Merge branch '4273-slash-commands' into 'master'test-8-11-stable-2

Support slash commands in issues / MR description & comments

See merge request !5021

4 files changed, 278 insertions, 0 deletions

diff --git a/lib/gitlab/email/handler/base_handler.rb b/lib/gitlab/email/handler/base_handler.rb
index b7ed11cb638..7cccf465334 100644
--- a/lib/gitlab/email/handler/base_handler.rb
+++ b/lib/gitlab/email/handler/base_handler.rb
@@ -45,6 +45,7 @@ module Gitlab
 
         def verify_record!(record:, invalid_exception:, record_name:)
           return if record.persisted?
+          return if record.errors.key?(:commands_only)
 
           error_title = "The #{record_name} could not be created for the following reasons:"
 
diff --git a/lib/gitlab/slash_commands/command_definition.rb b/lib/gitlab/slash_commands/command_definition.rb
new file mode 100644
index 00000000000..60d35be2599
--- /dev/null
+++ b/lib/gitlab/slash_commands/command_definition.rb
@@ -0,0 +1,57 @@
+module Gitlab
+  module SlashCommands
+    class CommandDefinition
+      attr_accessor :name, :aliases, :description, :params, :condition_block, :action_block
+
+      def initialize(name, attributes = {})
+        @name = name
+
+        @aliases         = attributes[:aliases] || []
+        @description     = attributes[:description] || ''
+        @params          = attributes[:params] || []
+        @condition_block = attributes[:condition_block]
+        @action_block    = attributes[:action_block]
+      end
+
+      def all_names
+        [name, *aliases]
+      end
+
+      def noop?
+        action_block.nil?
+      end
+
+      def available?(opts)
+        return true unless condition_block
+
+        context = OpenStruct.new(opts)
+        context.instance_exec(&condition_block)
+      end
+
+      def execute(context, opts, arg)
+        return if noop? || !available?(opts)
+
+        if arg.present?
+          context.instance_exec(arg, &action_block)
+        elsif action_block.arity == 0
+          context.instance_exec(&action_block)
+        end
+      end
+
+      def to_h(opts)
+        desc = description
+        if desc.respond_to?(:call)
+          context = OpenStruct.new(opts)
+          desc = context.instance_exec(&desc) rescue ''
+        end
+
+        {
+          name: name,
+          aliases: aliases,
+          description: desc,
+          params: params
+        }
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/slash_commands/dsl.rb b/lib/gitlab/slash_commands/dsl.rb
new file mode 100644
index 00000000000..50b0937d267
--- /dev/null
+++ b/lib/gitlab/slash_commands/dsl.rb
@@ -0,0 +1,98 @@
+module Gitlab
+  module SlashCommands
+    module Dsl
+      extend ActiveSupport::Concern
+
+      included do
+        cattr_accessor :command_definitions, instance_accessor: false do
+          []
+        end
+
+        cattr_accessor :command_definitions_by_name, instance_accessor: false do
+          {}
+        end
+      end
+
+      class_methods do
+        # Allows to give a description to the next slash command.
+        # This description is shown in the autocomplete menu.
+        # It accepts a block that will be evaluated with the context given to
+        # `CommandDefintion#to_h`.
+        #
+        # Example:
+        #
+        #   desc do
+        #     "This is a dynamic description for #{noteable.to_ability_name}"
+        #   end
+        #   command :command_key do |arguments|
+        #     # Awesome code block
+        #   end
+        def desc(text = '', &block)
+          @description = block_given? ? block : text
+        end
+
+        # Allows to define params for the next slash command.
+        # These params are shown in the autocomplete menu.
+        #
+        # Example:
+        #
+        #   params "~label ~label2"
+        #   command :command_key do |arguments|
+        #     # Awesome code block
+        #   end
+        def params(*params)
+          @params = params
+        end
+
+        # Allows to define conditions that must be met in order for the command
+        # to be returned by `.command_names` & `.command_definitions`.
+        # It accepts a block that will be evaluated with the context given to
+        # `CommandDefintion#to_h`.
+        #
+        # Example:
+        #
+        #   condition do
+        #     project.public?
+        #   end
+        #   command :command_key do |arguments|
+        #     # Awesome code block
+        #   end
+        def condition(&block)
+          @condition_block = block
