Fix assertion failure with PL/Python exceptions

PLy_elog() was not able to handle correctly cases where a SPI called
failed, which would fill in a DETAIL string able to trigger an
assertion.  We may want to improve this infrastructure so as it is able
to provide any extra detail information provided by an error stack, but
this is left as a future improvement as it could impact existing error
stacks and any applications that depend on them.  For now, the assertion
is removed and a regression test is added to cover the case of a failure
with a detail string.

This problem exists since 2bd78eb8d51c, so backpatch all the way down
with tweaks to the regression tests output added where required.

Author: Alexander Lakhin
Discussion: https://postgr.es/m/18070-ab9c171cbf4ebb0f@postgresql.org
Backpatch-through: 11

diff --git a/src/pl/plpython/expected/plpython_error.out b/src/pl/plpython/expected/plpython_error.out
index b2f8fe83eb60f61b1999a9b9aa17c6ada19c26da..0f1bab13b6bf73f01b0b9977637eec1fdef1716f 100644 (file)
--- 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)
 
+/* test error logged with an underlying exception that includes a detail
+ * string (bug #18070).
+ */
+CREATE FUNCTION python_error_detail() RETURNS SETOF text AS $$
+  plan = plpy.prepare("SELECT to_date('xy', 'DD') d")
+  for row in plpy.cursor(plan):
+    yield row['d']
+$$ LANGUAGE plpythonu;
+SELECT python_error_detail();
+ERROR:  error fetching next item from iterator
+DETAIL:  spiexceptions.InvalidDatetimeFormat: invalid value "xy" 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/plpython/expected/plpython_error_5.out
index bc66ab553400fced4d9fa835bb6e531c6671bae9..0e67b5a57510fcfb3823b480ff31533519104c58 100644 (file)
--- 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)
 
+/* test error logged with an underlying exception that includes a detail
+ * string (bug #18070).
+ */
+CREATE FUNCTION python_error_detail() RETURNS SETOF text AS $$
+  plan = plpy.prepare("SELECT to_date('xy', 'DD') d")
+  for row in plpy.cursor(plan):
+    yield row['d']
+$$ LANGUAGE plpythonu;
+SELECT python_error_detail();
+ERROR:  error fetching next item from iterator
+DETAIL:  spiexceptions.InvalidDatetimeFormat: invalid value "xy" 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 224b8836fba90011a0f69a73efafb383c1817c15..9b5b3bed2f5053b1036ce6d5aa42284a4c784dde 100644 (file)
--- 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 = emsg.data;
 
-       /* 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;

diff --git a/src/pl/plpython/sql/plpython_error.sql b/src/pl/plpython/sql/plpython_error.sql
index 88d6936fd0dc8a2ccb755f84274bce15890226eb..8d86bf7d1e065a87d69604d50e8d389f982ed9d1 100644 (file)
--- a/src/pl/plpython/sql/plpython_error.sql
+++ b/src/pl/plpython/sql/plpython_error.sql
@@ -344,3 +344,14 @@ $$ LANGUAGE plpythonu;
 \set SHOW_CONTEXT always
 
 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 $$
+  plan = plpy.prepare("SELECT to_date('xy', 'DD') d")
+  for row in plpy.cursor(plan):
+    yield row['d']
+$$ LANGUAGE plpythonu;
+
+SELECT python_error_detail();