Add array support for labels

* Support label parameter as comma separated and array of strings
for merge requests and issues api endpoints

3 files changed, 28 insertions, 4 deletions

diff --git a/lib/api/issues.rb b/lib/api/issues.rb
index f43f4d961d6..d59d2f5a098 100644
--- a/lib/api/issues.rb
+++ b/lib/api/issues.rb
@@ -34,7 +34,7 @@ module API
       # rubocop: enable CodeReuse/ActiveRecord
 
       params :issues_params do
-        optional :labels, type: String, desc: 'Comma-separated list of label names'
+        optional :labels, type: Array[String], coerce_with: Validations::Types::LabelsList.coerce, desc: 'Comma-separated list of label names'
         optional :milestone, type: String, desc: 'Milestone title'
         optional :order_by, type: String, values: %w[created_at updated_at], default: 'created_at',
                             desc: 'Return issues ordered by `created_at` or `updated_at` fields.'
@@ -65,7 +65,7 @@ module API
         optional :assignee_ids, type: Array[Integer], desc: 'The array of user IDs to assign issue'
         optional :assignee_id,  type: Integer, desc: '[Deprecated] The ID of a user to assign issue'
         optional :milestone_id, type: Integer, desc: 'The ID of a milestone to assign issue'
-        optional :labels, type: String, desc: 'Comma-separated list of label names'
+        optional :labels, type: Array[String], coerce_with: Validations::Types::LabelsList.coerce, desc: 'Comma-separated list of label names'
         optional :due_date, type: String, desc: 'Date string in the format YEAR-MONTH-DAY'
         optional :confidential, type: Boolean, desc: 'Boolean parameter if the issue should be confidential'
         optional :discussion_locked, type: Boolean, desc: " Boolean parameter indicating if the issue's discussion is locked"
diff --git a/lib/api/merge_requests.rb b/lib/api/merge_requests.rb
index 2e794076a43..b2a2aa8837d 100644
--- a/lib/api/merge_requests.rb
+++ b/lib/api/merge_requests.rb
@@ -95,7 +95,7 @@ module API
         optional :sort, type: String, values: %w[asc desc], default: 'desc',
                         desc: 'Return merge requests sorted in `asc` or `desc` order.'
         optional :milestone, type: String, desc: 'Return merge requests for a specific milestone'
-        optional :labels, type: String, desc: 'Comma-separated list of label names'
+        optional :labels, type: Array[String], coerce_with: Validations::Types::LabelsList.coerce, desc: 'Comma-separated list of label names'
         optional :created_after, type: DateTime, desc: 'Return merge requests created after the specified time'
         optional :created_before, type: DateTime, desc: 'Return merge requests created before the specified time'
         optional :updated_after, type: DateTime, desc: 'Return merge requests updated after the specified time'
@@ -179,7 +179,7 @@ module API
           optional :description, type: String, desc: 'The description of the merge request'
           optional :assignee_id, type: Integer, desc: 'The ID of a user to assign the merge request'
           optional :milestone_id, type: Integer, desc: 'The ID of a milestone to assign the merge request'
-          optional :labels, type: String, coerce_with: ->(val) { val.is_a?(Array) ? val.join(', ') : val }, desc: 'Comma-separated list of label names'
+          optional :labels, type: Array[String], coerce_with: Validations::Types::LabelsList.coerce, desc: 'Comma-separated list of label names'
           optional :remove_source_branch, type: Boolean, desc: 'Remove source branch when merging'
           optional :allow_collaboration, type: Boolean, desc: 'Allow commits from members who can merge to the target branch'
           optional :allow_maintainer_to_push, type: Boolean, as: :allow_collaboration, desc: '[deprecated] See allow_collaboration'
diff --git a/lib/api/validations/types/labels_list.rb b/lib/api/validations/types/labels_list.rb
new file mode 100644
index 00000000000..47cd83c29cf
--- /dev/null
+++ b/lib/api/validations/types/labels_list.rb
@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+module API
+  module Validations
+    module Types
+      class LabelsList
+        def self.coerce
+          lambda do |value|
+            case value
+            when String
+              value.split(',').map(&:strip)
+            when Array
+              value.map { |v| v.to_s.split(',').map(&:strip) }.flatten
+            when LabelsList
+              value
+            else
+              []
+            end
+          end
+        end
+      end
+    end
+  end
+end