fix non-year directive error; add supporting tests

Author: jyalim

Lib/_strptime.py

@@ -471,7 +471,7 @@ def pattern(self, format):
         def repl(m):
             directive = m.group()[1:] # exclude `%` symbol
             match directive:
-                case 'Y' | 'y' | 'G':
+                case 'Y' | 'y' | 'G' | 'C':
                     nonlocal year_in_format
                     year_in_format = True
                 case 'd':

Lib/test/datetimetester.py

@@ -2249,6 +2249,16 @@ def test_strptime_C_y_format(self):
                     self.theclass(int(y), 1, 1)
                 )
 
+    def test_strptime_C_d_format(self):
+        # verify %C provides a year directive, allowing days in format
+        for day_directive in ('%d', '%e'):
+            format_directive = f"%C-%m-{day_directive}"
+            with self.subTest(format_directive=format_directive):
+                self.assertEqual(
+                    self.theclass.strptime('20-05-22', format_directive),
+                    self.theclass(2000, 5, 22)
+                )
+
 #############################################################################
 # datetime tests
 

Lib/test/test_strptime.py

@@ -701,6 +701,16 @@ def test_strptime_C_y_format(self):
                     time.strptime(f'{year}-01-01', '%Y-%m-%d'),
                 )
 
+    def test_strptime_C_d_format(self):
+        # verify %C provides a year directive, allowing days in format
+        for day_directive in ('%d', '%e'):
+            format_directive = f"%C-%m-{day_directive}"
+            with self.subTest(format_directive=format_directive):
+                self.assertEqual(
+                    time.strptime('20-05-22', format_directive),
+                    time.strptime(f'2000-05-22', '%Y-%m-%d'),
+                )
+
 class Strptime12AMPMTests(unittest.TestCase):
     """Test a _strptime regression in '%I %p' at 12 noon (12 PM)"""