Fix assertion failure with PL/Python exceptions

michaelpq · michaelpq · commit af5b3c3d1eae · 2023-09-19T08:31:06.000+09:00
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 2bd78eb, 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
@@ -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 plpython3u;
+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
@@ -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 plpython3u;
+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
@@ -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
@@ -344,3 +344,14 @@ $$ LANGUAGE plpython3u;
 \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 plpython3u;
+
+SELECT python_error_detail();

Original file line number	Diff line number	Diff line change
`@@ -103,9 +103,6 @@ PLy_elog_impl(int elevel, const char *fmt,...)`
`103`	`103`	`}`
`104`	`104`	`primary = emsg.data;`
`105`	`105`
`106`		`- /* Since we have a format string, we cannot have a SPI detail. */`
`107`		`- Assert(detail == NULL);`
`108`		`-`
`109`	`106`	`/* If there's an exception message, it goes in the detail. */`
`110`	`107`	`if (xmsg)`
`111`	`108`	`detail = xmsg;`