Content-Type: multipart/mixed; boundary="------------c2WkN9NRhe6YOZcpvZQeJdSf"
Message-ID: <9fa9c154-d084-07de-8224-aab7fc8a119e@gmail.com>
Date: Fri, 15 Sep 2023 20:00:00 +0300
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101
 Thunderbird/102.4.2
Subject: Re: BUG #18070: Assertion failed when processing error from plpy's
 iterator
Content-Language: en-US
To: pgsql-bugs@lists.postgresql.org
References: <18070-ab9c171cbf4ebb0f@postgresql.org>
From: Alexander Lakhin <exclusion@gmail.com>
In-Reply-To: <18070-ab9c171cbf4ebb0f@postgresql.org>
Archived-At: 
 <https://www.postgresql.org/message-id/9fa9c154-d084-07de-8224-aab7fc8a119e%40gmail.com>
Precedence: bulk

This is a multi-part message in MIME format.
--------------c2WkN9NRhe6YOZcpvZQeJdSf
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit

25.08.2023 17:00, PG Bug reporting form wrote:
> The following bug has been logged on the website:
>
> Bug reference:      18070
> ...
> It looks like the following coding in PLy_elog_impl():
> 		/* Since we have a format string, we cannot have a SPI detail. */
> 		Assert(detail == NULL);
>
> 		/* If there's an exception message, it goes in the detail. */
> 		if (xmsg)
> 			detail = xmsg;
>
> doesn't expect to process a call PLy_elog(LEVEL, "message") when some (SPI)
> error occurred before the call.
>

Please look at the patch attached, which removes the Assert and changes
the detail message e.g. , for the query:
CREATE EXTENSION plpython3u;
CREATE TYPE tst AS (t text);
CREATE FUNCTION pyfunc() RETURNS SETOF text AS $$
   plan = plpy.prepare("SELECT * FROM tst", ["text"])
   for row in plpy.cursor(plan, ["w"]):
     yield row[0]
$$ LANGUAGE plpython3u;

SELECT pyfunc();

From:
ERROR:  error fetching next item from iterator
LINE 1: SELECT * FROM tst
                       ^
DETAIL:  spiexceptions.WrongObjectType: cannot open relation "tst"
QUERY:  SELECT * FROM tst
CONTEXT:  Traceback (most recent call last):
PL/Python function "pyfunc"

To:
ERROR:  error fetching next item from iterator
LINE 1: SELECT * FROM tst
                       ^
DETAIL:  This operation is not supported for composite types.
QUERY:  SELECT * FROM tst
CONTEXT:  Traceback (most recent call last):
PL/Python function "pyfunc"

Best regards,
Alexander
--------------c2WkN9NRhe6YOZcpvZQeJdSf
Content-Type: text/x-patch; charset=UTF-8; name="fix-plpy_elog.patch"
Content-Disposition: attachment; filename="fix-plpy_elog.patch"
Content-Transfer-Encoding: base64
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--------------c2WkN9NRhe6YOZcpvZQeJdSf--