Add params validations and remove extra params support

Remove label_name and milestone_title params support
Add mutually_exclusive validation for author_id and author_username
Add mutually_exclusive validation for assignee_id and assignee_username
Add validation to allow single value for asignee_username on CE
Add separate issue_stats_params helper for statistics params and
reuse in issues_params.

1 files changed, 36 insertions, 0 deletions

diff --git a/lib/api/validations/check_assignees_count.rb b/lib/api/validations/check_assignees_count.rb
new file mode 100644
index 00000000000..e19c88e97b1
--- /dev/null
+++ b/lib/api/validations/check_assignees_count.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+module API
+  module Validations
+    class CheckAssigneesCount < Grape::Validations::Base
+      def self.coerce
+        lambda do |value|
+          case value
+          when String
+            [value]
+          when Array
+            value
+          when CheckAssigneesCount
+            value
+          else
+            []
+          end
+        end
+      end
+
+      def validate_param!(attr_name, params)
+        unless param_allowed?(attr_name, params)
+          raise Grape::Exceptions::Validation,
+                params: [@scope.full_name(attr_name)],
+                message: "allows one value, but found #{params[attr_name].size}: #{params[attr_name].join(", ")}"
+        end
+      end
+
+      private
+
+      def param_allowed?(attr_name, params)
+        params[attr_name].size <= 1
+      end
+    end
+  end
+end