    #   already existed, and create it if it did not exist.
+    def validate!
+      validate_patches!
+      validate_new_branch_name! if new_branch?
+      validate_permissions!
+    end
+
+    def validate_patches!
+      raise_error("Patches are too big") unless @patches.valid_size?
+    end
+  end
+end
diff --git a/app/services/commits/create_service.rb b/app/services/commits/create_service.rb
index 3ce9acc833c..34593e12bd5 100644
--- a/app/services/commits/create_service.rb
+++ b/app/services/commits/create_service.rb
@@ -19,7 +19,12 @@ module Commits
       new_commit = create_commit!
 
       success(result: new_commit)
-    rescue ValidationError, ChangeError, Gitlab::Git::Index::IndexError, Gitlab::Git::CommitError, Gitlab::Git::PreReceiveError => ex
+    rescue ValidationError,
+           ChangeError,
+           Gitlab::Git::Index::IndexError,
+           Gitlab::Git::CommitError,
+           Gitlab::Git::PreReceiveError,
+           Gitlab::Git::CommandError => ex
       error(ex.message)
     end
 
diff --git a/app/services/issuable_base_service.rb b/app/services/issuable_base_service.rb
index c388913ae65..e32e262ac31 100644
--- a/app/services/issuable_base_service.rb
+++ b/app/services/issuable_base_service.rb
@@ -126,12 +126,12 @@ class IssuableBaseService < BaseService
     merge_quick_actions_into_params!(issuable)
   end
 
-  def merge_quick_actions_into_params!(issuable)
+  def merge_quick_actions_into_params!(issuable, only: nil)
     original_description = params.fetch(:description, issuable.description)
 
     description, command_params =
       QuickActions::InterpretService.new(project, current_user)
-        .execute(original_description, issuable)
+        .execute(original_description, issuable, only: only)
 
     # Avoid a description already set on an issuable to be overwritten by a nil
     params[:description] = description if description
diff --git a/app/services/merge_requests/build_service.rb b/app/services/merge_requests/build_service.rb
index 0e76d2cc3ab..6c69452e2ab 100644
--- a/app/services/merge_requests/build_service.rb
+++ b/app/services/merge_requests/build_service.rb
@@ -6,8 +6,12 @@ module MergeRequests
 
     def execute
       @params_issue_iid = params.delete(:issue_iid)
+      self.merge_request = MergeRequest.new
+      # TODO: this should handle all quick actions that don't have side effects
+      # https://gitlab.com/gitlab-org/gitlab-ce/issues/53658
+      merge_quick_actions_into_params!(merge_request, only: [:target_branch])
+      merge_request.assign_attributes(params)
 
-      self.merge_request = MergeRequest.new(params)
       merge_request.author = current_user
       merge_request.compare_commits = []
       merge_request.source_project  = find_source_project
diff --git a/app/services/quick_actions/interpret_service.rb b/app/services/quick_actions/interpret_service.rb
index eb431c36807..9c81de7e90e 100644
--- a/app/services/quick_actions/interpret_service.rb
+++ b/app/services/quick_actions/interpret_service.rb
@@ -23,13 +23,13 @@ module QuickActions
 
     # Takes a text and interprets the commands that are extracted from it.
     # Returns the content without commands, and hash of changes to be applied to a record.
-    def execute(content, issuable)
+    def execute(content, issuable, only: nil)
       return [content, {}] unless current_user.can?(:use_quick_actions)
 
       @issuable = issuable
       @updates = {}
 
-      content, commands = extractor.extract_commands(content)
+      content, commands = extractor.extract_commands(content, only: only)
       extract_updates(commands)
 
       [content, @updates]
diff --git a/app/workers/email_receiver_worker.rb b/app/workers/email_receiver_worker.rb
index 12706613ac2..bf637f82df2 100644
--- a/app/workers/email_receiver_worker.rb
+++ b/app/workers/email_receiver_worker.rb
@@ -40,6 +40,8 @@ class EmailReceiverWorker
         "You are not allowed to perform this action. If you believe this is in error, contact a staff member."
       when Gitlab::Email::NoteableNotFoundError
         "The thread you are replying to no longer exists, perhaps it was deleted? If you believe this is in error, contact a staff member."
+      when Gitlab::Email::InvalidAttachment
+        error.message
       when Gitlab::Email::InvalidRecordError
         can_retry = true
         error.message
diff --git a/changelogs/unreleased/bvl-patches-via-mail.yml b/changelogs/unreleased/bvl-patches-via-mail.yml
new file mode 100644
index 00000000000..6fd9e6a956c
--- /dev/null
+++ b/changelogs/unreleased/bvl-patches-via-mail.yml
@@ -0,0 +1,5 @@
+---
+title: Allow adding patches when creating a merge request via email
+merge_request: 22723
+author: Serdar Dogruyol
+type: added
diff --git a/doc/user/project/merge_requests/index.md b/doc/user/project/merge_requests/index.md
index 0a7f7d37384..6de2ab07fc4 100644
--- a/doc/user/project/merge_requests/index.md
+++ b/doc/user/project/merge_requests/index.md
@@ -166,6 +166,23 @@ administrator to do so.
 
 ![Create new merge requests by email](img/create_from_email.png)
 
+### Adding patches when creating a merge request via e-mail
+
+> **Note**: This feature was [implemented in GitLab 11.5](https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/22723)
+
+You can add commits to the merge request being created by adding
+patches as attachments to the email, all attachments with a filename
+ending in `.patch` will be considered patches. The patches will be processed
+ordered by name.
+
+The combined size of the patches can be 2MB.
+
+If the source branch from the subject does not exist, it will be
+created from the repository's HEAD or the specified target branch to
+apply the patches. The target branch can be specified using the
+[`/target_branch` quick action](../quick_actions.md). If the source
+branch already exists, the patches will be applied on top of it.
+
 ## Find the merge request that introduced a change
 
 > **Note**: this feature was [implemented in GitLab 10.5](https://gitlab.com/gitlab-org/gitlab-ce/issues/2383).
diff --git a/lib/gitlab/email/handler/create_merge_request_handler.rb b/lib/gitlab/email/handler/create_merge_request_handler.rb
index e68ae60ff98..5772727e855 100644
--- a/lib/gitlab/email/handler/create_merge_request_handler.rb
+++ b/lib/gitlab/email/handler/create_merge_request_handler.rb
@@ -44,10 +44,26 @@ module Gitlab
           @project ||= Project.find_by_full_path(project_path)
         end
 
+        def metrics_params
+          super.merge(includes_patches: patch_attachments.any?)
+        end
+
         private
 
+        def build_merge_request
+          MergeRequests::BuildService.new(project, author, merge_request_params).execute
+        end
+
         def create_merge_request
-          merge_request = MergeRequests::BuildService.new(project, author, merge_request_params).execute
+          merge_request = build_merge_request
+
+          if patch_attachments.any?
+            apply_patches_to_source_branch(start_branch: merge_request.target_branch)
+            remove_patch_attachments
+            # Rebuild the merge request as the source branch might just have
+            # been created, so we should re-validate.
+            merge_request = build_merge_request
+          end
 
           if merge_request.errors.any?
             merge_request
@@ -59,12 +75,42 @@ module Gitlab
         def merge_request_params
           params = {
             source_project_id: project.id,
-            source_branch: mail.subject,
+            source_branch: source_branch,
             target_project_id: project.id
           }
           params[:description] = message if message.present?
           params
         end
+
+        def apply_patches_to_source_branch(start_branch:)
+          patches = patch_attachments.map { |patch| patch.body.decoded }
+
+          result = Commits::CommitPatchService
+                     .new(project, author, branch_name: source_branch, patches: patches, start_branch: start_branch)
+                     .execute
+
+          if result[:status] != :success
+            message = "Could not apply patches to #{source_branch}:\n#{result[:message]}"
+            raise InvalidAttachment, message
+          end
+        end
+
+        def remove_patch_attachments
+          patch_attachments.each { |patch| mail.parts.delete(patch) }
+          # reset the message, so it needs to be reporocessed when the attachments
+          # have been modified
+          @message = nil
+        end
+
+        def patch_attachments
+          @patches ||= mail.attachments
+                         .select { |attachment| attachment.filename.ends_with?('.patch') }
+                         .sort_by(&:filename)
+        end
+
+        def source_branch
+          @source_branch ||= mail.subject
+        end
       end
     end
   end
diff --git a/lib/gitlab/email/receiver.rb b/lib/gitlab/email/receiver.rb
index d8c594ad0e7..3a689967a64 100644
--- a/lib/gitlab/email/receiver.rb
+++ b/lib/gitlab/email/receiver.rb
@@ -18,6 +18,7 @@ module Gitlab
     InvalidIssueError = Class.new(InvalidRecordError)
     InvalidMergeRequestError = Class.new(InvalidRecordError)
     UnknownIncomingEmail = Class.new(ProcessingError)
+    InvalidAttachment = Class.new(ProcessingError)
 
