Problem type filtering on `update_children` event

common/lib/xmodule/xmodule/capa_module.py

@@ -2,10 +2,12 @@
 import json
 import logging
 import sys
+from lxml import etree
 
 from pkg_resources import resource_string
 
 from .capa_base import CapaMixin, CapaFields, ComplexEncoder
+from capa import inputtypes
 from .progress import Progress
 from xmodule.x_module import XModule, module_attr
 from xmodule.raw_module import RawDescriptor
@@ -172,6 +174,13 @@ class CapaDescriptor(CapaFields, RawDescriptor):
         ])
         return non_editable_fields
 
+    @property
+    def problem_types(self):
+        """ Low-level problem type introspection for content libraries filtering by problem type """
+        tree = etree.XML(self.data)
+        registered_tas = inputtypes.registry.registered_tags()
+        return set([node.tag for node in tree.iter() if node.tag in registered_tas])
+
     # Proxy to CapaModule for access to any of its attributes
     answer_available = module_attr('answer_available')
     check_button_name = module_attr('check_button_name')

common/lib/xmodule/xmodule/library_content_module.py

@@ -222,23 +222,6 @@ class LibraryContentModule(LibraryContentFields, XModule, StudioEditableModule):
     as children of this block, but only a subset of those children are shown to
     any particular student.
     """
-    def _filter_children(self, child_locator):
-        """
-        Filters children by CAPA problem type, if configured
-        """
-        if self.capa_type == ANY_CAPA_TYPE_VALUE:
-            return True
-
-        if child_locator.block_type != CAPA_BLOCK_TYPE:
-            return False
-
-        block = self.runtime.get_block(child_locator)
-
-        if not hasattr(block, 'lcp'):
-            return True
-
-        return any(self.capa_type in capa_input.tags for capa_input in block.lcp.inputs.values())
-
     def selected_children(self):
         """
         Returns a set() of block_ids indicating which of the possible children
@@ -255,7 +238,7 @@ class LibraryContentModule(LibraryContentFields, XModule, StudioEditableModule):
             return self._selected_set  # pylint: disable=access-member-before-definition
         # Determine which of our children we will show:
         selected = set(tuple(k) for k in self.selected)  # set of (block_type, block_id) tuples
-        valid_block_keys = set([(c.block_type, c.block_id) for c in self.children if self._filter_children(c)])  # pylint: disable=no-member
+        valid_block_keys = set([(c.block_type, c.block_id) for c in self.children])  # pylint: disable=no-member
         # Remove any selected blocks that are no longer valid:
         selected -= (selected - valid_block_keys)
         # If max_count has been decreased, we may have to drop some previously selected blocks:

common/lib/xmodule/xmodule/library_tools.py

@@ -5,8 +5,9 @@ import hashlib
 from django.core.exceptions import PermissionDenied
 from opaque_keys.edx.locator import LibraryLocator
 from xblock.fields import Scope
-from xmodule.library_content_module import LibraryVersionReference
+from xmodule.library_content_module import LibraryVersionReference, ANY_CAPA_TYPE_VALUE
 from xmodule.modulestore.exceptions import ItemNotFoundError
+from xmodule.capa_module import CapaDescriptor
 
 
 class LibraryToolsService(object):
@@ -45,6 +46,18 @@ class LibraryToolsService(object):
             return library.location.library_key.version_guid
         return None
 
+    def _filter_child(self, dest_block, child_descriptor):
+        """
+        Filters children by CAPA problem type, if configured
+        """
+        if dest_block.capa_type == ANY_CAPA_TYPE_VALUE:
+            return True
+
+        if not isinstance(child_descriptor, CapaDescriptor):
+            return False
+
+        return dest_block.capa_type in child_descriptor.problem_types
+
     def update_children(self, dest_block, user_id, user_perms=None, update_db=True):
         """
         This method is to be used when any of the libraries that a LibraryContentModule
@@ -91,13 +104,16 @@ class LibraryToolsService(object):
             new_libraries = []
             for library_key, library in libraries:
 
-                def copy_children_recursively(from_block):
+                def copy_children_recursively(from_block, filter_problem_type=True):
                     """
                     Internal method to copy blocks from the library recursively
                     """
                     new_children = []
                     for child_key in from_block.children:
                         child = self.store.get_item(child_key, depth=9)
+
+                        if filter_problem_type and not self._filter_child(dest_block, child):
+                            continue
                         # We compute a block_id for each matching child block found in the library.
                         # block_ids are unique within any branch, but are not unique per-course or globally.
                         # We need our block_ids to be consistent when content in the library is updated, so
@@ -125,7 +141,7 @@ class LibraryToolsService(object):
                         )
                         new_children.append(new_child_info.location)
                     return new_children
-                root_children.extend(copy_children_recursively(from_block=library))
+                root_children.extend(copy_children_recursively(from_block=library, filter_problem_type=True))
                 new_libraries.append(LibraryVersionReference(library_key, library.location.library_key.version_guid))
             dest_block.source_libraries = new_libraries
             dest_block.children = root_children