Fixed #19665 -- Ensured proper stderr output for Command.run_from_argv

Thanks Stefan Koegl for the report and Simon Charette for the review.

django/core/management/base.py

@@ -221,9 +221,12 @@ class BaseCommand(object):
         try:
             self.execute(*args, **options.__dict__)
         except Exception as e:
+            # self.stderr is not guaranteed to be set here
+            stderr = getattr(self, 'stderr', OutputWrapper(sys.stderr, self.style.ERROR))
             if options.traceback:
-                self.stderr.write(traceback.format_exc())
-            self.stderr.write('%s: %s' % (e.__class__.__name__, e))
+                stderr.write(traceback.format_exc())
+            else:
+                stderr.write('%s: %s' % (e.__class__.__name__, e))
             sys.exit(1)
 
     def execute(self, *args, **options):

tests/regressiontests/admin_scripts/tests.py

@@ -16,11 +16,13 @@ import codecs
 
 from django import conf, bin, get_version
 from django.conf import settings
+from django.core.management import BaseCommand
 from django.db import connection
 from django.test.simple import DjangoTestSuiteRunner
 from django.utils import unittest
 from django.utils.encoding import force_str, force_text
 from django.utils._os import upath
+from django.utils.six import StringIO
 from django.test import LiveServerTestCase
 
 test_dir = os.path.dirname(os.path.dirname(upath(__file__)))
@@ -1279,6 +1281,31 @@ class CommandTypes(AdminScriptTestCase):
         self.assertNoOutput(err)
         self.assertOutput(out, "EXECUTE:BaseCommand labels=('testlabel',), options=[('option_a', 'x'), ('option_b', 'y'), ('option_c', '3'), ('pythonpath', None), ('settings', None), ('traceback', None), ('verbosity', '1')]")
 
+    def test_base_run_from_argv(self):
+        """
+        Test run_from_argv properly terminates even with custom execute() (#19665)
+        Also test proper traceback display.
+        """
+        command = BaseCommand()
+        command.execute = lambda args: args  # This will trigger TypeError
+
+        old_stderr = sys.stderr
+        sys.stderr = err = StringIO()
+        try:
+            with self.assertRaises(SystemExit):
+                command.run_from_argv(['', ''])
+            err_message = err.getvalue()
+            self.assertNotIn("Traceback", err_message)
+            self.assertIn("TypeError", err_message)
+
+            with self.assertRaises(SystemExit):
+                command.run_from_argv(['', '', '--traceback'])
+            err_message = err.getvalue()
+            self.assertIn("Traceback (most recent call last)", err_message)
+            self.assertIn("TypeError", err_message)
+        finally:
+            sys.stderr = old_stderr
+
     def test_noargs(self):
         "NoArg Commands can be executed"
         args = ['noargs_command']