Fix missing relations for models with ManyToManyField fields (#205)

Author: droserasprout

CHANGELOG.md

@@ -7,6 +7,7 @@ Please use [this](https://docs.gitlab.com/ee/development/changelog.html) documen
 ### Fixed
 
 * demos: Tezos Domains and Homebase DAO demos were updated from edo2net to mainnet contracts.
+* hasura: Fixed missing relations for models with `ManyToManyField` fields.
 
 ### Performance
 

poetry.lock

@@ -274,20 +274,53 @@ async def _generate_source_tables_metadata(self) -> List[Dict[str, Any]]:
                 if isinstance(field, fields.relational.ForeignKeyFieldInstance):
                     if not isinstance(field.related_name, str):
                         raise HasuraError(f'`related_name` of `{field}` must be set')
+
                     related_table_name = model_tables[field.model_name]
+                    field_name = field.model_field_name
                     metadata_tables[table_name]['object_relationships'].append(
                         self._format_object_relationship(
-                            name=field.model_field_name,
-                            column=field.model_field_name + '_id',
+                            name=field_name,
+                            column=field_name + '_id',
                         )
                     )
                     metadata_tables[related_table_name]['array_relationships'].append(
                         self._format_array_relationship(
                             related_name=field.related_name,
                             table=table_name,
-                            column=field.model_field_name + '_id',
+                            column=field_name + '_id',
+                        )
+                    )
+
+                elif isinstance(field, fields.relational.ManyToManyFieldInstance):
+                    if not isinstance(field.related_name, str):
+                        raise HasuraError(f'`related_name` of `{field}` must be set')
+
+                    related_table_name = model_tables[field.model_name]
+                    junction_table_name = field.through
+
+                    metadata_tables[junction_table_name] = self._format_table(junction_table_name)
+                    metadata_tables[junction_table_name]['object_relationships'].append(
+                        self._format_object_relationship(
+                            name=related_table_name,
+                            column=related_table_name + '_id',
                         )
                     )
+                    metadata_tables[junction_table_name]['object_relationships'].append(
+                        self._format_object_relationship(
+                            name=table_name,
+                            column=table_name + '_id',
+                        )
+                    )
+                    metadata_tables[related_table_name]['array_relationships'].append(
+                        self._format_array_relationship(
+                            related_name=f'{related_table_name}_{field.related_name}',
+                            table=junction_table_name,
+                            column=related_table_name + '_id',
+                        )
+                    )
+
+                else:
+                    pass
 
         return list(metadata_tables.values())