Backport aiohttp conditional HEAD bug workaround

In older versions of aiohttp, HEAD requests don't mark the connection as
not reusable, which is why GET was used instead. But this means
`indices.exists` becomes `indices.get` which can be prohibitively slow
on indices with large mappings, so we want to use `HEAD` for aiohttp
versions that don't have this bug.

This backports the following pull requests to the 7.17 branch to make it
easier for Rally to upgrade to elasticsearch-py 8.x:

 * elastic/elastic-transport-python#55
 * elastic/elastic-transport-python#58

elasticsearch/_async/http_aiohttp.py

@@ -17,6 +17,7 @@
 
 import asyncio
 import os
+import re
 import ssl
 import warnings
 
@@ -49,6 +50,15 @@
 except ImportError:
     pass
 
+_version_parts = []
+for _version_part in aiohttp.__version__.split(".")[:3]:
+    try:
+        _version_parts.append(int(re.search(r"^([0-9]+)", _version_part).group(1)))  # type: ignore[union-attr]
+    except (AttributeError, ValueError):
+        break
+_AIOHTTP_SEMVER_VERSION = tuple(_version_parts)
+_AIOHTTP_FIXED_HEAD_BUG = _AIOHTTP_SEMVER_VERSION >= (3, 7, 0)
+
 
 class AsyncConnection(Connection):
     """Base class for Async HTTP connection implementations"""
@@ -247,11 +257,11 @@ async def perform_request(
             query_string = ""
             url_target = url_path
 
-        # There is a bug in aiohttp that disables the re-use
+        is_head = False
+        # There is a bug in aiohttp<3.7 that disables the re-use
         # of the connection in the pool when method=HEAD.
         # See: aio-libs/aiohttp#1769
-        is_head = False
-        if method == "HEAD":
+        if method == "HEAD" and not _AIOHTTP_FIXED_HEAD_BUG:
             method = "GET"
             is_head = True
 

test_elasticsearch/test_async/test_connection.py

@@ -29,6 +29,7 @@
 from mock import patch
 from multidict import CIMultiDict
 
+import elasticsearch._async.http_aiohttp
 from elasticsearch import AIOHttpConnection, AsyncElasticsearch, __versionstr__
 from elasticsearch.compat import reraise_exceptions
 from elasticsearch.exceptions import ConnectionError, NotFoundError
@@ -56,6 +57,9 @@ async def __aenter__(self, *_, **__):
                 async def __aexit__(self, *_, **__):
                     pass
 
+                async def release(self):
+                    pass
+
                 async def text(self):
                     return response_body.decode("utf-8", "surrogatepass")
 
@@ -421,6 +425,21 @@ def request_raise(*_, **__):
             await conn.perform_request("GET", "/")
         assert str(e.value) == "Wasn't modified!"
 
+    @pytest.mark.parametrize("aiohttp_fixed_head_bug", [True, False])
+    async def test_head_workaround(self, aiohttp_fixed_head_bug, monkeypatch):
+        monkeypatch.setattr(
+            elasticsearch._async.http_aiohttp,
+            "_AIOHTTP_FIXED_HEAD_BUG",
+            aiohttp_fixed_head_bug,
+        )
+
+        con = await self._get_mock_connection()
+        await con.perform_request("HEAD", "/anything")
+
+        method, url = con.session.request.call_args[0]
+        assert method == "HEAD" if aiohttp_fixed_head_bug else "GET"
+        assert url.human_repr() == "http://localhost:9200/anything"
+
 
 class TestConnectionHttpbin:
     """Tests the HTTP connection implementations against a live server E2E"""