     class Receiver
       def initialize(raw)
diff --git a/lib/gitlab/git/patches/collection.rb b/lib/gitlab/git/patches/collection.rb
new file mode 100644
index 00000000000..ad6b5d32abc
--- /dev/null
+++ b/lib/gitlab/git/patches/collection.rb
@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module Git
+    module Patches
+      class Collection
+        MAX_PATCH_SIZE = 2.megabytes
+
+        def initialize(one_or_more_patches)
+          @patches = Array(one_or_more_patches).map do |patch_content|
+            Gitlab::Git::Patches::Patch.new(patch_content)
+          end
+        end
+
+        def content
+          @patches.map(&:content).join("\n")
+        end
+
+        def valid_size?
+          size < MAX_PATCH_SIZE
+        end
+
+        # rubocop: disable CodeReuse/ActiveRecord
+        # `@patches` is not an `ActiveRecord` relation, but an `Enumerable`
+        # We're using sum from `ActiveSupport`
+        def size
+          @size ||= @patches.sum(&:size)
+        end
+        # rubocop: enable CodeReuse/ActiveRecord
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/git/patches/commit_patches.rb b/lib/gitlab/git/patches/commit_patches.rb
new file mode 100644
index 00000000000..c62994432d3
--- /dev/null
+++ b/lib/gitlab/git/patches/commit_patches.rb
@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module Git
+    module Patches
+      class CommitPatches
+        include Gitlab::Git::WrapsGitalyErrors
+
+        def initialize(user, repository, branch, patch_collection)
+          @user, @repository, @branch, @patches = user, repository, branch, patch_collection
+        end
+
+        def commit
+          repository.with_cache_hooks do
+            wrapped_gitaly_errors do
+              operation_service.user_commit_patches(user, branch, patches.content)
+            end
+          end
+        end
+
+        private
+
+        attr_reader :user, :repository, :branch, :patches
+
+        def operation_service
+          repository.raw.gitaly_operation_client
+        end
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/git/patches/patch.rb b/lib/gitlab/git/patches/patch.rb
new file mode 100644
index 00000000000..fe6ae1b5b00
--- /dev/null
+++ b/lib/gitlab/git/patches/patch.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module Git
+    module Patches
+      class Patch
+        attr_reader :content
+
+        def initialize(content)
+          @content = content
+        end
+
+        def size
+          content.bytesize
+        end
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/gitaly_client/operation_service.rb b/lib/gitlab/gitaly_client/operation_service.rb
index 1f42f657f68..4c78b790ce5 100644
--- a/lib/gitlab/gitaly_client/operation_service.rb
+++ b/lib/gitlab/gitaly_client/operation_service.rb
@@ -299,6 +299,29 @@ module Gitlab
         Gitlab::Git::OperationService::BranchUpdate.from_gitaly(response.branch_update)
       end
 
+      def user_commit_patches(user, branch_name, patches)
+        header = Gitaly::UserApplyPatchRequest::Header.new(
+          repository: @gitaly_repo,
+          user: Gitlab::Git::User.from_gitlab(user).to_gitaly,
+          target_branch: encode_binary(branch_name)
+        )
+        reader = binary_stringio(patches)
+
+        chunks = Enumerator.new do |chunk|
+          chunk.yield Gitaly::UserApplyPatchRequest.new(header: header)
+
+          until reader.eof?
+            patch_chunk = reader.read(MAX_MSG_SIZE)
+
+            chunk.yield(Gitaly::UserApplyPatchRequest.new(patches: patch_chunk))
+          end
+        end
+
+        response = GitalyClient.call(@repository.storage, :operation_service, :user_apply_patch, chunks)
+
+        Gitlab::Git::OperationService::BranchUpdate.from_gitaly(response.branch_update)
+      end
+
       private
 
       def call_cherry_pick_or_revert(rpc, user:, commit:, branch_name:, message:, start_branch_name:, start_repository:)
diff --git a/lib/gitlab/quick_actions/extractor.rb b/lib/gitlab/quick_actions/extractor.rb
index 30c6806b68e..59f8dd889aa 100644
--- a/lib/gitlab/quick_actions/extractor.rb
+++ b/lib/gitlab/quick_actions/extractor.rb
@@ -29,7 +29,7 @@ module Gitlab
       # commands = extractor.extract_commands(msg) #=> [['labels', '~foo ~"bar baz"']]
       # msg #=> "hello\nworld"
       # ```
-      def extract_commands(content)
+      def extract_commands(content, only: nil)
         return [content, []] unless content
 
         content = content.dup
@@ -37,7 +37,7 @@ module Gitlab
         commands = []
 
         content.delete!("\r")
-        content.gsub!(commands_regex) do
+        content.gsub!(commands_regex(only: only)) do
           if $~[:cmd]
             commands << [$~[:cmd].downcase, $~[:arg]].reject(&:blank?)
             ''
@@ -60,8 +60,8 @@ module Gitlab
       # It looks something like:
       #
       #   /^\/(?<cmd>close|reopen|...)(?:( |$))(?<arg>[^\/\n]*)(?:\n|$)/
-      def commands_regex
-        names = command_names.map(&:to_s)
+      def commands_regex(only:)
+        names = command_names(limit_to_commands: only).map(&:to_s)
 
         @commands_regex ||= %r{
             (?<code>
@@ -133,10 +133,14 @@ module Gitlab
         [content, commands]
       end
 
-      def command_names
+      def command_names(limit_to_commands:)
         command_definitions.flat_map do |command|
           next if command.noop?
 
