fix: remove skip from subsequent pages

Author: ricellis

ibmcloudant/features/pagination.py

@@ -263,7 +263,7 @@ class _BasePageIterator(Iterator[Sequence[I]]):
   def __init__(self,
                client: CloudantV1,
                operation: Callable[..., DetailedResponse],
-               page_opts: list[str],
+               page_opts: Sequence[str],
                opts: dict):
     self._client: CloudantV1 = client
     self._has_next: bool = True
@@ -318,7 +318,7 @@ def _get_next_page_options(self, result: R) -> dict:
 class _KeyPageIterator(_BasePageIterator, Generic[K]):
 
   def __init__(self, client: CloudantV1, operation: Callable[..., DetailedResponse], opts: dict):
-    super().__init__(client, operation, ['start_key', 'start_key_doc_id'], opts)
+    super().__init__(client, operation, ('skip', 'start_key', 'start_key_doc_id',), opts)
     self._boundary_failure: Optional[str] = None
 
   def _next_request(self) -> list[I]:
@@ -353,8 +353,8 @@ def check_boundary(self, penultimate_item: I, last_item: I) -> Optional[str]:
 
 class _BookmarkPageIterator(_BasePageIterator):
 
-  def __init__(self, client: CloudantV1, operation: Callable[..., DetailedResponse], opts: dict):
-    super().__init__(client, operation, ['bookmark'], opts)
+  def __init__(self, client: CloudantV1, operation: Callable[..., DetailedResponse], opts: dict, extra_page_opts:Sequence[str]=()):
+    super().__init__(client, operation, ('bookmark',) + extra_page_opts, opts)
 
   def _get_next_page_options(self, result: R) -> dict:
     return {'bookmark': result.bookmark}
@@ -391,6 +391,12 @@ def __init__(self, client: CloudantV1, opts: dict):
 
 class _FindBasePageIterator(_BookmarkPageIterator):
 
+  def __init__(self, client: CloudantV1, operation: Callable[..., DetailedResponse], opts: dict):
+    # Find requests allow skip, but it should only be used on the first request.
+    # Since we don't want it on subsequent page requests we need to exclude it from
+    # fixed opts used for the partial function.
+    super().__init__(client, operation, opts, extra_page_opts=('skip',))
+
   def _items(self, result: FindResult):
     return result.docs
 

test/unit/features/test_pagination_operations.py

@@ -191,3 +191,17 @@ def test_rows_errors(self):
                   for row in Pagination.new_pagination(self.client, pager_type, limit=page_size).rows():
                     actual_item_count += 1
                 self.assertEqual(actual_item_count, expected_item_count, 'Should have got the correct number of items before error.')
+
+  # Test skip omitted from subsequent page requests
+  # Applies to key pagers and find pagers
+  def test_skip_removed_for_subsquent_page(self):
+    page_size = 14
+    for pager_type in (PaginationMockSupport.key_pagers + PaginationMockSupport.find_pagers):
+      with self.subTest(pager_type):
+        with patch(PaginationMockSupport.operation_map[pager_type], PaginationMockResponse(2*page_size, page_size, pager_type).get_next_page):
+          pager = Pagination.new_pagination(self.client, pager_type, limit=page_size, skip=1).pager()
+          # Assert first page has skip option
+          self.assertEqual(pager._iterator._next_page_opts['skip'], 1, 'The skip option should be 1 for the first page')
+          pager.get_next()
+          # Assert second page has no skip option
+          self.assertIsNone(pager._iterator._next_page_opts.get('skip'), 'The skip option should be absent for the next page')