fix: don't forbid all PQexec queries in client-side cursors

We can still use PQexecParams with an empty list of parameters. This has
advantages, such as the possibility of implementing stream(), and less
faffing with differences between Cursor and ClientCursor.

diff --git a/psycopg/psycopg/client_cursor.py b/psycopg/psycopg/client_cursor.py
index 851b1cec6830bef2214c04f7b6099980b8db9793..a61d10234383977e7248fbd34be943248a1f7d4d 100644 (file)
--- a/psycopg/psycopg/client_cursor.py
+++ b/psycopg/psycopg/client_cursor.py
@@ -49,20 +49,23 @@ class ClientCursorMixin(BaseCursor[ConnectionType, Row]):
                 "client-side cursors don't support binary results"
             )
 
-        if no_pqexec:
-            raise e.NotSupportedError(
-                "PQexec operations not supported by client-side cursors"
-            )
-
         self._query = query
-        # if we don't have to, let's use exec_ as it can run more than
-        # one query in one go
-        if self._conn._pipeline:
-            self._conn._pipeline.command_queue.append(
-                partial(self._pgconn.send_query, query.query)
-            )
+        if no_pqexec:
+            if self._conn._pipeline:
+                self._conn._pipeline.command_queue.append(
+                    partial(self._pgconn.send_query_params, None)
+                )
+            else:
+                self._pgconn.send_query_params(query.query, None)
         else:
-            self._pgconn.send_query(query.query)
+            # if we don't have to, let's use exec_ as it can run more than
+            # one query in one go
+            if self._conn._pipeline:
+                self._conn._pipeline.command_queue.append(
+                    partial(self._pgconn.send_query, query.query)
+                )
+            else:
+                self._pgconn.send_query(query.query)
 
     def _convert_query(
         self, query: Query, params: Optional[Params] = None
@@ -76,9 +79,6 @@ class ClientCursorMixin(BaseCursor[ConnectionType, Row]):
     ) -> Tuple[Prepare, bytes]:
         return (Prepare.NO, b"")
 
-    def _is_pipeline_supported(self) -> bool:
-        return False
-
 
 class ClientCursor(ClientCursorMixin["Connection[Row]", Row], Cursor[Row]):
     pass

diff --git a/psycopg/psycopg/cursor.py b/psycopg/psycopg/cursor.py
index 12db07a3fcc0ea727948eaaae400d9c63d377695..26d1611434558ef78bfaf04ad91f2499339e294b 100644 (file)
--- a/psycopg/psycopg/cursor.py
+++ b/psycopg/psycopg/cursor.py
@@ -726,7 +726,7 @@ class Cursor(BaseCursor["Connection[Any]", Row]):
         Execute the same command with a sequence of input data.
         """
         try:
-            if self._is_pipeline_supported():
+            if Pipeline.is_supported():
                 # If there is already a pipeline, ride it, in order to avoid
                 # sending unnecessary Sync.
                 with self._conn.lock:
@@ -749,9 +749,6 @@ class Cursor(BaseCursor["Connection[Any]", Row]):
         except e.Error as ex:
             raise ex.with_traceback(None)
 
-    def _is_pipeline_supported(self) -> bool:
-        return Pipeline.is_supported()
-
     def stream(
         self,
         query: Query,

diff --git a/tests/test_client_cursor.py b/tests/test_client_cursor.py
index dc5b22edb21ac64730aadf1a65074649b1d9261f..c2db78750d1f188f8033bdacd685fa52aaa988ce 100644 (file)
--- a/tests/test_client_cursor.py
+++ b/tests/test_client_cursor.py
@@ -583,12 +583,14 @@ def test_query_params_executemany(conn):
 
 def test_stream(conn):
     cur = conn.cursor()
-    with pytest.raises(psycopg.NotSupportedError):
-        for rec in cur.stream(
-            "select i, '2021-01-01'::date + i from generate_series(1, %s) as i",
-            [2],
-        ):
-            pass
+    recs = []
+    for rec in cur.stream(
+        "select i, '2021-01-01'::date + i from generate_series(1, %s) as i",
+        [2],
+    ):
+        recs.append(rec)
+
+    assert recs == [(1, dt.date(2021, 1, 2)), (2, dt.date(2021, 1, 3))]
 
 
 class TestColumn:

diff --git a/tests/test_client_cursor_async.py b/tests/test_client_cursor_async.py
index f4d7dc8bb3ab854fbf344f3b7b635d15eb2362d6..af8307ac94f709ec4ca873ee655dc1bce41a627e 100644 (file)
--- a/tests/test_client_cursor_async.py
+++ b/tests/test_client_cursor_async.py
@@ -577,12 +577,14 @@ async def test_query_params_executemany(aconn):
 
 async def test_stream(aconn):
     cur = aconn.cursor()
-    with pytest.raises(psycopg.NotSupportedError):
-        async for rec in cur.stream(
-            "select i, '2021-01-01'::date + i from generate_series(1, %s) as i",
-            [2],
-        ):
-            pass
+    recs = []
+    async for rec in cur.stream(
+        "select i, '2021-01-01'::date + i from generate_series(1, %s) as i",
+        [2],
+    ):
+        recs.append(rec)
+
+    assert recs == [(1, dt.date(2021, 1, 2)), (2, dt.date(2021, 1, 3))]
 
 
 async def test_str(aconn):