+          if limit_to_commands && (command.all_names & limit_to_commands).empty?
+            next
+          end
+
           command.all_names
         end.compact
       end
diff --git a/spec/fixtures/emails/merge_request_multiple_patches.eml b/spec/fixtures/emails/merge_request_multiple_patches.eml
new file mode 100644
index 00000000000..311b99a525d
--- /dev/null
+++ b/spec/fixtures/emails/merge_request_multiple_patches.eml
@@ -0,0 +1,181 @@
+From: "Jake the Dog" <jake@adventuretime.ooo>
+To: incoming+gitlabhq/gitlabhq+merge-request+auth_token@appmail.adventuretime.ooo
+Subject: new-branch-with-a-patch
+Date: Wed, 31 Oct 2018 17:27:52 +0100
+X-Mailer: MailMate (1.12r5523)
+Message-ID: <7BE7C2E6-F0D9-4C85-9F55-B2A4BA01BFEC@gitlab.com>
+MIME-Version: 1.0
+Content-Type: multipart/mixed;
+ boundary="=_MailMate_D2C4B06A-4F8D-4AAB-B247-C507E35AAED6_="
+
+
+--=_MailMate_D2C4B06A-4F8D-4AAB-B247-C507E35AAED6_=
+
+This applies nicely to a branch freshly created from the root-ref
+
+The other attachments in this email are ignored
+
+--=_MailMate_D2C4B06A-4F8D-4AAB-B247-C507E35AAED6_=
+Content-Disposition: attachment;
+ filename=0002-This-does-not-apply-to-the-feature-branch.patch
+Content-Transfer-Encoding: quoted-printable
+
+=46rom 00c68c2b4f954370ce82a1162bc29c13f524897e Mon Sep 17 00:00:00 2001
+From: Patch user <patchuser@gitlab.org>
+Date: Mon, 22 Oct 2018 11:05:48 +0200
+Subject: [PATCH] This does not apply to the `feature` branch
+
+---
+ files/ruby/feature.rb | 5 +++++
+ 1 file changed, 5 insertions(+)
+ create mode 100644 files/ruby/feature.rb
+
+diff --git a/files/ruby/feature.rb b/files/ruby/feature.rb
+new file mode 100644
+index 0000000..fef26e4
+--- /dev/null
++++ b/files/ruby/feature.rb
+@@ -0,0 +1,5 @@
++class Feature
++  def bar
++    puts 'foo'
++  end
++end
+-- =
+
+2.19.1
+
+--=_MailMate_D2C4B06A-4F8D-4AAB-B247-C507E35AAED6_=
+Content-Disposition: attachment; filename=0001-A-commit-from-a-patch.patch
+Content-Transfer-Encoding: quoted-printable
+
+=46rom 3fee0042e610fb3563e4379e316704cb1210f3de Mon Sep 17 00:00:00 2001
+From: Patch user <patchuser@gitlab.org>
+Date: Thu, 18 Oct 2018 13:40:35 +0200
+Subject: [PATCH] A commit from a patch
+
+---
+ README | 2 ++
+ 1 file changed, 2 insertions(+)
+
+diff --git a/README b/README
+index 3742e48..e40a3b9 100644
+--- a/README
++++ b/README
+@@ -1 +1,3 @@
+ Sample repo for testing gitlab features
++
++This was applied in a patch!
+-- =
+
+2.19.1
+
+
+--=_MailMate_D2C4B06A-4F8D-4AAB-B247-C507E35AAED6_=
+Content-Disposition: attachment; filename=really-not-a-patch.png
+Content-Type: image/png
+Content-Transfer-Encoding: base64
+
+iVBORw0KGgoAAAANSUhEUgAAAjMAAAAfCAYAAAASo0ymAAABfGlDQ1BJQ0MgUHJvZmlsZQAAKJFj
+YGAqSSwoyGFhYGDIzSspCnJ3UoiIjFJgv8PAzcDDIMRgxSCemFxc4BgQ4MOAE3y7xsAIoi/rgsxK
+8/x506a1fP4WNq+ZclYlOrj1gQF3SmpxMgMDIweQnZxSnJwLZOcA2TrJBUUlQPYMIFu3vKQAxD4B
+ZIsUAR0IZN8BsdMh7A8gdhKYzcQCVhMS5AxkSwDZAkkQtgaInQ5hW4DYyRmJKUC2B8guiBvAgNPD
+RcHcwFLXkYC7SQa5OaUwO0ChxZOaFxoMcgcQyzB4MLgwKDCYMxgwWDLoMjiWpFaUgBQ65xdUFmWm
+Z5QoOAJDNlXBOT+3oLQktUhHwTMvWU9HwcjA0ACkDhRnEKM/B4FNZxQ7jxDLX8jAYKnMwMDcgxBL
+msbAsH0PA4PEKYSYyjwGBn5rBoZt5woSixLhDmf8xkKIX5xmbARh8zgxMLDe+///sxoDA/skBoa/
+E////73o//+/i4H2A+PsQA4AJHdp4IxrEg8AAAGcaVRYdFhNTDpjb20uYWRvYmUueG1wAAAAAAA8
+eDp4bXBtZXRhIHhtbG5zOng9ImFkb2JlOm5zOm1ldGEvIiB4OnhtcHRrPSJYTVAgQ29yZSA1LjQu
+MCI+CiAgIDxyZGY6UkRGIHhtbG5zOnJkZj0iaHR0cDovL3d3dy53My5vcmcvMTk5OS8wMi8yMi1y
+ZGYtc3ludGF4LW5zIyI+CiAgICAgIDxyZGY6RGVzY3JpcHRpb24gcmRmOmFib3V0PSIiCiAgICAg
+ICAgICAgIHhtbG5zOmV4aWY9Imh0dHA6Ly9ucy5hZG9iZS5jb20vZXhpZi8xLjAvIj4KICAgICAg
+ICAgPGV4aWY6UGl4ZWxYRGltZW5zaW9uPjU2MzwvZXhpZjpQaXhlbFhEaW1lbnNpb24+CiAgICAg
+ICAgIDxleGlmOlBpeGVsWURpbWVuc2lvbj4zMTwvZXhpZjpQaXhlbFlEaW1lbnNpb24+CiAgICAg
+IDwvcmRmOkRlc2NyaXB0aW9uPgogICA8L3JkZjpSREY+CjwveDp4bXBtZXRhPgpZ5vHZAAAS+ElE
+QVR4Ae2cC1QUV5rH/xnA1uZli02MiEHQqBMdTGB8ZIniA5xgfCTRycb1rBmdTHJGJ+toPBtzzGg2
+Rs3LdVTOYhKMcDgmDNHVNXKiGKJINCoqiXpUEFdB0CDKCtrSYp/Zr6q7muqmu+pWd7XgnFtH6Xrc
++h6/+92qr+69VQ9dqrvxd/CFE+AEOAFOgBPgBDiBB5TALx5Qu7nZnAAnwAlwApwAJ8AJiAR4MsMD
+gRPgBDgBToAT4AQeaAI8mXmgq48bzwlwApwAJ8AJcAI8meExwAlwApwAJ8AJcAIPNAGezDzQ1ceN
+5wQ4AU6AE+AEOIFgTwiamls87eb7OAFOgBPgBDgBToAT0I1ARHhXXWTxnhldMHIhnAAnwAlwApwA
+J9BRBIL+vOjfl7srt969577L63Zj1VGU/liHHn1j0I0xNbI1X8TRo5V4yNQLEQbGk7xawH6go/Sy
+W8hLBoqAL3EaKFtY5doaz6PkwCk8FN0H3f1oJx0d93r5wcpN13K2RhzbX4KKn4FH+vSAx65sXRX+
+YwgTYq5k72FUXqzChaoq1DQGI7Z3dwT6ai/oPbj/OJoNDyM6IsRvmL74odTe9LbPbwc7gQCDQZ9W
+5VFK0co52FKp7OW0N9di6sAI1B//G7YU3kHvEb+Gyah8jnTUWncYWdm7kf7GWrz0eIS0O+C/HaVX
+P8dsqPphL07dicFvxg6BQT/BnVSSfv76EqcdDcVafww5X1A7iRmGR/1oJ+pxrx9nT8z08sOT7IDv
+s9YiPzcf10InImlkfy9tLrD8Au5jABRY6w8j56vdbZIFfslxCG/bE5A1Idazqc2EpUVj/cwhfuvw
+xQ+l9qa3fX47eN8EWFC4cj4KKgdjadZiJATg5uUxUQ6JiEGYOQpm8X9bhiLtC4MRIcH2PCg4RBjv
+Mml7YgkOFRFGhnrMpQKHt6P06ubRbZzIy8f2radxVzeZnVmQfv76FKcdjSa4i2hBiL/NRDXu9ePs
+EZlefngUHuCdQcF0daOlRxcEeVUVYH5e9XbeA8aEF/HZZ5vw2Zo/wSyYqchPRz8csdbD70Zjt8kn
+P5Tam8726Ugu4KJaxam4TWixBUaVx8tk6vx3kSrps57HqtdWosI8Ge9/8BylMV4WR0u32WwICvLe
+7IWzjQnP4vPPn/UiKHC7O0qvfh4ZYOxB0lpCYb/N6Se5c0oKgL8a4rRjmNhATUhsQwblZsRsnnrc
+B4Az9PeD2eH7XjAQ/O67E7orFG8Dxm5iMnhNd+n3T6BWP9Tb2/2zvTNpkgb9PCYdOhjKINcxf4Y6
+YJQSquoTxdiVl4eTtwWrYjDzzYVIGyg+0zjNrC3NQ27JFUREGGC1Av/04qsY0ad9f1PD6d3IzdmJ
+k9cs4rlh5niMmTIL01PinLK0rHSE3trSTfikBMhIj8P3m5W5NJwrxqfr81AhsgP6Jk3GnDnP4VEp
+c7ReRM7H2agjpytqBM+/wZqPz0CA2NJiQMYfX8eIXu05KjFqvnwCuwv34shPZ3DNofexpIl4/l+m
+Y6BJ+13U7u9djEg0YR91L4sXL/MwzF/4KpJktjHp1eyvFee+244tW3ejWvTFiMeSnsZvZ09HQrir
+LyxxqsRNOsbkBxXWEgdV1D7WZhfjlqAkNgWzUyRtvv2qxr1mzmx2sPqhGvcOdZarJ1CwaQv2VV4X
+94TFDsfLf/ydS1wJB1iuG1rqw6He+0+A+Kn5a71cgjXritB7yh8oRmJl9jWh6JN1KL07DAvmP2vv
+UaKjavIEAbpykVnEssoaB6zl3HU2nP4auTsO42ZECt6YPzFgQ12q7c3dMMe2N/tY6s2LSI+7Wfhp
+iQO97fNotIadHoeZvJ3veluQSgk30Vps2ZiHq/1SkJ4UY99enYlz9lxEKmj/peLW+gqcPFWOmtuU
+0bgttqvFWPxRPiUyQHLaRExKG47elgvYlV2KZreymjbvs96WhjpUV5YiK1OZS/PpfCxebU9kho4Z
+h6eGRKH62E4sn7cOl5x4gtDFEEFJYATCRKe7wWAwiNuRkeHahvgc0Kr3rseuQ5QQ9R6MVOKcOiQG
+Fcd2Y/XCNahy6mUnbPf3CAookemWNA6TxsQD18qxYckK/CirODa9Wvy1onTDIqzOFRKZKKRmTEb6
+mEdFX0ovOLI00Q2NcariOpsf1InGGAe1peuwQkxkYpA+dSKG3iil+TKlKlYwHFaMey2cGXRREVY/
+2OKebsRVuzFvyXoxkXlsFF0PxgzGrZojFFeLcLih7fGK9brBWh/tvPX4tQr9+bH4a+gRjZZrtdj3
+5X40ygy1XS7DlkMXUA26Vjj2s8gTivrMRabfl1XWOGAt525D7Q+b6H6yDScrDXj+n1MDlsg49Sq2
+N2cp54o3+1jrzSlIZYWVH2sc6G2fivlMhxl6ZpjkIPmltzAvvb9Y+Fdb3sZHRRdwsqYJA2mSsLTE
+pMzCEnratF38Gr9/Z5u02+XXevOmuJ3+xgc0OdjRNTHzFTQ3W30OxI7SKziizMWC4vzdor8zaEJ1
+hshqFp7c/DY27C/H1oM1WDiWnrwMsXhp0WIqZ0PhX15BQcsYzKMnL+H27OvSf+p7WPVCNHo5ey5e
+xIQ9H2LpF2dw4mITEmT1pkVH34w/4Z0ZT4in/Lr3Oiz/ohyFJeeROMkeG0x6NfhrOVeI7GOUNZvH
+YcWqWYhxZNy/faEGV++1J6RcH+yeMvkhE6es9woKs8updBTmf/guknrS6uSn8Om/LcNBeT4mk8ey
