fix(BA-5829): drop Fragment batch_load_by_ids; route loader through admin_search

Per review: the Fragment adapter's `batch_load_by_ids` duplicates the
search action; route the DataLoader through the existing
`admin_search` adapter method using the new `id_in` filter (added in
BA-5827) instead.

The DataLoader still preserves the input order and the Relay None-for-
missing contract.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: jopemachine

src/ai/backend/manager/api/adapters/app_config_fragment.py

@@ -2,9 +2,6 @@
 
 from __future__ import annotations
 
-import uuid
-from collections.abc import Sequence
-
 from ai.backend.common.contexts.user import current_user
 from ai.backend.common.dto.manager.v2.app_config.request import (
     AppConfigFilter,
@@ -77,7 +74,6 @@
 )
 from ai.backend.manager.repositories.base import (
     BatchQuerier,
-    OffsetPagination,
     QueryCondition,
     QueryOrder,
 )
@@ -128,31 +124,6 @@
 class AppConfigFragmentAdapter(BaseAdapter):
     """Adapter for AppConfigFragment domain operations (BEP-1052 §2)."""
 
-    async def batch_load_by_ids(
-        self, ids: Sequence[uuid.UUID]
-    ) -> list[AppConfigFragmentNode | None]:
-        """Batch-load fragments by id for DataLoader use.
-
-        Returns `AppConfigFragmentNode` DTOs in the same order as the
-        input `ids`, with `None` placeholders for rows that do not
-        exist (Relay batching contract). Goes through the cross-scope
-        search action because the scope-bound variant requires a single
-        `(scope_type, scope_id)` slice — DataLoader batches span
-        scopes. Authorization for the overall query is enforced at the
-        parent resolver before this loader is invoked.
-        """
-        if not ids:
-            return []
-        querier = BatchQuerier(
-            pagination=OffsetPagination(limit=len(ids)),
-            conditions=[AppConfigFragmentConditions.by_ids(ids)],
-        )
-        result = await self._processors.app_config_fragment.admin_search.wait_for_complete(
-            AdminSearchAppConfigFragmentsAction(querier=querier)
-        )
-        by_id = {item.id: self._data_to_dto(item) for item in result.items}
-        return [by_id.get(fragment_id) for fragment_id in ids]
-
     async def create(self, input: CreateAppConfigFragmentInput) -> CreateAppConfigFragmentPayload:
         key = self._input_to_key(input.key)
         result = await self._processors.app_config_fragment.create.wait_for_complete(

src/ai/backend/manager/api/gql/data_loader/data_loaders.py

@@ -123,12 +123,24 @@ def app_config_fragment_loader(
         adapter = self._adapters.app_config_fragment
 
         async def load_fn(ids: list[uuid.UUID]) -> list[AppConfigFragmentGQL | None]:
+            from ai.backend.common.dto.manager.v2.app_config_fragment.request import (  # pants: no-infer-dep
+                AppConfigFragmentFilter,
+                SearchAppConfigFragmentsInput,
+            )
             from ai.backend.manager.api.gql.app_config_fragment.types import (  # pants: no-infer-dep
                 AppConfigFragmentGQL as F,
             )
 
-            dtos = await adapter.batch_load_by_ids(ids)
-            return [F.from_pydantic(dto) if dto is not None else None for dto in dtos]
+            if not ids:
+                return []
+            payload = await adapter.admin_search(
+                SearchAppConfigFragmentsInput(
+                    filter=AppConfigFragmentFilter(id_in=list(ids)),
+                    limit=len(ids),
+                ),
+            )
+            by_id = {dto.id: F.from_pydantic(dto) for dto in payload.items}
+            return [by_id.get(fragment_id) for fragment_id in ids]
 
         return DataLoader(load_fn=load_fn)