Validate new blocks during copy

It is possible that a block is copied prior to validation, in which case
some fields (like when) which should be something other than a string might
not be. Using validate() in copy() is relatively harmless and ensures the
blocks are in the proper structure.

This also cleans up some of the finalized logic from an earlier commit and
adds similar logic for validated.

Fixes #17018

lib/ansible/playbook/base.py

@@ -65,9 +65,6 @@ class Base:
     _ignore_errors       = FieldAttribute(isa='bool')
     _check_mode          = FieldAttribute(isa='bool')
 
-    # other internal params
-    _finalized           = False
-
     # param names which have been deprecated/removed
     DEPRECATED_ATTRIBUTES = [
         'sudo', 'sudo_user', 'sudo_pass', 'sudo_exe', 'sudo_flags',
@@ -81,9 +78,12 @@ class Base:
         self._loader = None
         self._variable_manager = None
 
+        # other internal params
+        self._validated = False
+        self._finalized = False
+
         # every object gets a random uuid:
         self._uuid = uuid.uuid4()
-        #self._uuid = 1
 
         # and initialize the base attributes
         self._initialize_base_attributes()
@@ -272,6 +272,7 @@ class Base:
     def validate(self, all_vars=dict()):
         ''' validation that is done at parse time, not load time '''
 
+        if not self._validated:
             # walk all fields in the object
             for (name, attribute) in iteritems(self._get_base_attributes()):
 
@@ -284,8 +285,12 @@ class Base:
                     value = getattr(self, name)
                     if value is not None:
                         if attribute.isa == 'string' and isinstance(value, (list, dict)):
-                        raise AnsibleParserError("The field '%s' is supposed to be a string type,"
+                            raise AnsibleParserError(
-                                " however the incoming data structure is a %s" % (name, type(value)), obj=self.get_ds())
+                                "The field '%s' is supposed to be a string type,"
+                                " however the incoming data structure is a %s" % (name, type(value)), obj=self.get_ds()
+                            )
+
+        self._validated = True
 
     def copy(self):
         '''
@@ -305,7 +310,8 @@ class Base:
 
         new_me._loader = self._loader
         new_me._variable_manager = self._variable_manager
-
+        new_me._validated = self._validated
+        new_me._finalized = self._finalized
         new_me._uuid = self._uuid
 
         # if the ds value was set on the object, copy it to the new copy too

lib/ansible/playbook/block.py

@@ -192,6 +192,7 @@ class Block(Base, Become, Conditional, Taggable):
         if self._role:
             new_me._role = self._role
 
+        new_me.validate()
         return new_me
 
     def serialize(self):