Address review comments

app/services/slash_commands/interpret_service.rb

@@ -92,18 +92,11 @@ module SlashCommands
 
     desc 'Assign'
     explanation do |users|
-      if issuable.is_a?(Issue)
-        "Assigns #{users.map(&:to_reference).to_sentence}." if users.any?
-      else
-        "Assigns #{users.last.to_reference}." if users.any?
-      end
+      users = issuable.is_a?(Issue) ? users : users.take(1)
+      "Assigns #{users.map(&:to_reference).to_sentence}."
     end
     params do
-      if issuable.is_a?(Issue)
-        ['@user1 @user2']
-      else
-        ['@user']
-      end
+      issuable.is_a?(Issue) ? '@user1 @user2' : '@user'
     end
     condition do
       current_user.can?(:"admin_#{issuable.to_ability_name}", project)
@@ -122,17 +115,19 @@ module SlashCommands
       end
     end
 
-    desc 'Remove all or specific assignee(s)'
-    explanation do
-      'Removes assignee(s)'
-    end
-    params do
+    desc do
       if issuable.is_a?(Issue)
-        ['@user1 @user2']
+        'Remove all or specific assignee(s)'
       else
-        []
+        'Remove assignee'
       end
     end
+    explanation do
+      "Removes #{'assignee'.pluralize(issuable.assignees.size)} #{issuable.assignees.map(&:to_reference).to_sentence}"
+    end
+    params do
+      issuable.is_a?(Issue) ? '@user1 @user2' : ''
+    end
     condition do
       issuable.persisted? &&
         issuable.assignees.any? &&
@@ -142,11 +137,12 @@ module SlashCommands
       users = extract_users(unassign_param)
 
       if issuable.is_a?(Issue)
-        if users.any?
-          @updates[:assignee_ids] = issuable.assignees.pluck(:id) - users.map(&:id)
-        else
-          @updates[:assignee_ids] = []
-        end
+        @updates[:assignee_ids] =
+          if users.any?
+            issuable.assignees.pluck(:id) - users.map(&:id)
+          else
+            []
+          end
       else
         @updates[:assignee_id] = nil
       end

doc/user/project/slash_commands.md

@@ -16,8 +16,9 @@ do.
 | `/reopen`                  | Reopen the issue or merge request |
 | `/merge`                   | Merge (when pipeline succeeds) |
 | `/title <New title>`       | Change title |
-| `/assign @username`        | Assign |
-| `/unassign @user1 @user2`  | Remove all the assignees or specified ones |
+| `/assign @user1 @user2 `   | Add assignee(s) |
+| `/reassign @user1 @user2 ` | Change assignee(s) |
+| `/unassign @user1 @user2`  | Remove all or specific assignee(s) |
 | `/milestone %milestone`    | Set milestone |
 | `/remove_milestone`        | Remove milestone |
 | `/label ~foo ~"bar baz"`   | Add label(s) |
@@ -39,3 +40,6 @@ do.
 | `/weight <1-9>` | Set the weight of the issue |
 | `/clear_weight` | Clears the issue weight |
 | `/board_move ~column`      | Move issue to column on the board |
+
+Note: In GitLab EES every issue can have more than one assignee, so commands `/assign`, `/unassign` and `/reassign`
+support multiple assignees.

lib/gitlab/slash_commands/command_definition.rb

@@ -57,7 +57,7 @@ module Gitlab
 
         prms = params
         if prms.respond_to?(:call)
-          prms = context.instance_exec(&prms) rescue ''
+          prms = Array(context.instance_exec(&prms)) rescue params
         end
 
         {

spec/services/slash_commands/interpret_service_spec.rb

@@ -947,7 +947,7 @@ describe SlashCommands::InterpretService, services: true do
       it 'includes current assignee reference' do
         _, explanations = service.explain(content, issue)
 
-        expect(explanations).to eq(['Removes assignee(s)'])
+        expect(explanations).to eq(["Removes assignee #{developer.to_reference}"])
       end
     end