From: Daniele Varrazzo <daniele.varrazzo@gmail.com>
Date: Wed, 8 Jan 2025 00:33:52 +0000 (+0100)
Subject: fix(c): don't clobber an error from the server with a server disconnection
X-Git-Tag: 3.2.4~6^2~2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a8262ec89e11192379b43fd28fc288a4cd251b37;p=thirdparty%2Fpsycopg.git

fix(c): don't clobber an error from the server with a server disconnection

Instead of raising the exception here, return the result and let the
caller handle the exception. This might make code paths more uniform and
helps the C implementation, because we actually never call
`error_from_result()` in the Cython code.
---

diff --git a/psycopg/psycopg/generators.py b/psycopg/psycopg/generators.py
index 67a31878d..44e9f4e99 100644
--- a/psycopg/psycopg/generators.py
+++ b/psycopg/psycopg/generators.py
@@ -180,13 +180,13 @@ def _fetch_many(pgconn: PGconn) -> PQGen[list[PGresult]]:
         try:
             res = yield from _fetch(pgconn)
         except e.DatabaseError:
-            # What might have happened here is that a previuos error
-            # disconnected the connection, for example a idle in transaction
-            # timeout. Check if we had received an error before, and raise it
-            # as exception, because it should contain more details. See #988.
-            for res in results:
-                if res.status == FATAL_ERROR:
-                    raise e.error_from_result(res, encoding=pgconn._encoding) from None
+            # What might have happened here is that a previuos error disconnected
+            # the connection, for example a idle in transaction timeout.
+            # Check if we had received an error before: if that's the case
+            # just exit the loop. Our callers will handle this error and raise
+            # it as an exception.
+            if any(res.status == FATAL_ERROR for res in results):
+                break
             else:
                 raise
 
diff --git a/psycopg_c/psycopg_c/_psycopg/generators.pyx b/psycopg_c/psycopg_c/_psycopg/generators.pyx
index a908577c2..c280d1389 100644
--- a/psycopg_c/psycopg_c/_psycopg/generators.pyx
+++ b/psycopg_c/psycopg_c/_psycopg/generators.pyx
@@ -173,9 +173,21 @@ def fetch_many(pq.PGconn pgconn) -> PQGen[list[PGresult]]:
     cdef libpq.PGresult *pgres
 
     while True:
-        result = yield from fetch(pgconn)
+        try:
+            result = yield from fetch(pgconn)
+        except e.DatabaseError:
+            # What might have happened here is that a previuos error
+            # disconnected the connection, for example a idle in transaction
+            # timeout. Check if we had received an error before, and raise it
+            # as exception, because it should contain more details. See #988.
+            if any(result.status == libpq.PGRES_FATAL_ERROR for res in results):
+                break
+            else:
+                raise
+
         if result is None:
             break
+
         results.append(result)
         pgres = result._pgresult_ptr