Warn when slicing twice (elastic#1775)

Author: pquentin

elasticsearch_dsl/search_base.py

@@ -17,6 +17,7 @@
 
 import collections.abc
 import copy
+import warnings
 
 from .aggs import A, AggBase
 from .exceptions import IllegalOperation
@@ -348,6 +349,15 @@ def __getitem__(self, n):
         """
         s = self._clone()
 
+        if "from" in s._extra or "size" in s._extra:
+            warnings.warn(
+                "Slicing multiple times currently has no effect but will be supported "
+                "in a future release. See https://github.com/elastic/elasticsearch-dsl-py/pull/1771 "
+                "for more details",
+                DeprecationWarning,
+                stacklevel=2,
+            )
+
         if isinstance(n, slice):
             # If negative slicing, abort.
             if n.start and n.start < 0 or n.stop and n.stop < 0:

tests/_async/test_search.py

@@ -17,7 +17,7 @@
 
 from copy import deepcopy
 
-from pytest import raises
+from pytest import raises, warns
 
 from elasticsearch_dsl import AsyncSearch, Document, Q, query
 from elasticsearch_dsl.exceptions import IllegalOperation
@@ -363,6 +363,12 @@ def test_slice():
     assert {"from": 20, "size": 0} == s[20:0].to_dict()
 
 
+def test_slice_twice():
+    with warns(DeprecationWarning, match="Slicing multiple times .*"):
+        s = AsyncSearch()
+        s[10:20][2:]
+
+
 def test_index():
     s = AsyncSearch()
     assert {"from": 3, "size": 1} == s[3].to_dict()

tests/_sync/test_search.py

@@ -17,7 +17,7 @@
 
 from copy import deepcopy
 
-from pytest import raises
+from pytest import raises, warns
 
 from elasticsearch_dsl import Document, Q, Search, query
 from elasticsearch_dsl.exceptions import IllegalOperation
@@ -363,6 +363,12 @@ def test_slice():
     assert {"from": 20, "size": 0} == s[20:0].to_dict()
 
 
+def test_slice_twice():
+    with warns(DeprecationWarning, match="Slicing multiple times .*"):
+        s = Search()
+        s[10:20][2:]
+
+
 def test_index():
     s = Search()
     assert {"from": 3, "size": 1} == s[3].to_dict()