+        end
+
+        # Registers a new command which is recognizeable from body of email or
+        # comment.
+        # It accepts aliases and takes a block.
+        #
+        # Example:
+        #
+        #   command :my_command, :alias_for_my_command do |arguments|
+        #     # Awesome code block
+        #   end
+        def command(*command_names, &block)
+          name, *aliases = command_names
+
+          definition = CommandDefinition.new(
+            name,
+            aliases:          aliases,
+            description:      @description,
+            params:           @params,
+            condition_block:  @condition_block,
+            action_block:     block
+          )
+
+          self.command_definitions << definition
+
+          definition.all_names.each do |name|
+            self.command_definitions_by_name[name] = definition
+          end
+
+          @description = nil
+          @params = nil
+          @condition_block = nil
+        end
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/slash_commands/extractor.rb b/lib/gitlab/slash_commands/extractor.rb
new file mode 100644
index 00000000000..a672e5e4855
--- /dev/null
+++ b/lib/gitlab/slash_commands/extractor.rb
@@ -0,0 +1,122 @@
+module Gitlab
+  module SlashCommands
+    # This class takes an array of commands that should be extracted from a
+    # given text.
+    #
+    # ```
+    # extractor = Gitlab::SlashCommands::Extractor.new([:open, :assign, :labels])
+    # ```
+    class Extractor
+      attr_reader :command_definitions
+
+      def initialize(command_definitions)
+        @command_definitions = command_definitions
+      end
+
+      # Extracts commands from content and return an array of commands.
+      # The array looks like the following:
+      # [
+      #   ['command1'],
+      #   ['command3', 'arg1 arg2'],
+      # ]
+      # The command and the arguments are stripped.
+      # The original command text is removed from the given `content`.
+      #
+      # Usage:
+      # ```
+      # extractor = Gitlab::SlashCommands::Extractor.new([:open, :assign, :labels])
+      # msg = %(hello\n/labels ~foo ~"bar baz"\nworld)
+      # commands = extractor.extract_commands(msg) #=> [['labels', '~foo ~"bar baz"']]
+      # msg #=> "hello\nworld"
+      # ```
+      def extract_commands(content, opts = {})
+        return [content, []] unless content
+
+        content = content.dup
+
+        commands = []
+
+        content.delete!("\r")
+        content.gsub!(commands_regex(opts)) do
+          if $~[:cmd]
+            commands << [$~[:cmd], $~[:arg]].reject(&:blank?)
+            ''
+          else
+            $~[0]
+          end
+        end
+
+        [content.strip, commands]
+      end
+
+      private
+
+      # Builds a regular expression to match known commands.
+      # First match group captures the command name and
+      # second match group captures its arguments.
+      #
+      # It looks something like:
+      #
+      #   /^\/(?<cmd>close|reopen|...)(?:( |$))(?<arg>[^\/\n]*)(?:\n|$)/
+      def commands_regex(opts)
+        names = command_names(opts).map(&:to_s)
+
+        @commands_regex ||= %r{
+            (?<code>
+              # Code blocks:
+              # ```
+              # Anything, including `/cmd arg` which are ignored by this filter
+              # ```
+
+              ^```
+              .+?
+              \n```$
+            )
+          |
+            (?<html>
+              # HTML block:
+              # <tag>
+              # Anything, including `/cmd arg` which are ignored by this filter
+              # </tag>
+
+              ^<[^>]+?>\n
+              .+?
+              \n<\/[^>]+?>$
+            )
+          |
+            (?<html>
+              # Quote block:
+              # >>>
+              # Anything, including `/cmd arg` which are ignored by this filter
+              # >>>
+
+              ^>>>
+              .+?
+              \n>>>$
+            )
+          |
+            (?:
+              # Command not in a blockquote, blockcode, or HTML tag:
+              # /close
+
+              ^\/
+              (?<cmd>#{Regexp.union(names)})
+              (?:
+                [ ]
+                (?<arg>[^\/\n]*)
+              )?
+              (?:\n|$)
+            )
+        }mx
+      end
+
+      def command_names(opts)
+        command_definitions.flat_map do |command|
+          next if command.noop?
+
+          command.all_names
+        end.compact
+      end
+    end
+  end
+end