Fix index rebuilding for multi value first levels. GitLab issue #391.

Thanks to @jacekkow for the report and diagnosis.

Signed-off-by: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>

HISTORY.rst

@@ -9,7 +9,8 @@ XX (2017-XX-XX)
 - Make tags, metadata types and cabinets searchable via the dynamic search API. GitLab issue #344.
 - Add support for updating configuration options from environment variables.
 - Add purgelocks management command. GitLab issue #221.
- 
+- Fix index rebuilding for multi value first levels. GitLab issue #391. 
+
 2.3 (2017-06-08)
 ================
 - Allow for bigger indexing expression templates.

mayan/apps/document_indexing/models.py

@@ -179,8 +179,8 @@ class IndexTemplateNode(MPTTModel):
         else:
             return self.expression
 
-    def index_document(self, document, acquire_lock=True):
-        # Avoid another process to index this same document for the same
+    def index_document(self, document, acquire_lock=True, index_instance_node_parent=None):
+        # Avoid another process indexing this same document for the same
         # template node. This prevents this template node's index instance
         # nodes from being deleted while the template is evaluated and
         # documents added to it.
@@ -211,16 +211,20 @@ class IndexTemplateNode(MPTTModel):
                 index_instance_node, created = self.index_instance_nodes.get_or_create()
 
                 for child in self.get_children():
-                    child.index_document(document=document, acquire_lock=False)
+                    child.index_document(
+                        document=document, acquire_lock=False,
+                        index_instance_node_parent=index_instance_node
+                    )
 
                 if acquire_lock:
                     lock.release()
 
             elif self.enabled:
                 logger.debug('IndexTemplateNode; non parent: evaluating')
-                logger.debug('My parent is: %s', self.parent)
+                logger.debug('My parent template is: %s', self.parent)
                 logger.debug(
-                    'My parent nodes: %s', self.parent.index_instance_nodes.all()
+                    'My parent instance node is: %s',
+                    index_instance_node_parent
                 )
                 logger.debug(
                     'IndexTemplateNode; Evaluating template: %s', self.expression
@@ -245,14 +249,17 @@ class IndexTemplateNode(MPTTModel):
                     logger.debug('Evaluation result: %s', result)
                     if result:
                         index_instance_node, created = self.index_instance_nodes.get_or_create(
-                            parent=self.parent.index_instance_nodes.get(),
+                            parent=index_instance_node_parent,
                             value=result
                         )
                         if self.link_documents:
                             index_instance_node.documents.add(document)
 
                     for child in self.get_children():
-                        child.index_document(document=document, acquire_lock=False)
+                        child.index_document(
+                            document=document, acquire_lock=False,
+                            index_instance_node_parent=index_instance_node
+                        )
                 finally:
                     if acquire_lock:
                         lock.release()

mayan/apps/document_indexing/tests/test_models.py

@@ -1,6 +1,7 @@
 from __future__ import unicode_literals
 
 from django.test import override_settings
+from django.utils.encoding import force_text
 
 from common.tests import BaseTestCase
 from documents.models import DocumentType
@@ -169,3 +170,42 @@ class IndexTestCase(BaseTestCase):
         self.assertQuerysetEqual(
             instance_node.documents.all(), [repr(self.document)]
         )
+
+    def test_dual_level_dual_document_index(self):
+        """
+        Test creation of an index instance with two first levels with different
+        values and two second levels with the same value but as separate
+        children of each of the first levels.
+        """
+        with open(TEST_SMALL_DOCUMENT_PATH) as file_object:
+            self.document_2 = self.document_type.new_document(
+                file_object=file_object
+            )
+
+        # Create empty index
+        index = Index.objects.create(label=TEST_INDEX_LABEL)
+
+        # Add our document type to the new index
+        index.document_types.add(self.document_type)
+
+        # Create simple index template
+        root = index.template_root
+        level_1 = index.node_templates.create(
+            parent=root, expression='{{ document.uuid }}',
+            link_documents=False
+        )
+
+        index.node_templates.create(
+            parent=level_1, expression='{{ document.label }}',
+            link_documents=True
+        )
+
+        Index.objects.rebuild()
+
+        self.assertEqual(
+            [instance.value for instance in IndexInstanceNode.objects.all()],
+            [
+                '', force_text(self.document_2.uuid), self.document_2.label,
+                force_text(self.document.uuid), self.document.label
+            ]
+        )