Feedback-ID: i0fe9450f:Fastmail
Date: Sun, 17 Sep 2023 10:50:36 +0900
From: Michael Paquier <michael@paquier.xyz>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Alexander Lakhin <exclusion@gmail.com>, pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #18070: Assertion failed when processing error from plpy's
 iterator
Message-ID: <ZQZbbPA7NC5A0f4i@paquier.xyz>
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 <3920993.1694874885@sss.pgh.pa.us>
 <5eba3ea5-ae13-aab2-35d6-cd3e58dab08b@gmail.com>
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On Sat, Sep 16, 2023 at 08:02:03PM -0400, Tom Lane wrote:
> +1.  Not very sure what we want to change this to in HEAD, but
> I wouldn't backpatch a behavioral change here.

Please find attached a proposal of patch for a backpatch, that applies
on HEAD.  The backpatch needs a few tweaks for alternate outputs, of
course, depending on the version of python.

Any thoughts?
--
Michael

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diff --git a/src/pl/plpython/expected/plpython_error.out b/src/pl/plpython/=
expected/plpython_error.out
index 9af7ea7292..77819cb416 100644
--- a/src/pl/plpython/expected/plpython_error.out
+++ b/src/pl/plpython/expected/plpython_error.out
@@ -445,3 +445,16 @@ PL/Python function "notice_outerfunc"
                 1
 (1 row)
=20
+/* test error logged with an underlying exception that includes a detail
+ * string (bug #18070).
+ */
+CREATE FUNCTION python_error_detail() RETURNS SETOF text AS $$
+  plan =3D plpy.prepare("SELECT to_date('DD', 'DD') d")
+  for row in plpy.cursor(plan):
+    yield row['d']
+$$ LANGUAGE plpython3u;
+SELECT python_error_detail();
+ERROR:  error fetching next item from iterator
+DETAIL:  spiexceptions.InvalidDatetimeFormat: invalid value "DD" for "DD"
+CONTEXT:  Traceback (most recent call last):
+PL/Python function "python_error_detail"
diff --git a/src/pl/plpython/expected/plpython_error_5.out b/src/pl/plpytho=
n/expected/plpython_error_5.out
index 7fe864a1a5..b1b4eaa375 100644
--- a/src/pl/plpython/expected/plpython_error_5.out
+++ b/src/pl/plpython/expected/plpython_error_5.out
@@ -445,3 +445,16 @@ PL/Python function "notice_outerfunc"
                 1
 (1 row)
=20
+/* test error logged with an underlying exception that includes a detail
+ * string (bug #18070).
+ */
+CREATE FUNCTION python_error_detail() RETURNS SETOF text AS $$
+  plan =3D plpy.prepare("SELECT to_date('DD', 'DD') d")
+  for row in plpy.cursor(plan):
+    yield row['d']
+$$ LANGUAGE plpython3u;
+SELECT python_error_detail();
+ERROR:  error fetching next item from iterator
+DETAIL:  spiexceptions.InvalidDatetimeFormat: invalid value "DD" for "DD"
+CONTEXT:  Traceback (most recent call last):
+PL/Python function "python_error_detail"
diff --git a/src/pl/plpython/plpy_elog.c b/src/pl/plpython/plpy_elog.c
index 7c627eacfb..70de5ba13d 100644
--- a/src/pl/plpython/plpy_elog.c
+++ b/src/pl/plpython/plpy_elog.c
@@ -103,9 +103,6 @@ PLy_elog_impl(int elevel, const char *fmt,...)
 		}
 		primary =3D emsg.data;
=20
-		/* Since we have a format string, we cannot have a SPI detail. */
-		Assert(detail =3D=3D NULL);
-
 		/* If there's an exception message, it goes in the detail. */
 		if (xmsg)
 			detail =3D xmsg;
diff --git a/src/pl/plpython/sql/plpython_error.sql b/src/pl/plpython/sql/p=
lpython_error.sql
index 11f14ec5a7..111f62eb27 100644
--- a/src/pl/plpython/sql/plpython_error.sql
+++ b/src/pl/plpython/sql/plpython_error.sql
@@ -344,3 +344,14 @@ $$ LANGUAGE plpython3u;
 \set SHOW_CONTEXT always
=20
 SELECT notice_outerfunc();
+
+/* test error logged with an underlying exception that includes a detail
+ * string (bug #18070).
+ */
+CREATE FUNCTION python_error_detail() RETURNS SETOF text AS $$
+  plan =3D plpy.prepare("SELECT to_date('DD', 'DD') d")
+  for row in plpy.cursor(plan):
+    yield row['d']
+$$ LANGUAGE plpython3u;
+
+SELECT python_error_detail();

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