No longer persist XModule templates

Instead, we use XModule field default values when creating an empty
XModule. Driven by this use case, we also allow for XModules to be
created in memory without being persisted to the database at all. This
necessitates a change to the Modulestore api, replacing clone_item with
create_draft and save_xmodule.

CHANGELOG.rst

@@ -43,6 +43,13 @@ history of background tasks for a given problem and student.
 Blades: Small UX fix on capa multiple-choice problems.  Make labels only
 as wide as the text to reduce accidental choice selections.
 
+Studio: 
+- use xblock field defaults to initialize all new instances' fields and
+only use templates as override samples.
+- create new instances via in memory create_xmodule and related methods rather
+than cloning a db record.
+- have an explicit method for making a draft copy as distinct from making a new module.
+
 Studio: Remove XML from the video component editor. All settings are
 moved to be edited as metadata.
 

README.md

@@ -239,7 +239,6 @@ CMS templates. Fortunately, `rake` will do all of this for you! Just run:
 
     $ rake django-admin[syncdb]
     $ rake django-admin[migrate]
-    $ rake cms:update_templates
 
 If you are running these commands using the [`zsh`](http://www.zsh.org/) shell,
 zsh will assume that you are doing

cms/djangoapps/contentstore/course_info_model.py

@@ -20,8 +20,8 @@ def get_course_updates(location):
     try:
         course_updates = modulestore('direct').get_item(location)
     except ItemNotFoundError:
-        template = Location(['i4x', 'edx', "templates", 'course_info', "Empty"])
-        course_updates = modulestore('direct').clone_item(template, Location(location))
+        modulestore('direct').create_and_save_xmodule(location)
+        course_updates = modulestore('direct').get_item(location)
 
     # current db rep: {"_id" : locationjson, "definition" : { "data" : "<ol>[<li><h2>date</h2>content</li>]</ol>"} "metadata" : ignored}
     location_base = course_updates.location.url()

cms/djangoapps/contentstore/features/common.py

@@ -208,7 +208,7 @@ def set_date_and_time(date_css, desired_date, time_css, desired_time):
 def i_created_a_video_component(step):
     world.create_component_instance(
         step, '.large-video-icon',
-        'i4x://edx/templates/video/default',
+        'video',
         '.xmodule_VideoModule'
     )
 

cms/djangoapps/contentstore/features/component_settings_editor_helpers.py

@@ -7,9 +7,9 @@
 
 
 @world.absorb
-def create_component_instance(step, component_button_css, instance_id, expected_css):
+def create_component_instance(step, component_button_css, category, expected_css, boilerplate=None):
     click_new_component_button(step, component_button_css)
-    click_component_from_menu(instance_id, expected_css)
+    click_component_from_menu(category, boilerplate, expected_css)
 
 
 @world.absorb
@@ -19,19 +19,21 @@ def click_new_component_button(step, component_button_css):
 
 
 @world.absorb
-def click_component_from_menu(instance_id, expected_css):
+def click_component_from_menu(category, boilerplate, expected_css):
     """
     Creates a component from `instance_id`. For components with more
     than one template, clicks on `elem_css` to create the new
     component. Components with only one template are created as soon
     as the user clicks the appropriate button, so we assert that the
     expected component is present.
     """
-    elem_css = "a[data-location='%s']" % instance_id
+    if boilerplate:
+        elem_css = "a[data-category='{}'][data-boilerplate='{}']".format(category, boilerplate)
+    else:
+        elem_css = "a[data-category='{}']:not([data-boilerplate])".format(category)
     elements = world.css_find(elem_css)
-    assert(len(elements) == 1)
-    if elements[0]['id'] == instance_id:  # If this is a component with multiple templates
-        world.css_click(elem_css)
+    assert_equal(len(elements), 1)
+    world.css_click(elem_css)
     assert_equal(1, len(world.css_find(expected_css)))
 
 

cms/djangoapps/contentstore/features/discussion-editor.py

@@ -8,7 +8,7 @@
 def i_created_discussion_tag(step):
     world.create_component_instance(
         step, '.large-discussion-icon',
-        'i4x://edx/templates/discussion/Discussion_Tag',
+        'discussion',
         '.xmodule_DiscussionModule'
     )
 
