Add a base_version filter

CHANGES/+base-version-content-filter.feature

@@ -0,0 +1,6 @@
+Added a ``base_version`` filter to the content list endpoints. When combined with
+``repository_version_added`` or ``repository_version_removed``, it returns the net set of content
+added or removed between two arbitrary repository versions instead of only the single-step
+difference against the filtered version's immediate predecessor. The diff is computed database-side
+via ``unnest`` subqueries over each version's ``content_ids``, avoiding loading the arrays into
+memory or passing them as per-query parameters.

pulpcore/app/models/repository.py

@@ -1000,13 +1000,26 @@ def get_content(self, content_qs=None):
         content_ids = self.content_ids
         if len(content_ids) >= 65535:
             # Workaround for PostgreSQL's limit on the number of parameters in a query
-            content_ids = (
-                RepositoryVersion.objects.filter(pk=self.pk)
-                .annotate(cids=Func(F("content_ids"), function="unnest"))
-                .values_list("cids", flat=True)
-            )
+            content_ids = self.content_ids_subquery()
         return content_qs.filter(pk__in=content_ids)
 
+    def content_ids_subquery(self):
+        """
+        Return this version's ``content_ids`` as a database-side ``unnest`` subquery.
+
+        Using a subquery keeps the content unit UUIDs inside PostgreSQL instead of loading the
+        whole array into Python and passing each UUID as a bound query parameter. This avoids the
+        per-query parameter limit and the memory/serialization cost for large repository versions.
+
+        Returns:
+            django.db.models.QuerySet: A values queryset yielding the content unit UUIDs.
+        """
+        return (
+            RepositoryVersion.objects.filter(pk=self.pk)
+            .annotate(cids=Func(F("content_ids"), function="unnest"))
+            .values_list("cids", flat=True)
+        )
+
     @property
     def content(self):
         """
@@ -1119,8 +1132,8 @@ def added(self, base_version=None):
         if not base_version:
             return Content.objects.filter(version_memberships__version_added=self)
 
-        return Content.objects.filter(pk__in=self.content_ids).exclude(
-            pk__in=base_version.content_ids
+        return Content.objects.filter(pk__in=self.content_ids_subquery()).exclude(
+            pk__in=base_version.content_ids_subquery()
         )
 
     def removed(self, base_version=None):
@@ -1134,8 +1147,8 @@ def removed(self, base_version=None):
         if not base_version:
             return Content.objects.filter(version_memberships__version_removed=self)
 
-        return Content.objects.filter(pk__in=base_version.content_ids).exclude(
-            pk__in=self.content_ids
+        return Content.objects.filter(pk__in=base_version.content_ids_subquery()).exclude(
+            pk__in=self.content_ids_subquery()
         )
 
     def contains(self, content):

pulpcore/app/viewsets/content.py

@@ -23,6 +23,7 @@
     ContentAddedRepositoryVersionFilter,
     ContentRemovedRepositoryVersionFilter,
     ContentRepositoryVersionFilter,
+    RepositoryVersionBaseFilter,
 )
 
 
@@ -125,6 +126,10 @@ class ContentFilter(BaseFilterSet):
             Return Content which was added in this repository version.
         repository_version_removed:
             Return Content which was removed from this repository version.
+        base_version:
+            When combined with repository_version_added / repository_version_removed, compute the
+            net difference relative to this base repository version instead of the filtered
+            version's immediate predecessor. Has no effect on its own.
         orphaned_for:
             Return Content which has been orphaned for a given number of minutes;
             -1 uses ORPHAN_PROTECTION_TIME value.
@@ -135,6 +140,7 @@ class ContentFilter(BaseFilterSet):
     repository_version = ContentRepositoryVersionFilter()
     repository_version_added = ContentAddedRepositoryVersionFilter()
     repository_version_removed = ContentRemovedRepositoryVersionFilter()
+    base_version = RepositoryVersionBaseFilter()
     orphaned_for = OrphanedFilter(
         help_text="Minutes Content has been orphaned for. -1 uses ORPHAN_PROTECTION_TIME."
     )

pulpcore/app/viewsets/custom_filters.py

@@ -162,6 +162,53 @@ def filter(self, qs, value):
         """
         raise NotImplementedError()
 
+    def get_base_version(self, field_name="base_version"):
+        """
+        Resolve the companion ``base_version`` filter, if the request supplied one.
+
+        The added/removed filters use this to diff against an *arbitrary* base repository
+        version instead of the filtered version's immediate predecessor.
+
+        Args:
+            field_name (string): The name of the companion base-version filter on the filterset.
+
+        Returns:
+            pulpcore.app.models.RepositoryVersion or None: The resolved base version, or None
+            when no base version was supplied.
+        """
+        if self.parent is None:
+            return None
+        base_value = self.parent.form.cleaned_data.get(field_name)
+        if not base_value:
+            return None
+        return self.get_repository_version(base_value)
+
+
+class RepositoryVersionBaseFilter(RepoVersionHrefPrnFilter):
+    """
+    Companion filter that designates the base repository version for
+    ``repository_version_added`` / ``repository_version_removed`` diffs.
+
+    On its own this filter does not alter the queryset. It is consumed by the added/removed
+    filters to compute the net difference between two arbitrary repository versions, rather than
+    the single-step difference against the filtered version's immediate predecessor.
+    """
+
+    def __init__(self, *args, **kwargs):
+        kwargs.setdefault(
+            "help_text",
+            _(
+                "Repository Version referenced by HREF/PRN to use as the base for "
+                "repository_version_added / repository_version_removed. When set, added/removed "
+                "content is computed relative to this version instead of the immediate predecessor."
+            ),
+        )
+        super().__init__(*args, **kwargs)
+
+    def filter(self, qs, value):
+        # No-op on its own; the value is consumed by the added/removed filters.
+        return qs
+
 
 class RepositoryVersionFilter(RepoVersionHrefPrnFilter):
     """
@@ -251,7 +298,7 @@ def filter(self, qs, value):
             return qs
 
         repo_version = self.get_repository_version(value)
-        return qs.filter(pk__in=repo_version.added())
+        return qs.filter(pk__in=repo_version.added(base_version=self.get_base_version()))
 
 
 class ContentRemovedRepositoryVersionFilter(RepoVersionHrefPrnFilter):
@@ -273,7 +320,7 @@ def filter(self, qs, value):
             return qs
 
         repo_version = self.get_repository_version(value)
-        return qs.filter(pk__in=repo_version.removed())
+        return qs.filter(pk__in=repo_version.removed(base_version=self.get_base_version()))
 
 
 class CharInFilter(BaseInFilter, CharFilter):