+qhr3Gjiz6ANY/WCMe+rf2/Gf+aQ6CnNXrUZKL3vlPjehGAvezkPWl98jef5ocS6L1uuGcn3IvDUM
+wpLPN8l2yFZ158for3EQpowyYsOhYpRdnoE0R+/22ZLvROOmpSU75vcwypO5xMxFdo7vq6xxwFqu
+zZKudOuoKs2iB4QjQOhwLP/gtbae7rZiuq6ptjeZNmX7tNebTLSHVe38lOPAP/vY35X24IrCLt2S
+mcRf9XOq6ZtIs8iLahHipc/Aamt1lm2/Yp/auicnE5HPP4PEuBiYzCaEh0tjLu3PYN3TEXoVuViq
+cbyGrDdPxNOy5CHp2QyE7f8UNxvc72RW2Mm1ihOA29+qWUlQfmR6BIaLJ1D4zQn878+30KVLF9xt
+qGcX0K6k0J1jRMYEeyIjHH40JR19KZmpOHwSFkpmhBrUplfd35qfjguqkD57ijOREbaDwmNpsLP9
+olgf7Yt73aPND0BRr+UmLguaaHhxmJDICEtQLMZNiMfBHRfs2378VY57QbA6Zyb1rH6wxr3lOs6K
+TeA6DnyTgzN37deGLtRHKw7FVV+B0Plrf0NG23VDsT6YnJUX0osfu79Dxv8GOLQNRSWVSBPe2rHV
+YB9dc4HhGDHQca3UxM/uj75c5Iw8rDPHgdbrJA3Hf/UBVogqB2P5XymR8Tys4MEo/3eptzcV+3yo
+N0WrWTnLhCjGgT/2hfbDw/7fymWWtq3qkMwIN7EYmGXzLIK62qentkJ7Dmbsn46Zo05Rd+kZFGyk
+/w5bU//1Lcwa21/hjYI2p3xZ018vAxdqYOK3D4mXS1sLN6M3OVFRXUe3mUEuPTDSJCqX8j44fLqA
+es8KhYsf5VKx8TCRIS3/d8cHSfJTTOguD1RbM3V5uy5a9ar5GxxiT+mMXdVCmaE+XE1V3GL3g0Gv
+ozLND0e7xMG9VuHc+7OocWaygtUPKscU91KQmyktratDg8yIoQPiYe1pdvJib78M9SHTw7qqJz8w
++GtIGIHU0G2UwBSjlpIZ0/mDKCNj+05NRS/JaA38hIRWz+u4ZILir4Y4YIoXj8rOYN/RK5g98hGP
+Rzt+pwf7NNUbgwesnEVRDHHgo33ig7jR5P0lIgZXlIqo3QGUznU91jZ87bpf61aQCWl/eBfjZjXh
+Wn0dzh7dg62F5diXuxHJIz6ENPKkVaxq+UDpVeJCx8ShePfx+LvN4li4uW9vl0SmzYe7NODkx0Jv
+qP2PkMiEplD36xxn96u16r/x2oqdfghuQYvwgCx1GXUJx2O0WUH+ifb6rNe7v9INv5U1b/YLnAON
+L34o6XUcu3NbNrmIVAUbJZAOvQH/8c6ZSTWrH1SOKe4lZt3HYslb45RN0Np+JdnKUjUe1YcfWPyl
+F55TnomnyfblKKtqRJ/9B8hWI9JGDmizWfKRSZ7jNOmcNin+rZE898ubU6B0zL2A+/WPtZxTMBA2
+6hW8P6Mr3l9I8602voeEuL86hyllxdhXJRvYz1AsqWgf6RIXLfWmpE2yXY2zXIZkg3yftC4d02Sf
+EVP/YxOmSjIC8KtpArBe+g1B9ueYkGAPF2ubVbzxBRkj0CtuEFJnvI7X0qJItZib+2VCR+n1arQx
+CoNC6ei1gzgpe+y8VLJXfBvIZHTPNe/Zh5munUKdkED7utju2S8w/eKciQxNtcS3+d/6KpHOE+ry
+OkrLapwyGs+WoYK2zMMG2IcCNOtV9ze6n314c9fXB8QhB6dyetK0WKVW17ZXlzXNfqhoNXRFNBW5
+tX+fbPJ1E04d9n+ISdCsGPeiaeqcxWJqf1j9YI17Q6jIBZXf4Uf5TFfRDrf6DeB1Q81tUA+0+NTp
+b7vU4i8ZlTBivPhCwPaNK7H5EA24xY7Hk455RaLNGuWp++lDCWNvDDXTeTdui30/LhJY44C1nEx4
+j2jqATA9gQULhCTYguwlmaj153Kg5IdMr7Cq3t7osztK9uldbz7wc3PJddMn+yy4dO4sTp87j0Z/
+7l2ulrhsud8tXQ66bFBW508s2JrP40BJFVqNIWi9Qm/R0HL820JEVhthae2G4eNHoyd1X53bthSr
+C7siffpY/DLOhObKE8gvEl7JHIwwD7mPKEjhT0fpVTBJdsiM0S8Mw57ccmQtXoHrr05ExNVjyN4h
+8IlCxuj+srLCagT6D6LErqYWGz7OwoRkupHTNWzI+AntXkF2O9F10xGM1afykEnjeKm/DMdPO3Kw
+p1KYgeDfUpa7DDmWlzHIeAVbc4tFYRmjHU+LmvWq+2tKfg6TzKXYdSof81bWYm76UIS0/Izvs7ch
+ir4wPduPL+d6JaHZD6+S7AeC4jBhagzKqN5XvJeFuVOScP2Hv2F7W16oIqD9Yda4t5+pzrm9Bg97
+mP1gjHuaN/Tiqyko21iKtQsXY9JLk9GPPlF/4+oZFO0oxZ0xC7H+ZZovQove1w0P3ins0osfu7+i
+MT0T8UwsUFBzXZxDlJw+0rULXwM/Bef8PBSKfv1p7JkmK/9l5S2MGRBGHUiPY/KkJ+jxhzEOmMvJ
+TBWzS/qca+IsLEg7h7VF5Vi6thhZi8Y5O45lpRlWlfygeyPj/c2pSMk+3euNlbPTOuUVX+yjN5Iz
+V68BvaQcsC//sycz3UOc49OungoZhudUSz4B2Fp/kj5v7TqEUX1oJ3IOCdKiaLIoJTMU85GxifS0
+UYw9X+Vhj6QoNB6z//x7nyZxdZRee0+FOpeYsfPwhiUTH1F3ccHG/3J4HI+5y15Hon1mo0RB/H38
+hdcx7cYn2H7sCLZXHrEfG/o0JTPyySoup7TfoGD83bKXUf/OZpQV5tF/oUg80tMM2FN0hiZu+76Y
+B0RR1/dm7HOImDTvPaRK3xLyQa+6vyZMX/U+IrPX0TyrUmTT6/D2JQZzI+XZL1ucOk5W/tHkB5ve
+gdMWY279h8g+dATZmUK9RuGpUTQBmF61lb62rWyU61HWuJfOUucslVT+ZfWDNe57jpyDVcEmrMnc
+iV1fbG5THhqDaU887Nxmv26w1YdTMOOKXvxY/bWbZcTwKSkoyBRiPh4TnnyknbXs8gLDhWayI2nu
+Msy4uw4FdM3aVUkmmkORQcmMsLDGAWu5IMfVq6usVztx5kJMOruIHnjy8GXZUMxOFrqKtC7KfrC2
+N1b72OuNzQ9Wfqz3Lc32Ob6kLSQzkarzG9l8ci/10KW6G39339nU7D645l4i0Ns2WCy36UuoNljv
+BcFkivCSSOltR0fppcze0kTdb9T3Rf/Ce5p8fHrQysOKxkZ7b4zR5J/Oqu1vY8UOA5Z+thRx5EvT
+PRvN+aC30IRrZLtFP71y0VZLI+gNfhho+NJIyR119AV40d8PS2Oj+GhgECbKeWQXYJd0Es/qB3vc
+E+uGJqpcA4KDDAj3CKfj2q9O2GRiWPyVFVdd1VueqkJNBVjjgLWcJuWdurC+9aY/P//tiwj3fwqJ
+UIWdNJnp1NHFjfNAwJ7MAG9mvgvpzVAPxfguToAT4AQ4AU7ASUCvZIZ9mMmpmq9wAu0J3Gu1z9Bk
+famovQS+hxPgBDgBToAT8I0A75nxjRs/y42ApaEGV24Go08CfYzP7Rjf5AQ4AU6AE+AEPBHQq2fG
+YzLjSSHfxwlwApwAJ8AJcAKcQGck8IvOaBS3iRPgBDgBToAT4AQ4AVYCPJlhJcXLcQKcACfACXAC
+nECnJMCTmU5ZLdwoToAT4AQ4AU6AE2AlwJMZVlK8HCfACXACnAAnwAl0SgI8memU1cKN4gQ4AU6A
+E+AEOAFWAv8PxvdR0yK8jugAAAAASUVORK5CYII=
+
+--=_MailMate_D2C4B06A-4F8D-4AAB-B247-C507E35AAED6_=--
diff --git a/spec/fixtures/emails/merge_request_with_conflicting_patch.eml b/spec/fixtures/emails/merge_request_with_conflicting_patch.eml
new file mode 100644
index 00000000000..ddfdfe9e24a
--- /dev/null
+++ b/spec/fixtures/emails/merge_request_with_conflicting_patch.eml
@@ -0,0 +1,45 @@
+From: "Jake the Dog" <jake@adventuretime.ooo>
+To: incoming+gitlabhq/gitlabhq+merge-request+auth_token@appmail.adventuretime.ooo
+Subject: feature
+Date: Wed, 31 Oct 2018 17:27:52 +0100
+X-Mailer: MailMate (1.12r5523)
+Message-ID: <7BE7C2E6-F0D9-4C85-9F55-B2A4BA01BFEC@gitlab.com>
+MIME-Version: 1.0
+Content-Type: multipart/mixed;
+ boundary="=_MailMate_D2C4B06A-4F8D-4AAB-B247-C507E35AAED6_="
+
+--=_MailMate_D2C4B06A-4F8D-4AAB-B247-C507E35AAED6_=
+
+This does not apply
+
+--=_MailMate_D2C4B06A-4F8D-4AAB-B247-C507E35AAED6_=
+Content-Disposition: attachment;
+ filename=0002-This-does-not-apply-to-the-feature-branch.patch
+Content-Transfer-Encoding: quoted-printable
+
+=46rom 00c68c2b4f954370ce82a1162bc29c13f524897e Mon Sep 17 00:00:00 2001
+From: Patch user <patchuser@gitlab.org>
+Date: Mon, 22 Oct 2018 11:05:48 +0200
+Subject: [PATCH] This does not apply to the `feature` branch
+
+---
+ files/ruby/feature.rb | 5 +++++
+ 1 file changed, 5 insertions(+)
+ create mode 100644 files/ruby/feature.rb
+
+diff --git a/files/ruby/feature.rb b/files/ruby/feature.rb
+new file mode 100644
+index 0000000..fef26e4
+--- /dev/null
++++ b/files/ruby/feature.rb
+@@ -0,0 +1,5 @@
++class Feature
++  def bar
++    puts 'foo'
++  end
++end
+-- =
+
+2.19.1
+
+--=_MailMate_D2C4B06A-4F8D-4AAB-B247-C507E35AAED6_=--
diff --git a/spec/fixtures/emails/merge_request_with_patch_and_target_branch.eml b/spec/fixtures/emails/merge_request_with_patch_and_target_branch.eml
new file mode 100644
index 00000000000..965658721cd
--- /dev/null
+++ b/spec/fixtures/emails/merge_request_with_patch_and_target_branch.eml
@@ -0,0 +1,44 @@
+From: "Jake the Dog" <jake@adventuretime.ooo>
+To: incoming+gitlabhq/gitlabhq+merge-request+auth_token@appmail.adventuretime.ooo
+Subject: new-branch-with-a-patch
+Date: Wed, 24 Oct 2018 16:39:49 +0200
+X-Mailer: MailMate (1.12r5523)
+Message-ID: <F1F36291-728D-4E8F-AFEB-C398B8D9BB4E@gitlab.com>
+MIME-Version: 1.0
+Content-Type: multipart/mixed;
+ boundary="=_MailMate_D2C4B06A-4F8D-4AAB-B247-C507E35AAED6_="
+
+
+--=_MailMate_D2C4B06A-4F8D-4AAB-B247-C507E35AAED6_=
+
+This applies nicely to a branch freshly created from the root-ref
+
+The other attachments in this email are ignored
+
+/target_branch with-codeowners
+
+
+--=_MailMate_D2C4B06A-4F8D-4AAB-B247-C507E35AAED6_=
+Content-Disposition: attachment; filename=0001-A-commit-from-a-patch.patch
+Content-Transfer-Encoding: quoted-printable
+