@@ -26,5 +26,5 @@ def i_see_only_the_settings_and_values(step):
 @step('creating a discussion takes a single click')
 def discussion_takes_a_single_click(step):
     assert(not world.is_css_present('.xmodule_DiscussionModule'))
-    world.css_click("a[data-location='i4x://edx/templates/discussion/Discussion_Tag']")
+    world.css_click("a[data-category='discussion']")
     assert(world.is_css_present('.xmodule_DiscussionModule'))

cms/djangoapps/contentstore/features/html-editor.py

@@ -7,7 +7,7 @@
 @step('I have created a Blank HTML Page$')
 def i_created_blank_html_page(step):
     world.create_component_instance(
-        step, '.large-html-icon', 'i4x://edx/templates/html/Blank_HTML_Page',
+        step, '.large-html-icon', 'html',
         '.xmodule_HtmlModule'
     )
 

cms/djangoapps/contentstore/features/problem-editor.py

@@ -158,7 +158,7 @@ def create_latex_problem(step):
     world.click_new_component_button(step, '.large-problem-icon')
     # Go to advanced tab.
     world.css_click('#ui-id-2')
-    world.click_component_from_menu("i4x://edx/templates/problem/Problem_Written_in_LaTeX", '.xmodule_CapaModule')
+    world.click_component_from_menu("problem", "latex_problem.yaml", '.xmodule_CapaModule')
 
 
 @step('I edit and compile the High Level Source')

cms/djangoapps/contentstore/features/studio-overview-togglesection.py

@@ -22,7 +22,7 @@ def have_a_course_with_1_section(step):
     section = world.ItemFactory.create(parent_location=course.location)
     subsection1 = world.ItemFactory.create(
         parent_location=section.location,
-        template='i4x://edx/templates/sequential/Empty',
+        category='sequential',
         display_name='Subsection One',)
 
 
@@ -33,18 +33,18 @@ def have_a_course_with_two_sections(step):
     section = world.ItemFactory.create(parent_location=course.location)
     subsection1 = world.ItemFactory.create(
         parent_location=section.location,
-        template='i4x://edx/templates/sequential/Empty',
+        category='sequential',
         display_name='Subsection One',)
     section2 = world.ItemFactory.create(
         parent_location=course.location,
         display_name='Section Two',)
     subsection2 = world.ItemFactory.create(
         parent_location=section2.location,
-        template='i4x://edx/templates/sequential/Empty',
+        category='sequential',
         display_name='Subsection Alpha',)
     subsection3 = world.ItemFactory.create(
         parent_location=section2.location,
-        template='i4x://edx/templates/sequential/Empty',
+        category='sequential',
         display_name='Subsection Beta',)
 
 

cms/djangoapps/contentstore/features/video.py

@@ -14,7 +14,7 @@ def does_not_autoplay(_step):
 @step('creating a video takes a single click')
 def video_takes_a_single_click(_step):
     assert(not world.is_css_present('.xmodule_VideoModule'))
-    world.css_click("a[data-location='i4x://edx/templates/video/default']")
+    world.css_click("a[data-category='video']")
     assert(world.is_css_present('.xmodule_VideoModule'))
 
 

cms/djangoapps/contentstore/module_info_model.py

@@ -3,13 +3,13 @@
 from xmodule.modulestore import Location
 
 
-def get_module_info(store, location, parent_location=None, rewrite_static_links=False):
+def get_module_info(store, location, rewrite_static_links=False):
     try:
         module = store.get_item(location)
     except ItemNotFoundError:
         # create a new one
-        template_location = Location(['i4x', 'edx', 'templates', location.category, 'Empty'])
-        module = store.clone_item(template_location, location)
+        store.create_and_save_xmodule(location)
+        module = store.get_item(location)
 
     data = module.data
     if rewrite_static_links:
@@ -29,22 +29,20 @@ def get_module_info(store, location, parent_location=None, rewrite_static_links=
         'id': module.location.url(),
         'data': data,
         # TODO (cpennington): This really shouldn't have to do this much reaching in to get the metadata
-        'metadata': module._model_data._kvs._metadata
+        # what's the intent here? all metadata incl inherited & namespaced?
+        'metadata': module.xblock_kvs._metadata
     }
 
 
 def set_module_info(store, location, post_data):
     module = None
     try:
         module = store.get_item(location)
-    except:
-        pass
-
-    if module is None:
-        # new module at this location
-        # presume that we have an 'Empty' template
-        template_location = Location(['i4x', 'edx', 'templates', location.category, 'Empty'])
-        module = store.clone_item(template_location, location)
+    except ItemNotFoundError:
+        # new module at this location: almost always used for the course about pages; thus, no parent. (there
+        # are quite a handful of about page types available for a course and only the overview is pre-created)
+        store.create_and_save_xmodule(location)
+        module = store.get_item(location)
 
     if post_data.get('data') is not None:
         data = post_data['data']
@@ -79,4 +77,4 @@ def set_module_info(store, location, post_data):
 
         # commit to datastore
         # TODO (cpennington): This really shouldn't have to do this much reaching in to get the metadata
-        store.update_metadata(location, module._model_data._kvs._metadata)
+        store.update_metadata(location, module.xblock_kvs._metadata)