Migration from Ubuntu 17.04 / Django 1.11 to Ubuntu 20.04 / Django 3.1

datatableview/columns.py

@@ -11,9 +11,8 @@
 import django
 from django.db import models
 from django.db.models import Model, Manager, Q
-from django.db.models.fields import FieldDoesNotExist
-from django.core.exceptions import ObjectDoesNotExist
-from django.utils.encoding import smart_text
+from django.core.exceptions import ObjectDoesNotExist, FieldDoesNotExist
+from django.utils.encoding import smart_str
 from django.utils.safestring import mark_safe
 try:
     from django.forms.utils import flatatt
@@ -24,6 +23,7 @@
     from django.utils.encoding import python_2_unicode_compatible
 except ImportError:
     from .compat import python_2_unicode_compatible
+from .compat import get_rel_to
 
 import six
 import dateutil.parser
@@ -56,8 +56,11 @@ def get_column_for_modelfield(model_field):
     # that as the real field.  It is possible that a ForeignKey points to a model with table
     # inheritance, however, so we need to traverse the internal OneToOneField as well, so this will
     # climb the 'pk' field chain until we have something real.
-    while model_field.rel:
-        model_field = model_field.rel.to._meta.pk
+    rel_to = get_rel_to(model_field)
+    while rel_to:
+        model_field = rel_to._meta.pk
+        rel_to = get_rel_to(model_field)
+
     for ColumnClass, modelfield_classes in COLUMN_CLASSES:
         if isinstance(model_field, tuple(modelfield_classes)):
             return ColumnClass
@@ -112,13 +115,13 @@ def __init__(self, label=None, sources=None, processor=None, source=None,
 
         self.name = None  # Set outside, once the Datatable can put it there
         if label is not None:
-            label = smart_text(label)
+            label = smart_str(label)
         self.sources = sources or []  # TODO: Process for real/virtual
         if not isinstance(self.sources, (tuple, list)):
             self.sources = [self.sources]
         self.separator = separator
         self.label = label
-        self.empty_value = smart_text(empty_value)
+        self.empty_value = smart_str(empty_value)
         self.localize = localize
         self.sortable = sortable
         self.visible = visible

datatableview/compat.py

@@ -43,3 +43,13 @@ def escape_uri_path(path):
     if django_escape_uri_path:
         return django_escape_uri_path(path)
     return escape(path)
+
+def get_rel_to(model_field):
+    # as per https://gist.github.com/ofalk/404f9f637b7b4520e26dcdd520dbe248
+    rel_to = None
+    if hasattr(model_field, 'rel'):
+        rel_to = model_field.rel.to if model_field.rel else None
+    elif hasattr(model_field, 'remote_field'):
+        rel_to = model_field.remote_field.model if model_field.remote_field else None
+    return rel_to
+

datatableview/datatables.py

@@ -9,7 +9,7 @@
 except ImportError:
     pass
 
-from django.db.models.fields import FieldDoesNotExist
+from django.core.exceptions import FieldDoesNotExist
 from django.template.loader import render_to_string
 from django.db.models import QuerySet
 try:

datatableview/utils.py

@@ -6,7 +6,7 @@
     pass
 
 from django.db import models
-from django.db.models.fields import FieldDoesNotExist
+from django.core.exceptions import FieldDoesNotExist
 from django.utils.text import smart_split
 try:
     from django.db.models.related import RelatedObject
@@ -15,7 +15,7 @@
     from django.db.models.fields.related import RelatedField
     USE_RELATED_OBJECT = False
 
-from .compat import get_field
+from .compat import get_field, get_rel_to
 
 MINIMUM_PAGE_LENGTH = 1
 DEFAULT_EMPTY_VALUE = ""
@@ -63,7 +63,7 @@
 def resolve_orm_path(model, orm_path):
     """
     Follows the queryset-style query path of ``orm_path`` starting from ``model`` class.  If the
-    path ends up referring to a bad field name, ``django.db.models.fields.FieldDoesNotExist`` will
+    path ends up referring to a bad field name, ``django.core.exceptions.FieldDoesNotExist`` will
     be raised.
 
     """
@@ -96,11 +96,12 @@ def get_model_at_related_field(model, attr):
             # -- Django <1.8 mode
             return field.model
 
-    if hasattr(field, 'rel') and field.rel:  # Forward/m2m relationship
-        return field.rel.to
+    rel_to = get_rel_to(field)
+    if rel_to:  # Forward/m2m relationship
+        return rel_to
 
     if hasattr(field, 'field'):  # Forward GenericForeignKey in Django 1.6+
-        return field.field.rel.to
+        return get_rel_to(field.field)
 
     raise ValueError("{0}.{1} ({2}) is not a relationship field.".format(model.__name__, attr,
                                                                          field.__class__.__name__))