+=46rom 3fee0042e610fb3563e4379e316704cb1210f3de Mon Sep 17 00:00:00 2001
+From: Patch user <patchuser@gitlab.org>
+Date: Thu, 18 Oct 2018 13:40:35 +0200
+Subject: [PATCH] A commit from a patch
+
+---
+ README | 2 ++
+ 1 file changed, 2 insertions(+)
+
+diff --git a/README b/README
+index 3742e48..e40a3b9 100644
+--- a/README
++++ b/README
+@@ -1 +1,3 @@
+ Sample repo for testing gitlab features
++
++This was applied in a patch!
+-- =
+
+2.19.1
diff --git a/spec/fixtures/emails/valid_merge_request_with_patch.eml b/spec/fixtures/emails/valid_merge_request_with_patch.eml
new file mode 100644
index 00000000000..143fa77d1fa
--- /dev/null
+++ b/spec/fixtures/emails/valid_merge_request_with_patch.eml
@@ -0,0 +1,151 @@
+From: "Jake the Dog" <jake@adventuretime.ooo>
+To: incoming+gitlabhq/gitlabhq+merge-request+auth_token@appmail.adventuretime.ooo
+Subject: new-branch-with-a-patch
+Date: Wed, 24 Oct 2018 16:39:49 +0200
+X-Mailer: MailMate (1.12r5523)
+Message-ID: <F1F36291-728D-4E8F-AFEB-C398B8D9BB4E@gitlab.com>
+MIME-Version: 1.0
+Content-Type: multipart/mixed;
+ boundary="=_MailMate_D2C4B06A-4F8D-4AAB-B247-C507E35AAED6_="
+
+
+--=_MailMate_D2C4B06A-4F8D-4AAB-B247-C507E35AAED6_=
+
+This applies nicely to a branch freshly created from the root-ref
+
+The other attachments in this email are ignored
+
+
+--=_MailMate_D2C4B06A-4F8D-4AAB-B247-C507E35AAED6_=
+Content-Disposition: attachment; filename=0001-A-commit-from-a-patch.patch
+Content-Transfer-Encoding: quoted-printable
+
+=46rom 3fee0042e610fb3563e4379e316704cb1210f3de Mon Sep 17 00:00:00 2001
+From: Patch user <patchuser@gitlab.org>
+Date: Thu, 18 Oct 2018 13:40:35 +0200
+Subject: [PATCH] A commit from a patch
+
+---
+ README | 2 ++
+ 1 file changed, 2 insertions(+)
+
+diff --git a/README b/README
+index 3742e48..e40a3b9 100644
+--- a/README
++++ b/README
+@@ -1 +1,3 @@
+ Sample repo for testing gitlab features
++
++This was applied in a patch!
+-- =
+
+2.19.1
+
+
+--=_MailMate_D2C4B06A-4F8D-4AAB-B247-C507E35AAED6_=
+Content-Disposition: attachment; filename=really-not-a-patch.png
+Content-Type: image/png
+Content-Transfer-Encoding: base64
+
+iVBORw0KGgoAAAANSUhEUgAAAjMAAAAfCAYAAAASo0ymAAABfGlDQ1BJQ0MgUHJvZmlsZQAAKJFj
+YGAqSSwoyGFhYGDIzSspCnJ3UoiIjFJgv8PAzcDDIMRgxSCemFxc4BgQ4MOAE3y7xsAIoi/rgsxK
+8/x506a1fP4WNq+ZclYlOrj1gQF3SmpxMgMDIweQnZxSnJwLZOcA2TrJBUUlQPYMIFu3vKQAxD4B
+ZIsUAR0IZN8BsdMh7A8gdhKYzcQCVhMS5AxkSwDZAkkQtgaInQ5hW4DYyRmJKUC2B8guiBvAgNPD
+RcHcwFLXkYC7SQa5OaUwO0ChxZOaFxoMcgcQyzB4MLgwKDCYMxgwWDLoMjiWpFaUgBQ65xdUFmWm
+Z5QoOAJDNlXBOT+3oLQktUhHwTMvWU9HwcjA0ACkDhRnEKM/B4FNZxQ7jxDLX8jAYKnMwMDcgxBL
+msbAsH0PA4PEKYSYyjwGBn5rBoZt5woSixLhDmf8xkKIX5xmbARh8zgxMLDe+///sxoDA/skBoa/
+E////73o//+/i4H2A+PsQA4AJHdp4IxrEg8AAAGcaVRYdFhNTDpjb20uYWRvYmUueG1wAAAAAAA8
+eDp4bXBtZXRhIHhtbG5zOng9ImFkb2JlOm5zOm1ldGEvIiB4OnhtcHRrPSJYTVAgQ29yZSA1LjQu
+MCI+CiAgIDxyZGY6UkRGIHhtbG5zOnJkZj0iaHR0cDovL3d3dy53My5vcmcvMTk5OS8wMi8yMi1y
+ZGYtc3ludGF4LW5zIyI+CiAgICAgIDxyZGY6RGVzY3JpcHRpb24gcmRmOmFib3V0PSIiCiAgICAg
+ICAgICAgIHhtbG5zOmV4aWY9Imh0dHA6Ly9ucy5hZG9iZS5jb20vZXhpZi8xLjAvIj4KICAgICAg
+ICAgPGV4aWY6UGl4ZWxYRGltZW5zaW9uPjU2MzwvZXhpZjpQaXhlbFhEaW1lbnNpb24+CiAgICAg
+ICAgIDxleGlmOlBpeGVsWURpbWVuc2lvbj4zMTwvZXhpZjpQaXhlbFlEaW1lbnNpb24+CiAgICAg
+IDwvcmRmOkRlc2NyaXB0aW9uPgogICA8L3JkZjpSREY+CjwveDp4bXBtZXRhPgpZ5vHZAAAS+ElE
+QVR4Ae2cC1QUV5rH/xnA1uZli02MiEHQqBMdTGB8ZIniA5xgfCTRycb1rBmdTHJGJ+toPBtzzGg2
+Rs3LdVTOYhKMcDgmDNHVNXKiGKJINCoqiXpUEFdB0CDKCtrSYp/Zr6q7muqmu+pWd7XgnFtH6Xrc
++h6/+92qr+69VQ9dqrvxd/CFE+AEOAFOgBPgBDiBB5TALx5Qu7nZnAAnwAlwApwAJ8AJiAR4MsMD
+gRPgBDgBToAT4AQeaAI8mXmgq48bzwlwApwAJ8AJcAI8meExwAlwApwAJ8AJcAIPNAGezDzQ1ceN
+5wQ4AU6AE+AEOIFgTwiamls87eb7OAFOgBPgBDgBToAT0I1ARHhXXWTxnhldMHIhnAAnwAlwApwA
+J9BRBIL+vOjfl7srt969577L63Zj1VGU/liHHn1j0I0xNbI1X8TRo5V4yNQLEQbGk7xawH6go/Sy
+W8hLBoqAL3EaKFtY5doaz6PkwCk8FN0H3f1oJx0d93r5wcpN13K2RhzbX4KKn4FH+vSAx65sXRX+
+YwgTYq5k72FUXqzChaoq1DQGI7Z3dwT6ai/oPbj/OJoNDyM6IsRvmL74odTe9LbPbwc7gQCDQZ9W
+5VFK0co52FKp7OW0N9di6sAI1B//G7YU3kHvEb+Gyah8jnTUWncYWdm7kf7GWrz0eIS0O+C/HaVX
+P8dsqPphL07dicFvxg6BQT/BnVSSfv76EqcdDcVafww5X1A7iRmGR/1oJ+pxrx9nT8z08sOT7IDv
+s9YiPzcf10InImlkfy9tLrD8Au5jABRY6w8j56vdbZIFfslxCG/bE5A1Idazqc2EpUVj/cwhfuvw
+xQ+l9qa3fX47eN8EWFC4cj4KKgdjadZiJATg5uUxUQ6JiEGYOQpm8X9bhiLtC4MRIcH2PCg4RBjv
+Mml7YgkOFRFGhnrMpQKHt6P06ubRbZzIy8f2radxVzeZnVmQfv76FKcdjSa4i2hBiL/NRDXu9ePs
+EZlefngUHuCdQcF0daOlRxcEeVUVYH5e9XbeA8aEF/HZZ5vw2Zo/wSyYqchPRz8csdbD70Zjt8kn
+P5Tam8726Ugu4KJaxam4TWixBUaVx8tk6vx3kSrps57HqtdWosI8Ge9/8BylMV4WR0u32WwICvLe
+7IWzjQnP4vPPn/UiKHC7O0qvfh4ZYOxB0lpCYb/N6Se5c0oKgL8a4rRjmNhATUhsQwblZsRsnnrc
+B4Az9PeD2eH7XjAQ/O67E7orFG8Dxm5iMnhNd+n3T6BWP9Tb2/2zvTNpkgb9PCYdOhjKINcxf4Y6
+YJQSquoTxdiVl4eTtwWrYjDzzYVIGyg+0zjNrC3NQ27JFUREGGC1Av/04qsY0ad9f1PD6d3IzdmJ
+k9cs4rlh5niMmTIL01PinLK0rHSE3trSTfikBMhIj8P3m5W5NJwrxqfr81AhsgP6Jk3GnDnP4VEp
+c7ReRM7H2agjpytqBM+/wZqPz0CA2NJiQMYfX8eIXu05KjFqvnwCuwv34shPZ3DNofexpIl4/l+m
+Y6BJ+13U7u9djEg0YR91L4sXL/MwzF/4KpJktjHp1eyvFee+244tW3ejWvTFiMeSnsZvZ09HQrir
+LyxxqsRNOsbkBxXWEgdV1D7WZhfjlqAkNgWzUyRtvv2qxr1mzmx2sPqhGvcOdZarJ1CwaQv2VV4X
+94TFDsfLf/ydS1wJB1iuG1rqw6He+0+A+Kn5a71cgjXritB7yh8oRmJl9jWh6JN1KL07DAvmP2vv
+UaKjavIEAbpykVnEssoaB6zl3HU2nP4auTsO42ZECt6YPzFgQ12q7c3dMMe2N/tY6s2LSI+7Wfhp
+iQO97fNotIadHoeZvJ3veluQSgk30Vps2ZiHq/1SkJ4UY99enYlz9lxEKmj/peLW+gqcPFWOmtuU
+0bgttqvFWPxRPiUyQHLaRExKG47elgvYlV2KZreymjbvs96WhjpUV5YiK1OZS/PpfCxebU9kho4Z
+h6eGRKH62E4sn7cOl5x4gtDFEEFJYATCRKe7wWAwiNuRkeHahvgc0Kr3rseuQ5QQ9R6MVOKcOiQG
+Fcd2Y/XCNahy6mUnbPf3CAookemWNA6TxsQD18qxYckK/CirODa9Wvy1onTDIqzOFRKZKKRmTEb6
+mEdFX0ovOLI00Q2NcariOpsf1InGGAe1peuwQkxkYpA+dSKG3iil+TKlKlYwHFaMey2cGXRREVY/
+2OKebsRVuzFvyXoxkXlsFF0PxgzGrZojFFeLcLih7fGK9brBWh/tvPX4tQr9+bH4a+gRjZZrtdj3
+5X40ygy1XS7DlkMXUA26Vjj2s8gTivrMRabfl1XWOGAt525D7Q+b6H6yDScrDXj+n1MDlsg49Sq2
+N2cp54o3+1jrzSlIZYWVH2sc6G2fivlMhxl6ZpjkIPmltzAvvb9Y+Fdb3sZHRRdwsqYJA2mSsLTE
+pMzCEnratF38Gr9/Z5u02+XXevOmuJ3+xgc0OdjRNTHzFTQ3W30OxI7SKziizMWC4vzdor8zaEJ1
+hshqFp7c/DY27C/H1oM1WDiWnrwMsXhp0WIqZ0PhX15BQcsYzKMnL+H27OvSf+p7WPVCNHo5ey5e
+xIQ9H2LpF2dw4mITEmT1pkVH34w/4Z0ZT4in/Lr3Oiz/ohyFJeeROMkeG0x6NfhrOVeI7GOUNZvH
+YcWqWYhxZNy/faEGV++1J6RcH+yeMvkhE6es9woKs8updBTmf/guknrS6uSn8Om/LcNBeT4mk8ey
+qhr3Gjiz6ANY/WCMe+rf2/Gf+aQ6CnNXrUZKL3vlPjehGAvezkPWl98jef5ocS6L1uuGcn3IvDUM
+wpLPN8l2yFZ158for3EQpowyYsOhYpRdnoE0R+/22ZLvROOmpSU75vcwypO5xMxFdo7vq6xxwFqu
+zZKudOuoKs2iB4QjQOhwLP/gtbae7rZiuq6ptjeZNmX7tNebTLSHVe38lOPAP/vY35X24IrCLt2S
+mcRf9XOq6ZtIs8iLahHipc/Aamt1lm2/Yp/auicnE5HPP4PEuBiYzCaEh0tjLu3PYN3TEXoVuViq
+cbyGrDdPxNOy5CHp2QyE7f8UNxvc72RW2Mm1ihOA29+qWUlQfmR6BIaLJ1D4zQn878+30KVLF9xt
+qGcX0K6k0J1jRMYEeyIjHH40JR19KZmpOHwSFkpmhBrUplfd35qfjguqkD57ijOREbaDwmNpsLP9
+olgf7Yt73aPND0BRr+UmLguaaHhxmJDICEtQLMZNiMfBHRfs2378VY57QbA6Zyb1rH6wxr3lOs6K
