From 47f5e97759879543edd8ee8ad9032ef67ec0567a Mon Sep 17 00:00:00 2001
From: Daniele Varrazzo <daniele.varrazzo@gmail.com>
Date: Wed, 5 Apr 2017 14:40:12 +0100
Subject: [PATCH 1/3] Added test to verify #410

The 'unknown error' happens on query.
---
 tests/test_green.py | 68 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 68 insertions(+)

diff --git a/tests/test_green.py b/tests/test_green.py
index 6d1571d4..b8fe4e13 100755
--- a/tests/test_green.py
+++ b/tests/test_green.py
@@ -112,6 +112,74 @@ class GreenTestCase(ConnectingTestCase):
         self.assertEqual(curs.fetchone()[0], 1)
 
 
+class CallbackErrorTestCase(ConnectingTestCase):
+    def setUp(self):
+        self._cb = psycopg2.extensions.get_wait_callback()
+        psycopg2.extensions.set_wait_callback(self.crappy_callback)
+        ConnectingTestCase.setUp(self)
+        self.to_error = None
+
+    def tearDown(self):
+        ConnectingTestCase.tearDown(self)
+        psycopg2.extensions.set_wait_callback(self._cb)
+
+    def crappy_callback(self, conn):
+        """green callback failing after `self.to_error` time it is called"""
+        import select
+        from psycopg2.extensions import POLL_OK, POLL_READ, POLL_WRITE
+
+        while 1:
+            if self.to_error is not None:
+                self.to_error -= 1
+                if self.to_error <= 0:
+                    raise ZeroDivisionError("I accidentally the connection")
+            try:
+                state = conn.poll()
+                if state == POLL_OK:
+                    break
+                elif state == POLL_READ:
+                    select.select([conn.fileno()], [], [])
+                elif state == POLL_WRITE:
+                    select.select([], [conn.fileno()], [])
+                else:
+                    raise conn.OperationalError("bad state from poll: %s" % state)
+            except KeyboardInterrupt:
+                conn.cancel()
+                # the loop will be broken by a server error
+                continue
+
+    def test_errors_on_connection(self):
+        # Test error propagation in the different stages of the connection
+        for i in range(100):
+            self.to_error = i
+            try:
+                self.connect()
+            except ZeroDivisionError:
+                pass
+            else:
+                # We managed to connect
+                return
+
+        self.fail("you should have had a success or an error by now")
+
+    def test_errors_on_query(self):
+        for i in range(100):
+            self.to_error = None
+            cnn = self.connect()
+            cur = cnn.cursor()
+            self.to_error = i
+            try:
+                cur.execute("select 1")
+                cur.fetchone()
+            except ZeroDivisionError:
+                pass
+            else:
+                # The query completed
+                return
+
+        self.fail("you should have had a success or an error by now")
+
+
 def test_suite():
     return unittest.TestLoader().loadTestsFromName(__name__)
 

From a66c34a6d098623617d675191a4c82f60de1d662 Mon Sep 17 00:00:00 2001
From: Daniele Varrazzo <daniele.varrazzo@gmail.com>
Date: Wed, 5 Apr 2017 14:05:59 +0100
Subject: [PATCH 2/3] Don't clobber a Python exception with an unknown error

Close #410
---
 NEWS             | 1 +
 psycopg/pqpath.c | 4 ++++
 2 files changed, 5 insertions(+)

diff --git a/NEWS b/NEWS
index 84be2015..a0399a15 100644
--- a/NEWS
+++ b/NEWS
@@ -7,6 +7,7 @@ What's new in psycopg 2.7.2
 - Fixed inconsistent state in externally closed connections
   (:tickets:`#263, #311, #443`). Was fixed in 2.6.2 but not included in
   2.7 by mistake.
+- Fixed Python exceptions propagation in green callback (:ticket:`#410`).
 - Don't display the password in `connection.dsn` when the connection
   string is specified as an URI (:ticket:`#528`).
 - Return objects with timezone parsing "infinity" :sql:`timestamptz`
diff --git a/psycopg/pqpath.c b/psycopg/pqpath.c
index f270ce8f..55720724 100644
--- a/psycopg/pqpath.c
+++ b/psycopg/pqpath.c
@@ -451,6 +451,10 @@ pq_complete_error(connectionObject *conn, PGresult **pgres, char **error)
     else {
         if (*error != NULL) {
             PyErr_SetString(OperationalError, *error);
+        } else if (PyErr_Occurred()) {
+            /* There was a Python error (e.g. in the callback). Don't clobber
+             * it with an unknown exception. (see #410) */
+            Dprintf("pq_complete_error: forwarding Python exception");
         } else {
             PyErr_SetString(OperationalError, "unknown error");
         }

From cd095ef0ee1dac13adb4d9a24260fe610e7a536f Mon Sep 17 00:00:00 2001
From: Daniele Varrazzo <daniele.varrazzo@gmail.com>
Date: Wed, 5 Apr 2017 14:43:00 +0100
Subject: [PATCH 3/3] Added test to verify callback errors in named cursors

They work fine.
---
 tests/test_green.py | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/tests/test_green.py b/tests/test_green.py
index b8fe4e13..8c1c20ce 100755
--- a/tests/test_green.py
+++ b/tests/test_green.py
@@ -179,6 +179,23 @@ class CallbackErrorTestCase(ConnectingTestCase):
 
         self.fail("you should have had a success or an error by now")
 
+    def test_errors_named_cursor(self):
+        for i in range(100):
+            self.to_error = None
+            cnn = self.connect()
+            cur = cnn.cursor('foo')
+            self.to_error = i
+            try:
+                cur.execute("select 1")
+                cur.fetchone()
+            except ZeroDivisionError:
+                pass
+            else:
+                # The query completed
+                return
+
+        self.fail("you should have had a success or an error by now")
+
 
 def test_suite():
     return unittest.TestLoader().loadTestsFromName(__name__)