Fixing errors uncovered by linting

Author: alyjak

django_postgresql_dag/__init__.py

@@ -23,3 +23,10 @@ class IncorrectUsageException(Exception):
     """
 
     pass
+
+class IncorrectQuerysetTypeException(Exception):
+    """
+    Exception for mismatch between helper method and queryset arg
+    """
+
+    pass

django_postgresql_dag/exceptions.py

@@ -6,14 +6,18 @@
 """
 
 from copy import deepcopy
-from django.apps import apps
-from django.db import models, connection
-from django.db.models import Case, When
+from django.db import models
 from django.core.exceptions import ValidationError
 
 from .exceptions import NodeNotReachableException
 from .utils import _ordered_filter
-from .query_builders import AncestorQuery, DescendantQuery, UpwardPathQuery, DownwardPathQuery, ConnectedGraphQuery
+from .query_builders import (
+    AncestorQuery,
+    DescendantQuery,
+    UpwardPathQuery,
+    DownwardPathQuery,
+    ConnectedGraphQuery
+)
 
 
 class NodeManager(models.Manager):
@@ -53,18 +57,6 @@ class Node(base_model):
         class Meta:
             abstract = True
 
-        def get_foreign_key_field(self, fk_instance=None):
-            """
-            Provided a model instance, checks if the edge model has a ForeignKey field to the
-            model class of that instance, and then returns the associated field name, else None.
-            """
-            if fk_instance is not None:
-                for field in edge_model._meta.get_fields():
-                    if field.related_model is fk_instance._meta.model:
-                        # Return the first field that matches
-                        return field.name
-            return None
-
         def get_pk_name(self):
             """Sometimes we set a field other than 'pk' for the primary key.
             This method is used to get the correct primary key field name for the

django_postgresql_dag/models.py

@@ -1,6 +1,7 @@
 from abc import ABC, abstractmethod
 from django.core.exceptions import ImproperlyConfigured
-from .utils import get_instance_characteristics, get_queryset_characteristics
+
+from .utils import get_foreign_key_field, get_instance_characteristics
 
 
 class BaseQuery(ABC):
@@ -198,7 +199,7 @@ def _limit_to_edges_set_fk(self):
             """AND {relationship_table}.{fk_field_name}_id = %(limiting_edges_set_fk_pk)s"""
         )
 
-        fk_field_name = get_foreign_key_field(fk_instance=self.limiting_edges_set_fk)
+        fk_field_name = get_foreign_key_field(self.edge_model, self.limiting_edges_set_fk)
         if fk_field_name is not None:
             self.where_clauses_part_1 += "\n" + LIMITING_EDGES_SET_FK_CLAUSE_1.format(
                 relationship_table=self.edge_model_table,
@@ -316,7 +317,7 @@ def _limit_to_edges_set_fk(self):
             """AND {relationship_table}.{fk_field_name}_id = %(limiting_edges_set_fk_pk)s"""
         )
 
-        fk_field_name = get_foreign_key_field(fk_instance=self.limiting_edges_set_fk)
+        fk_field_name = get_foreign_key_field(self.edge_model, self.limiting_edges_set_fk)
         if fk_field_name is not None:
             self.where_clauses_part_1 += "\n" + LIMITING_EDGES_SET_FK_CLAUSE_1.format(
                 relationship_table=self.edge_model_table,
@@ -482,7 +483,7 @@ def _limit_to_nodes_set_fk(self):
     def _limit_to_edges_set_fk(self):
         LIMITING_EDGES_SET_FK_CLAUSE = """AND first.{fk_field_name}_id = %(limiting_edges_set_fk_pk)s"""
 
-        fk_field_name = get_foreign_key_field(fk_instance=self.limiting_edges_set_fk)
+        fk_field_name = get_foreign_key_field(self.edge_model, self.limiting_edges_set_fk)
         if fk_field_name is not None:
             self.where_clauses_part_2 += "\n" + LIMITING_EDGES_SET_FK_CLAUSE.format(
                 relationship_table=self.edge_model_table,
@@ -584,7 +585,7 @@ def _limit_to_nodes_set_fk(self):
     def _limit_to_edges_set_fk(self):
         LIMITING_EDGES_SET_FK_CLAUSE = """AND first.{fk_field_name}_id = %(limiting_edges_set_fk_pk)s"""
 
-        fk_field_name = get_foreign_key_field(fk_instance=self.limiting_edges_set_fk)
+        fk_field_name = get_foreign_key_field(self.edge_model, self.limiting_edges_set_fk)
         if fk_field_name is not None:
             self.where_clauses_part_2 += "\n" + LIMITING_EDGES_SET_FK_CLAUSE.format(
                 relationship_table=self.edge_model_table,

django_postgresql_dag/query_builders.py

@@ -4,10 +4,8 @@
 """
 
 import networkx as nx
-import pandas as pd
 
 from .utils import (
-    _ordered_filter,
     get_queryset_characteristics,
     model_to_dict,
     edges_from_nodes_queryset,

django_postgresql_dag/transformations.py

@@ -1,5 +1 @@
-from django.conf import settings
-from django.conf.urls.static import static
-from django.urls import include, path, re_path
-
 urlpatterns = []

django_postgresql_dag/urls.py

@@ -2,17 +2,20 @@
 Functions for transforming RawQuerySet or other outputs of
 django-postgresql-dag to alternate formats.
 """
-
+import inspect
 from itertools import chain
 
-
 from django.core.exceptions import FieldDoesNotExist
 from django.db.models import Case, When
 from django.db.models.fields import DateTimeField, UUIDField
 from django.db.models.fields.files import FileField, ImageField
 from django.db.models.fields.related import ManyToManyField
 
-from .exceptions import GraphModelsCannotBeParsedException, IncorrectUsageException
+from .exceptions import (
+    GraphModelsCannotBeParsedException,
+    IncorrectUsageException,
+    IncorrectQuerysetTypeException
+)
 
 
 def _ordered_filter(queryset, field_names, values):
@@ -57,6 +60,18 @@ def get_instance_characteristics(instance):
     return (_NodeModel, _EdgeModel, instance_type)
 
 
+def get_foreign_key_field(edge_model, fk_instance):
+    """
+    Provided a model instance, checks if the edge model has a ForeignKey field to the
+    model class of that instance, and then returns the associated field name, else None.
+    """
+    for field in edge_model._meta.get_fields():
+        if field.related_model is fk_instance._meta.model:
+            # Return the first field that matches
+            return field.name
+    return None
+
+
 def get_queryset_characteristics(queryset):
     """
     Returns a tuple of the node & edge model classes and the queryset type