+TeA6DnyTgzN37deGLtRHKw7FVV+B0Plrf0NG23VDsT6YnJUX0osfu79Dxv8GOLQNRSWVSBPe2rHV
+YB9dc4HhGDHQca3UxM/uj75c5Iw8rDPHgdbrJA3Hf/UBVogqB2P5XymR8Tys4MEo/3eptzcV+3yo
+N0WrWTnLhCjGgT/2hfbDw/7fymWWtq3qkMwIN7EYmGXzLIK62qentkJ7Dmbsn46Zo05Rd+kZFGyk
+/w5bU//1Lcwa21/hjYI2p3xZ018vAxdqYOK3D4mXS1sLN6M3OVFRXUe3mUEuPTDSJCqX8j44fLqA
+es8KhYsf5VKx8TCRIS3/d8cHSfJTTOguD1RbM3V5uy5a9ar5GxxiT+mMXdVCmaE+XE1V3GL3g0Gv
+ozLND0e7xMG9VuHc+7OocWaygtUPKscU91KQmyktratDg8yIoQPiYe1pdvJib78M9SHTw7qqJz8w
++GtIGIHU0G2UwBSjlpIZ0/mDKCNj+05NRS/JaA38hIRWz+u4ZILir4Y4YIoXj8rOYN/RK5g98hGP
+Rzt+pwf7NNUbgwesnEVRDHHgo33ig7jR5P0lIgZXlIqo3QGUznU91jZ87bpf61aQCWl/eBfjZjXh
+Wn0dzh7dg62F5diXuxHJIz6ENPKkVaxq+UDpVeJCx8ShePfx+LvN4li4uW9vl0SmzYe7NODkx0Jv
+qP2PkMiEplD36xxn96u16r/x2oqdfghuQYvwgCx1GXUJx2O0WUH+ifb6rNe7v9INv5U1b/YLnAON
+L34o6XUcu3NbNrmIVAUbJZAOvQH/8c6ZSTWrH1SOKe4lZt3HYslb45RN0Np+JdnKUjUe1YcfWPyl
+F55TnomnyfblKKtqRJ/9B8hWI9JGDmizWfKRSZ7jNOmcNin+rZE898ubU6B0zL2A+/WPtZxTMBA2
+6hW8P6Mr3l9I8602voeEuL86hyllxdhXJRvYz1AsqWgf6RIXLfWmpE2yXY2zXIZkg3yftC4d02Sf
+EVP/YxOmSjIC8KtpArBe+g1B9ueYkGAPF2ubVbzxBRkj0CtuEFJnvI7X0qJItZib+2VCR+n1arQx
+CoNC6ei1gzgpe+y8VLJXfBvIZHTPNe/Zh5munUKdkED7utju2S8w/eKciQxNtcS3+d/6KpHOE+ry
+OkrLapwyGs+WoYK2zMMG2IcCNOtV9ze6n314c9fXB8QhB6dyetK0WKVW17ZXlzXNfqhoNXRFNBW5
+tX+fbPJ1E04d9n+ISdCsGPeiaeqcxWJqf1j9YI17Q6jIBZXf4Uf5TFfRDrf6DeB1Q81tUA+0+NTp
+b7vU4i8ZlTBivPhCwPaNK7H5EA24xY7Hk455RaLNGuWp++lDCWNvDDXTeTdui30/LhJY44C1nEx4
+j2jqATA9gQULhCTYguwlmaj153Kg5IdMr7Cq3t7osztK9uldbz7wc3PJddMn+yy4dO4sTp87j0Z/
+7l2ulrhsud8tXQ66bFBW508s2JrP40BJFVqNIWi9Qm/R0HL820JEVhthae2G4eNHoyd1X53bthSr
+C7siffpY/DLOhObKE8gvEl7JHIwwD7mPKEjhT0fpVTBJdsiM0S8Mw57ccmQtXoHrr05ExNVjyN4h
+8IlCxuj+srLCagT6D6LErqYWGz7OwoRkupHTNWzI+AntXkF2O9F10xGM1afykEnjeKm/DMdPO3Kw
+p1KYgeDfUpa7DDmWlzHIeAVbc4tFYRmjHU+LmvWq+2tKfg6TzKXYdSof81bWYm76UIS0/Izvs7ch
+ir4wPduPL+d6JaHZD6+S7AeC4jBhagzKqN5XvJeFuVOScP2Hv2F7W16oIqD9Yda4t5+pzrm9Bg97
+mP1gjHuaN/Tiqyko21iKtQsXY9JLk9GPPlF/4+oZFO0oxZ0xC7H+ZZovQove1w0P3ins0osfu7+i
+MT0T8UwsUFBzXZxDlJw+0rULXwM/Bef8PBSKfv1p7JkmK/9l5S2MGRBGHUiPY/KkJ+jxhzEOmMvJ
+TBWzS/qca+IsLEg7h7VF5Vi6thhZi8Y5O45lpRlWlfygeyPj/c2pSMk+3euNlbPTOuUVX+yjN5Iz
+V68BvaQcsC//sycz3UOc49OungoZhudUSz4B2Fp/kj5v7TqEUX1oJ3IOCdKiaLIoJTMU85GxifS0
+UYw9X+Vhj6QoNB6z//x7nyZxdZRee0+FOpeYsfPwhiUTH1F3ccHG/3J4HI+5y15Hon1mo0RB/H38
+hdcx7cYn2H7sCLZXHrEfG/o0JTPyySoup7TfoGD83bKXUf/OZpQV5tF/oUg80tMM2FN0hiZu+76Y
+B0RR1/dm7HOImDTvPaRK3xLyQa+6vyZMX/U+IrPX0TyrUmTT6/D2JQZzI+XZL1ucOk5W/tHkB5ve
+gdMWY279h8g+dATZmUK9RuGpUTQBmF61lb62rWyU61HWuJfOUucslVT+ZfWDNe57jpyDVcEmrMnc
+iV1fbG5THhqDaU887Nxmv26w1YdTMOOKXvxY/bWbZcTwKSkoyBRiPh4TnnyknbXs8gLDhWayI2nu
+Msy4uw4FdM3aVUkmmkORQcmMsLDGAWu5IMfVq6usVztx5kJMOruIHnjy8GXZUMxOFrqKtC7KfrC2
+N1b72OuNzQ9Wfqz3Lc32Ob6kLSQzkarzG9l8ci/10KW6G39339nU7D645l4i0Ns2WCy36UuoNljv
+BcFkivCSSOltR0fppcze0kTdb9T3Rf/Ce5p8fHrQysOKxkZ7b4zR5J/Oqu1vY8UOA5Z+thRx5EvT
+PRvN+aC30IRrZLtFP71y0VZLI+gNfhho+NJIyR119AV40d8PS2Oj+GhgECbKeWQXYJd0Es/qB3vc
+E+uGJqpcA4KDDAj3CKfj2q9O2GRiWPyVFVdd1VueqkJNBVjjgLWcJuWdurC+9aY/P//tiwj3fwqJ
+UIWdNJnp1NHFjfNAwJ7MAG9mvgvpzVAPxfguToAT4AQ4AU7ASUCvZIZ9mMmpmq9wAu0J3Gu1z9Bk
+famovQS+hxPgBDgBToAT8I0A75nxjRs/y42ApaEGV24Go08CfYzP7Rjf5AQ4AU6AE+AEPBHQq2fG
+YzLjSSHfxwlwApwAJ8AJcAKcQGck8IvOaBS3iRPgBDgBToAT4AQ4AVYCPJlhJcXLcQKcACfACXAC
+nECnJMCTmU5ZLdwoToAT4AQ4AU6AE2AlwJMZVlK8HCfACXACnAAnwAl0SgI8memU1cKN4gQ4AU6A
+E+AEOAFWAv8PxvdR0yK8jugAAAAASUVORK5CYII=
+--=_MailMate_D2C4B06A-4F8D-4AAB-B247-C507E35AAED6_=--
diff --git a/spec/fixtures/patchfiles/0001-A-commit-from-a-patch.patch b/spec/fixtures/patchfiles/0001-A-commit-from-a-patch.patch
new file mode 100644
index 00000000000..cc38682a0ab
--- /dev/null
+++ b/spec/fixtures/patchfiles/0001-A-commit-from-a-patch.patch
@@ -0,0 +1,19 @@
+From 3fee0042e610fb3563e4379e316704cb1210f3de Mon Sep 17 00:00:00 2001
+From: Patch User <patchuser@gitlab.org>
+Date: Thu, 18 Oct 2018 13:40:35 +0200
+Subject: [PATCH] A commit from a patch
+
+---
+ README | 2 ++
+ 1 file changed, 2 insertions(+)
+
+diff --git a/README b/README
+index 3742e48..e40a3b9 100644
+--- a/README
++++ b/README
+@@ -1 +1,3 @@
+ Sample repo for testing gitlab features
++
++This was applied in a patch!
+--
+2.19.1
diff --git a/spec/fixtures/patchfiles/0001-This-does-not-apply-to-the-feature-branch.patch b/spec/fixtures/patchfiles/0001-This-does-not-apply-to-the-feature-branch.patch
new file mode 100644
index 00000000000..905002ae898
--- /dev/null
+++ b/spec/fixtures/patchfiles/0001-This-does-not-apply-to-the-feature-branch.patch
@@ -0,0 +1,23 @@
+From 00c68c2b4f954370ce82a1162bc29c13f524897e Mon Sep 17 00:00:00 2001
+From: Patch User <patchuser@gitlab.org>
+Date: Mon, 22 Oct 2018 11:05:48 +0200
+Subject: [PATCH] This does not apply to the `feature` branch
+
+---
+ files/ruby/feature.rb | 5 +++++
+ 1 file changed, 5 insertions(+)
+ create mode 100644 files/ruby/feature.rb
+
+diff --git a/files/ruby/feature.rb b/files/ruby/feature.rb
+new file mode 100644
+index 0000000..fef26e4
+--- /dev/null
++++ b/files/ruby/feature.rb
+@@ -0,0 +1,5 @@
++class Feature
++  def bar
++    puts 'foo'
++  end
++end
+--
+2.19.1
diff --git a/spec/lib/gitlab/email/handler/create_merge_request_handler_spec.rb b/spec/lib/gitlab/email/handler/create_merge_request_handler_spec.rb
index ace3104f36f..f276f1a8ddf 100644
--- a/spec/lib/gitlab/email/handler/create_merge_request_handler_spec.rb
+++ b/spec/lib/gitlab/email/handler/create_merge_request_handler_spec.rb
@@ -93,5 +93,74 @@ describe Gitlab::Email::Handler::CreateMergeRequestHandler do
         end
       end
     end
+
+    context 'when the email contains patch attachments' do
+      let(:email_raw) { fixture_file("emails/valid_merge_request_with_patch.eml") }
+
+      it 'creates the source branch and applies the patches' do
+        receiver.execute
+
+        branch = project.repository.find_branch('new-branch-with-a-patch')
+
+        expect(branch).not_to be_nil
+        expect(branch.dereferenced_target.message).to include('A commit from a patch')
+      end
+
+      it 'creates the merge request' do
+        expect { receiver.execute }
+          .to change { project.merge_requests.where(source_branch: 'new-branch-with-a-patch').size }.by(1)
+      end
+
+      it 'does not mention the patches in the created merge request' do
+        receiver.execute
+
+        merge_request = project.merge_requests.find_by!(source_branch: 'new-branch-with-a-patch')
+
+        expect(merge_request.description).not_to include('0001-A-commit-from-a-patch.patch')
+      end
+
+      context 'when the patch could not be applied' do
+        let(:email_raw) { fixture_file("emails/merge_request_with_conflicting_patch.eml") }
+
+        it 'raises an error' do
