Issue #18338: `python --version` now prints version string to stdout, and

not to stderr.  Patch by Berker Peksag and Michael Dickens.

Lib/test/test_cmd_line.py

@@ -41,8 +41,10 @@ class CmdLineTest(unittest.TestCase):
 
     def test_version(self):
         version = ('Python %d.%d' % sys.version_info[:2]).encode("ascii")
-        rc, out, err = assert_python_ok('-V')
-        self.assertTrue(err.startswith(version))
+        for switch in '-V', '--version':
+            rc, out, err = assert_python_ok(switch)
+            self.assertFalse(err.startswith(version))
+            self.assertTrue(out.startswith(version))
 
     def test_verbose(self):
         # -v causes imports to write to stderr.  If the write to

Misc/NEWS

@@ -10,6 +10,9 @@ What's New in Python 3.4.0 Alpha 1?
 Core and Builtins
 -----------------
 
+- Issue #18338: `python --version` now prints version string to stdout, and
+  not to stderr.  Patch by Berker Peksag and Michael Dickens.
+
 - Issue #18426: Fix NULL pointer dereference in C extension import when
   PyModule_GetDef() returns an error.
 

Modules/main.c

@@ -500,7 +500,7 @@ Py_Main(int argc, wchar_t **argv)
         return usage(0, argv[0]);
 
     if (version) {
-        fprintf(stderr, "Python %s\n", PY_VERSION);
+        printf("Python %s\n", PY_VERSION);
         return 0;
     }