Flatten Entry::Commands elements

Flattens Entry::Commands elements so we can use YAML anchors as part of
the script definition.

lib/gitlab/ci/config/entry/commands.rb

@@ -11,11 +11,11 @@ module Gitlab
           include ::Gitlab::Config::Entry::Validatable
 
           validations do
-            validates :config, array_of_strings_or_string: true
+            validates :config, array_of_strings_or_arrays_of_strings: true
           end
 
           def value
-            Array(@config)
+            Array(@config).flatten
           end
         end
       end

lib/gitlab/config/entry/validators.rb

@@ -206,6 +206,16 @@ module Gitlab
           end
         end
 
+        class ArrayOfStringsOrArraysOfStringsValidator < ActiveModel::EachValidator
+          include LegacyValidationHelpers
+
+          def validate_each(record, attribute, value)
+            unless value.is_a?(Array) && value.all? { |element| element.is_a?(String) || validate_array_of_strings(element) }
+              record.errors.add(attribute, 'should be an array of strings and arrays of strings')
+            end
+          end
+        end
+
         class ArrayOfStringsOrRegexpsWithFallbackValidator < ArrayOfStringsOrRegexpsValidator
           protected
 

spec/lib/gitlab/ci/config/entry/commands_spec.rb

@@ -5,7 +5,7 @@ require 'spec_helper'
 describe Gitlab::Ci::Config::Entry::Commands do
   let(:entry) { described_class.new(config) }
 
-  context 'when entry config value is an array' do
+  context 'when entry config value is an array of strings' do
     let(:config) { %w(ls pwd) }
 
     describe '#value' do
@@ -37,13 +37,57 @@ describe Gitlab::Ci::Config::Entry::Commands do
     end
   end
 
+  context 'when entry config value is array of arrays of strings' do
+    let(:config) { [['ls'], ['pwd', 'echo 1']] }
+
+    describe '#value' do
+      it 'returns array of strings' do
+        expect(entry.value).to eq ['ls', 'pwd', 'echo 1']
+      end
+    end
+
+    describe '#errors' do
+      it 'does not append errors' do
+        expect(entry.errors).to be_empty
+      end
+    end
+
+    describe '#valid?' do
+      it 'is valid' do
+        expect(entry).to be_valid
+      end
+    end
+  end
+
+  context 'when entry config value is array of strings and arrays of strings' do
+    let(:config) { ['ls', ['pwd', 'echo 1']] }
+
+    describe '#value' do
+      it 'returns array of strings' do
+        expect(entry.value).to eq ['ls', 'pwd', 'echo 1']
+      end
+    end
+
+    describe '#errors' do
+      it 'does not append errors' do
+        expect(entry.errors).to be_empty
+      end
+    end
+
+    describe '#valid?' do
+      it 'is valid' do
+        expect(entry).to be_valid
+      end
+    end
+  end
+
   context 'when entry value is not valid' do
     let(:config) { 1 }
 
     describe '#errors' do
       it 'saves errors' do
         expect(entry.errors)
-          .to include 'commands config should be an array of strings or a string'
+          .to include 'commands config should be an array of strings and arrays of strings'
       end
     end
   end

spec/lib/gitlab/ci/yaml_processor_spec.rb

@@ -363,6 +363,7 @@ module Gitlab
         end
 
         describe "script" do
+          context 'when script is array of strings' do
             let(:config) do
               {
                 test: { script: ["script"] }
@@ -374,6 +375,19 @@ module Gitlab
             end
           end
 
+          context 'when script is array of arrays of strings' do
+            let(:config) do
+              {
+                test: { script: [["script"], ["echo 1"], "ls"] }
+              }
+            end
+
+            it "return commands with scripts concencaced" do
+              expect(subject[:options][:script]).to eq(["script", "echo 1", "ls"])
+            end
+          end
+        end
+
         describe "after_script" do
           context "in global context" do
             let(:config) do