+          expect { receiver.execute }.to raise_error(Gitlab::Email::InvalidAttachment)
+        end
+      end
+
+      context 'when specifying the target branch using quick actions' do
+        let(:email_raw) { fixture_file('emails/merge_request_with_patch_and_target_branch.eml') }
+
+        it 'creates the merge request with the correct target branch' do
+          receiver.execute
+
+          merge_request = project.merge_requests.find_by!(source_branch: 'new-branch-with-a-patch')
+
+          expect(merge_request.target_branch).to eq('with-codeowners')
+        end
+
+        it 'based the merge request of the target_branch' do
+          receiver.execute
+
+          merge_request = project.merge_requests.find_by!(source_branch: 'new-branch-with-a-patch')
+
+          expect(merge_request.diff_base_commit).to eq(project.repository.commit('with-codeowners'))
+        end
+      end
+    end
+  end
+
+  describe '#patch_attachments' do
+    let(:email_raw) { fixture_file('emails/merge_request_multiple_patches.eml') }
+    let(:mail) { Mail::Message.new(email_raw) }
+    subject(:handler) { described_class.new(mail, mail_key) }
+
+    it 'orders attachments ending in `.patch` by name' do
+      expected_filenames = ["0001-A-commit-from-a-patch.patch",
+                            "0002-This-does-not-apply-to-the-feature-branch.patch"]
+
+      attachments = handler.__send__(:patch_attachments).map(&:filename)
+
+      expect(attachments).to eq(expected_filenames)
+    end
   end
 end
diff --git a/spec/lib/gitlab/git/patches/collection_spec.rb b/spec/lib/gitlab/git/patches/collection_spec.rb
new file mode 100644
index 00000000000..080be141c59
--- /dev/null
+++ b/spec/lib/gitlab/git/patches/collection_spec.rb
@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+require 'spec_helper'
+
+describe Gitlab::Git::Patches::Collection do
+  let(:patches_folder) { Rails.root.join('spec/fixtures/patchfiles') }
+  let(:patch_content1) do
+    File.read(File.join(patches_folder, "0001-This-does-not-apply-to-the-feature-branch.patch"))
+  end
+  let(:patch_content2) do
+    File.read(File.join(patches_folder, "0001-A-commit-from-a-patch.patch"))
+  end
+
+  subject(:collection) { described_class.new([patch_content1, patch_content2]) }
+
+  describe '#size' do
+    it 'combines the size of the patches' do
+      expect(collection.size).to eq(549.bytes + 424.bytes)
+    end
+  end
+
+  describe '#valid_size?' do
+    it 'is not valid if the total size is bigger than 2MB' do
+      expect(collection).to receive(:size).and_return(2500.kilobytes)
+
+      expect(collection).not_to be_valid_size
+    end
+  end
+end
diff --git a/spec/lib/gitlab/git/patches/commit_patches_spec.rb b/spec/lib/gitlab/git/patches/commit_patches_spec.rb
new file mode 100644
index 00000000000..760112155ce
--- /dev/null
+++ b/spec/lib/gitlab/git/patches/commit_patches_spec.rb
@@ -0,0 +1,49 @@
+# frozen_string_literal: true
+require 'spec_helper'
+
+describe Gitlab::Git::Patches::CommitPatches do
+  describe '#commit' do
+    let(:patches) do
+      patches_folder = Rails.root.join('spec/fixtures/patchfiles')
+      content_1 = File.read(File.join(patches_folder, "0001-This-does-not-apply-to-the-feature-branch.patch"))
+      content_2 = File.read(File.join(patches_folder, "0001-A-commit-from-a-patch.patch"))
+
+      Gitlab::Git::Patches::Collection.new([content_1, content_2])
+    end
+    let(:user) { build(:user) }
+    let(:branch_name) { 'branch-with-patches' }
+    let(:repository) { create(:project, :repository).repository }
+
+    subject(:commit_patches) do
+      described_class.new(user, repository, branch_name, patches)
+    end
+
+    it 'applies the patches' do
+      new_rev = commit_patches.commit
+
+      expect(repository.commit(new_rev)).not_to be_nil
+    end
+
+    it 'updates the branch cache' do
+      expect(repository).to receive(:after_create_branch)
+
+      commit_patches.commit
+    end
+
+    context 'when the repository does not exist' do
+      let(:repository) { create(:project).repository }
+
+      it 'raises the correct error' do
+        expect { commit_patches.commit }.to raise_error(Gitlab::Git::Repository::NoRepository)
+      end
+    end
+
+    context 'when the patch does not apply' do
+      let(:branch_name) { 'feature' }
+
+      it 'raises the correct error' do
+        expect { commit_patches.commit }.to raise_error(Gitlab::Git::CommandError)
+      end
+    end
+  end
+end
diff --git a/spec/lib/gitlab/git/patches/patch_spec.rb b/spec/lib/gitlab/git/patches/patch_spec.rb
new file mode 100644
index 00000000000..7466e853b65
--- /dev/null
+++ b/spec/lib/gitlab/git/patches/patch_spec.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+require 'spec_helper'
+
+describe Gitlab::Git::Patches::Patch do
+  let(:patches_folder) { Rails.root.join('spec/fixtures/patchfiles') }
+  let(:patch_content) do
+    File.read(File.join(patches_folder, "0001-This-does-not-apply-to-the-feature-branch.patch"))
+  end
+  let(:patch) { described_class.new(patch_content) }
+
+  describe '#size' do
+    it 'is correct' do
+      expect(patch.size).to eq(549.bytes)
+    end
+  end
+end
diff --git a/spec/lib/gitlab/gitaly_client/operation_service_spec.rb b/spec/lib/gitlab/gitaly_client/operation_service_spec.rb
index eaf64e3c9b4..b37fe2686b6 100644
--- a/spec/lib/gitlab/gitaly_client/operation_service_spec.rb
+++ b/spec/lib/gitlab/gitaly_client/operation_service_spec.rb
@@ -335,4 +335,37 @@ describe Gitlab::GitalyClient::OperationService do
       end
     end
   end
+
+  describe '#user_commit_patches' do
+    let(:patches_folder) { Rails.root.join('spec/fixtures/patchfiles') }
+    let(:patch_content) do
+      patch_names.map { |name| File.read(File.join(patches_folder, name)) }.join("\n")
+    end
+    let(:patch_names) { %w(0001-This-does-not-apply-to-the-feature-branch.patch) }
+    let(:branch_name) { 'branch-with-patches' }
+
+    subject(:commit_patches) do
+      client.user_commit_patches(user, branch_name, patch_content)
+    end
+
+    it 'applies the patch correctly' do
+      branch_update = commit_patches
+
+      expect(branch_update).to be_branch_created
+
+      commit = repository.commit(branch_update.newrev)
+      expect(commit.author_email).to eq('patchuser@gitlab.org')
+      expect(commit.committer_email).to eq(user.email)
+      expect(commit.message.chomp).to eq('This does not apply to the `feature` branch')
+    end
+
+    context 'when the patch could not be applied' do
+      let(:patch_names) { %w(0001-This-does-not-apply-to-the-feature-branch.patch) }
+      let(:branch_name) { 'feature' }
+
+      it 'raises the correct error' do
