workflows: allow Django templates in OpenDocument image references (#55361)

tests/test_workflows.py

@@ -3757,7 +3757,10 @@ def test_transform_to_pdf():
         assert outstream.read(10).startswith(b'%PDF-')
 
 
-def test_export_to_model_image(pub):
+@pytest.mark.parametrize(
+    'template_name', ['template-with-image.odt', 'template-with-image-django-syntax.odt']
+)
+def test_export_to_model_image(pub, template_name):
     formdef = FormDef()
     formdef.name = 'baz'
     formdef.fields = [
@@ -3779,7 +3782,7 @@ def test_export_to_model_image(pub):
     item = ExportToModel()
     item.convert_to_pdf = False
     item.method = 'non-interactive'
-    template_filename = os.path.join(os.path.dirname(__file__), 'template-with-image.odt')
+    template_filename = os.path.join(os.path.dirname(__file__), template_name)
     with open(template_filename, 'rb') as fd:
         template = fd.read()
     upload = QuixoteUpload('/foo/template.odt', content_type='application/octet-stream')

wcs/wf/export_to_model.py

@@ -587,17 +587,18 @@ class ExportToModel(WorkflowStatusItem):
 
                 if node.tag == DRAW_FRAME:
                     name = node.attrib.get(DRAW_NAME)
-                    if not self.get_expression(name)['type'] == 'python':
-                        continue
                     # variable image
-                    try:
-                        variable_image = self.compute(name)
-                    except Exception:
-                        continue
-                    if not hasattr(variable_image, 'get_content'):
+                    pub = get_publisher()
+                    with pub.complex_data():
+                        try:
+                            variable_image = self.compute(name, allow_complex=True)
+                        except Exception:
+                            continue
+                        complex_variable_image = get_publisher().get_cached_complex_data(variable_image)
+                    if not hasattr(complex_variable_image, 'get_content'):
                         continue
                     image = [x for x in node if x.tag == DRAW_IMAGE][0]
-                    new_images[image.attrib.get(XLINK_HREF)] = variable_image
+                    new_images[image.attrib.get(XLINK_HREF)] = complex_variable_image
 
                 for attr in ('text', 'tail'):
                     if not getattr(node, attr):