Define the default value for only/except policies

Currently, if a job does not have only/except policies, the policy is considered as an unspecified state, and therefore the job is executed regardless of how it's executed and which branch/tags are targetted.
Ideally, this should be specified as only: ['branches', 'tags'], as it indicates that unspecified policy jobs are meant to run on any git references.

4 files changed, 48 insertions, 6 deletions

diff --git a/lib/gitlab/ci/config/entry/except_policy.rb b/lib/gitlab/ci/config/entry/except_policy.rb
new file mode 100644
index 00000000000..46ded35325d
--- /dev/null
+++ b/lib/gitlab/ci/config/entry/except_policy.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module Ci
+    class Config
+      module Entry
+        ##
+        # Entry that represents an only/except trigger policy for the job.
+        #
+        class ExceptPolicy < Policy
+          def self.default
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/ci/config/entry/job.rb b/lib/gitlab/ci/config/entry/job.rb
index 4f2ac94b6c3..085be5da08d 100644
--- a/lib/gitlab/ci/config/entry/job.rb
+++ b/lib/gitlab/ci/config/entry/job.rb
@@ -65,10 +65,10 @@ module Gitlab
           entry :services, Entry::Services,
             description: 'Services that will be used to execute this job.'
 
-          entry :only, Entry::Policy,
+          entry :only, Entry::OnlyPolicy,
             description: 'Refs policy this job will be executed for.'
 
-          entry :except, Entry::Policy,
+          entry :except, Entry::ExceptPolicy,
             description: 'Refs policy this job will be executed for.'
 
           entry :variables, Entry::Variables,
diff --git a/lib/gitlab/ci/config/entry/only_policy.rb b/lib/gitlab/ci/config/entry/only_policy.rb
new file mode 100644
index 00000000000..9a581b8e97e
--- /dev/null
+++ b/lib/gitlab/ci/config/entry/only_policy.rb
@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module Ci
+    class Config
+      module Entry
+        ##
+        # Entry that represents an only/except trigger policy for the job.
+        #
+        class OnlyPolicy < Policy
+          def self.default
+            { refs: %w[branches tags] }
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/ci/config/entry/policy.rb b/lib/gitlab/ci/config/entry/policy.rb
index 998da1f6837..81e74a639fc 100644
--- a/lib/gitlab/ci/config/entry/policy.rb
+++ b/lib/gitlab/ci/config/entry/policy.rb
@@ -5,12 +5,9 @@ module Gitlab
     class Config
       module Entry
         ##
-        # Entry that represents an only/except trigger policy for the job.
+        # Base class for OnlyPolicy and ExceptPolicy
         #
         class Policy < ::Gitlab::Config::Entry::Simplifiable
-          strategy :RefsPolicy, if: -> (config) { config.is_a?(Array) }
-          strategy :ComplexPolicy, if: -> (config) { config.is_a?(Hash) }
-
           class RefsPolicy < ::Gitlab::Config::Entry::Node
             include ::Gitlab::Config::Entry::Validatable
 
@@ -66,6 +63,16 @@ module Gitlab
 
           def self.default
           end
+
+          ##
+          # Class-level execution won't be inherited by subclasses by default.
+          # Therefore, we need to explicitly execute that for OnlyPolicy and ExceptPolicy
+          def self.inherited(klass)
+            super
+
+            klass.strategy :RefsPolicy, if: -> (config) { config.is_a?(Array) }
+            klass.strategy :ComplexPolicy, if: -> (config) { config.is_a?(Hash) }
+          end
         end
       end
     end