+        expect { commit_patches }.to raise_error(GRPC::FailedPrecondition)
+      end
+    end
+  end
 end
diff --git a/spec/lib/gitlab/quick_actions/extractor_spec.rb b/spec/lib/gitlab/quick_actions/extractor_spec.rb
index 0166f6c2ee0..873bb359d6e 100644
--- a/spec/lib/gitlab/quick_actions/extractor_spec.rb
+++ b/spec/lib/gitlab/quick_actions/extractor_spec.rb
@@ -272,5 +272,24 @@ describe Gitlab::QuickActions::Extractor do
       expect(commands).to be_empty
       expect(msg).to eq expected
     end
+
+    it 'limits to passed commands when they are passed' do
+      msg = <<~MSG.strip
+      Hello, we should only extract the commands passed
+      /reopen
+      /labels hello world
+      /power
+      MSG
+      expected_msg = <<~EXPECTED.strip
+      Hello, we should only extract the commands passed
+      /power
+      EXPECTED
+      expected_commands = [['reopen'], ['labels', 'hello world']]
+
+      msg, commands = extractor.extract_commands(msg, only: [:open, :labels])
+
+      expect(commands).to eq(expected_commands)
+      expect(msg).to eq expected_msg
+    end
   end
 end
diff --git a/spec/services/commits/commit_patch_service_spec.rb b/spec/services/commits/commit_patch_service_spec.rb
new file mode 100644
index 00000000000..f4fcec2fbc2
--- /dev/null
+++ b/spec/services/commits/commit_patch_service_spec.rb
@@ -0,0 +1,92 @@
+# frozen_string_literal: true
+require 'spec_helper'
+
+describe Commits::CommitPatchService do
+  describe '#execute' do
+    let(:patches) do
+      patches_folder = Rails.root.join('spec/fixtures/patchfiles')
+      content_1 = File.read(File.join(patches_folder, "0001-This-does-not-apply-to-the-feature-branch.patch"))
+      content_2 = File.read(File.join(patches_folder, "0001-A-commit-from-a-patch.patch"))
+
+      [content_1, content_2]
+    end
+    let(:user) { project.creator }
+    let(:branch_name) { 'branch-with-patches' }
+    let(:project) { create(:project, :repository) }
+    let(:start_branch) { nil }
+    let(:params) { { branch_name: branch_name, patches: patches, start_branch: start_branch } }
+
+    subject(:service) do
+      described_class.new(project, user, params)
+    end
+
+    it 'returns a successful result' do
+      result = service.execute
+
+      branch = project.repository.find_branch(branch_name)
+
+      expect(result[:status]).to eq(:success)
+      expect(result[:result]).to eq(branch.target)
+    end
+
+    it 'is based off HEAD when no start ref is passed' do
+      service.execute
+
+      merge_base = project.repository.merge_base(project.repository.root_ref, branch_name)
+
+      expect(merge_base).to eq(project.repository.commit('HEAD').sha)
+    end
+
+    context 'when specifying a different start branch' do
+      let(:start_branch) { 'with-codeowners' }
+
+      it 'is based of the correct branch' do
+        service.execute
+
+        merge_base = project.repository.merge_base(start_branch, branch_name)
+
+        expect(merge_base).to eq(project.repository.commit(start_branch).sha)
+      end
+    end
+
+    shared_examples 'an error response' do |expected_message|
+      it 'returns the correct error' do
+        result = service.execute
+
+        expect(result[:status]).to eq(:error)
+        expect(result[:message]).to match(expected_message)
+      end
+    end
+
+    context 'when the user does not have access' do
+      let(:user) { create(:user) }
+
+      it_behaves_like 'an error response',
+                      'You are not allowed to push into this branch'
+    end
+
+    context 'when the patches are not valid' do
+      let(:patches) { "a" * 2.1.megabytes }
+
+      it_behaves_like 'an error response', 'Patches are too big'
+    end
+
+    context 'when the new branch name is invalid' do
+      let(:branch_name) { 'HEAD' }
+
+      it_behaves_like 'an error response', 'Branch name is invalid'
+    end
+
+    context 'when the patches do not apply' do
+      let(:branch_name) { 'feature' }
+
+      it_behaves_like 'an error response', 'Patch failed at'
+    end
+
+    context 'when specifying a non existent start branch' do
+      let(:start_branch) { 'does-not-exist' }
+
+      it_behaves_like 'an error response', 'Invalid reference name'
+    end
+  end
+end
diff --git a/spec/services/merge_requests/build_service_spec.rb b/spec/services/merge_requests/build_service_spec.rb
index 9f1da7d9419..c9a668994eb 100644
--- a/spec/services/merge_requests/build_service_spec.rb
+++ b/spec/services/merge_requests/build_service_spec.rb
@@ -392,5 +392,13 @@ describe MergeRequests::BuildService do
         expect(merge_request.source_project).to eq(project)
       end
     end
+
+    context 'when specifying target branch in the description' do
+      let(:description) { "A merge request targeting another branch\n\n/target_branch with-codeowners" }
+
+      it 'sets the attribute from the quick actions' do
+        expect(merge_request.target_branch).to eq('with-codeowners')
+      end
+    end
   end
 end
diff --git a/spec/services/quick_actions/interpret_service_spec.rb b/spec/services/quick_actions/interpret_service_spec.rb
index e513ee7ae44..5a7cafcb60f 100644
--- a/spec/services/quick_actions/interpret_service_spec.rb
+++ b/spec/services/quick_actions/interpret_service_spec.rb
@@ -1213,6 +1213,15 @@ describe QuickActions::InterpretService do
         end
       end
     end
+
+    it 'limits to commands passed ' do
+      content = "/shrug\n/close"
+
+      text, commands = service.execute(content, issue, only: [:shrug])
+
+      expect(commands).to be_empty
+      expect(text).to eq("#{described_class::SHRUG}\n/close")
+    end
   end
 
   describe '#explain' do
diff --git a/spec/workers/email_receiver_worker_spec.rb b/spec/workers/email_receiver_worker_spec.rb
index e4e77c667b3..045135255d6 100644
--- a/spec/workers/email_receiver_worker_spec.rb
+++ b/spec/workers/email_receiver_worker_spec.rb
@@ -46,6 +46,21 @@ describe EmailReceiverWorker, :mailer do
           should_not_email_anyone
         end
       end
+
+      context 'when the error is Gitlab::Email::InvalidAttachment' do
+        let(:error) { Gitlab::Email::InvalidAttachment.new("Could not deal with that") }
+
+        it 'reports the error to the sender' do
+          perform_enqueued_jobs do
+            described_class.new.perform(raw_message)
+          end
+
+          email = ActionMailer::Base.deliveries.last
+          expect(email).not_to be_nil
+          expect(email.to).to eq(["jake@adventuretime.ooo"])
+          expect(email.body.parts.last.to_s).to include("Could not deal with that")
+        end
+      end
     end
   end