Initial commit

env/lib/python3.10/site-packages/wagtail/models/copying.py

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+from django.contrib.contenttypes.fields import GenericRelation
+from django.db import models
+from modelcluster.fields import ParentalKey, ParentalManyToManyField
+from modelcluster.models import ClusterableModel
+
+
+def _extract_field_data(source, exclude_fields=None):
+    """
+    Get dictionaries representing the model's field data.
+
+    This excludes many to many fields (which are handled by _copy_m2m_relations)'
+    """
+    exclude_fields = exclude_fields or []
+    data_dict = {}
+
+    for field in source._meta.get_fields():
+        # Ignore explicitly excluded fields
+        if field.name in exclude_fields:
+            continue
+
+        # Ignore reverse relations
+        if field.auto_created:
+            continue
+
+        # Ignore reverse generic relations
+        if isinstance(field, GenericRelation):
+            continue
+
+        # Copy parental m2m relations
+        if field.many_to_many:
+            if isinstance(field, ParentalManyToManyField):
+                parental_field = getattr(source, field.name)
+                if hasattr(parental_field, "all"):
+                    values = parental_field.all()
+                    if values:
+                        data_dict[field.name] = values
+            continue
+
+        # Ignore parent links (page_ptr)
+        if isinstance(field, models.OneToOneField) and field.remote_field.parent_link:
+            continue
+
+        if isinstance(field, models.ForeignKey):
+            # Use attname to copy the ID instead of retrieving the instance
+
+            # Note: We first need to set the field to None to unset any object
+            # that's there already just setting _id on its own won't change the
+            # field until its saved.
+
+            data_dict[field.name] = None
+            data_dict[field.attname] = getattr(source, field.attname)
+
+        else:
+            data_dict[field.name] = getattr(source, field.name)
+
+    return data_dict
+
+
+def _copy_m2m_relations(source, target, exclude_fields=None, update_attrs=None):
+    """
+    Copies non-ParentalManyToMany m2m relations
+    """
+    update_attrs = update_attrs or {}
+    exclude_fields = exclude_fields or []
+
+    for field in source._meta.get_fields():
+        # Copy m2m relations. Ignore explicitly excluded fields, reverse relations, and Parental m2m fields.
+        if (
+            field.many_to_many
+            and field.name not in exclude_fields
+            and not field.auto_created
+            and not isinstance(field, ParentalManyToManyField)
+        ):
+            try:
+                # Do not copy m2m links with a through model that has a ParentalKey to the model being copied - these will be copied as child objects
+                through_model_parental_links = [
+                    field
+                    for field in field.through._meta.get_fields()
+                    if isinstance(field, ParentalKey)
+                    and issubclass(source.__class__, field.related_model)
+                ]
+                if through_model_parental_links:
+                    continue
+            except AttributeError:
+                pass
+
+            if field.name in update_attrs:
+                value = update_attrs[field.name]
+
+            else:
+                value = getattr(source, field.name).all()
+
+            getattr(target, field.name).set(value)
+
+
+def _copy(source, exclude_fields=None, update_attrs=None):
+    data_dict = _extract_field_data(source, exclude_fields=exclude_fields)
+    target = source.__class__(**data_dict)
+
+    if update_attrs:
+        for field, value in update_attrs.items():
+            if field not in data_dict:
+                continue
+            setattr(target, field, value)
+
+    if isinstance(source, ClusterableModel):
+        child_object_map = source.copy_all_child_relations(
+            target, exclude=exclude_fields
+        )
+    else:
+        child_object_map = {}
+
+    return target, child_object_map