Issue #21718: cursor.description is now available for queries using CTEs
According to PEP 249, cursor.description must be
available for any SELECT statements, such as those
that use CTEs.
Backported from https://github.com/ghaering/pysqlite/commit/f67fa9c898a4713850e16934046f0fe2cba8c44c
Additional test cases added by me.
diff --git a/Lib/sqlite3/test/types.py b/Lib/sqlite3/test/types.py
index 6667bc8..0b5b3e7 100644
--- a/Lib/sqlite3/test/types.py
+++ b/Lib/sqlite3/test/types.py
@@ -274,6 +274,45 @@
self.cur.execute("select * from test where 0 = 1")
self.assertEqual(self.cur.description[0][0], "x")
+ def CheckCursorDescriptionInsert(self):
+ self.cur.execute("insert into test values (1)")
+ self.assertIsNone(self.cur.description)
+
+
+@unittest.skipIf(sqlite.sqlite_version_info < (3, 8, 3), "CTEs not supported")
+class CommonTableExpressionTests(unittest.TestCase):
+
+ def setUp(self):
+ self.con = sqlite.connect(":memory:")
+ self.cur = self.con.cursor()
+ self.cur.execute("create table test(x foo)")
+
+ def tearDown(self):
+ self.cur.close()
+ self.con.close()
+
+ def CheckCursorDescriptionCTESimple(self):
+ self.cur.execute("with one as (select 1) select * from one")
+ self.assertIsNotNone(self.cur.description)
+ self.assertEqual(self.cur.description[0][0], "1")
+
+ def CheckCursorDescriptionCTESMultipleColumns(self):
+ self.cur.execute("insert into test values(1)")
+ self.cur.execute("insert into test values(2)")
+ self.cur.execute("with testCTE as (select * from test) select * from testCTE")
+ self.assertIsNotNone(self.cur.description)
+ self.assertEqual(self.cur.description[0][0], "x")
+
+ def CheckCursorDescriptionCTE(self):
+ self.cur.execute("insert into test values (1)")
+ self.cur.execute("with bar as (select * from test) select * from test where x = 1")
+ self.assertIsNotNone(self.cur.description)
+ self.assertEqual(self.cur.description[0][0], "x")
+ self.cur.execute("with bar as (select * from test) select * from test where x = 2")
+ self.assertIsNotNone(self.cur.description)
+ self.assertEqual(self.cur.description[0][0], "x")
+
+
class ObjectAdaptationTests(unittest.TestCase):
def cast(obj):
return float(obj)
@@ -372,7 +411,8 @@
adaptation_suite = unittest.makeSuite(ObjectAdaptationTests, "Check")
bin_suite = unittest.makeSuite(BinaryConverterTests, "Check")
date_suite = unittest.makeSuite(DateTimeTests, "Check")
- return unittest.TestSuite((sqlite_type_suite, decltypes_type_suite, colnames_type_suite, adaptation_suite, bin_suite, date_suite))
+ cte_suite = unittest.makeSuite(CommonTableExpressionTests, "Check")
+ return unittest.TestSuite((sqlite_type_suite, decltypes_type_suite, colnames_type_suite, adaptation_suite, bin_suite, date_suite, cte_suite))
def test():
runner = unittest.TextTestRunner()
diff --git a/Misc/NEWS b/Misc/NEWS
index 36af974..54cae1d 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -46,6 +46,8 @@
Library
-------
+- Issue #21718: cursor.description is now available for queries using CTEs.
+
- Issue #2466: posixpath.ismount now correctly recognizes mount points which
the user does not have permission to access.
diff --git a/Modules/_sqlite/cursor.c b/Modules/_sqlite/cursor.c
index 300da28..e1676de 100644
--- a/Modules/_sqlite/cursor.c
+++ b/Modules/_sqlite/cursor.c
@@ -646,12 +646,11 @@
goto error;
}
- if (rc == SQLITE_ROW || (rc == SQLITE_DONE && statement_type == STATEMENT_SELECT)) {
- if (self->description == Py_None) {
- Py_BEGIN_ALLOW_THREADS
- numcols = sqlite3_column_count(self->statement->st);
- Py_END_ALLOW_THREADS
-
+ if (rc == SQLITE_ROW || rc == SQLITE_DONE) {
+ Py_BEGIN_ALLOW_THREADS
+ numcols = sqlite3_column_count(self->statement->st);
+ Py_END_ALLOW_THREADS
+ if (self->description == Py_None && numcols > 0) {
Py_SETREF(self->description, PyTuple_New(numcols));
if (!self->description) {
goto error;