bpo-29240, bpo-32030: Py_Main() re-reads config if encoding changes (#4899)

bpo-29240, bpo-32030: If the encoding change (C locale coerced or
UTF-8 Mode changed), Py_Main() now reads again the configuration with
the new encoding.

Changes:

* Add _Py_UnixMain() called by main().
* Rename pymain_free_pymain() to pymain_clear_pymain(), it can now be
  called multipled times.
* Rename pymain_parse_cmdline_envvars() to pymain_read_conf().
* Py_Main() now clears orig_argc and orig_argv at exit.
* Remove argv_copy2, Py_Main() doesn't modify argv anymore. There is
  no need anymore to get two copies of the wchar_t** argv.
* _PyCoreConfig: add coerce_c_locale and coerce_c_locale_warn.
* Py_UTF8Mode is now initialized to -1.
* Locale coercion (PEP 538) now respects -I and -E options.

3 files changed, 30 insertions, 7 deletions

diff --git a/Lib/test/test_c_locale_coercion.py b/Lib/test/test_c_locale_coercion.py
index c0845d75a2..37dd834781 100644
--- a/Lib/test/test_c_locale_coercion.py
+++ b/Lib/test/test_c_locale_coercion.py
@@ -65,7 +65,7 @@ def _set_locale_in_subprocess(locale_name):
         # If there's no valid CODESET, we expect coercion to be skipped
         cmd_fmt += "; import sys; sys.exit(not locale.nl_langinfo(locale.CODESET))"
     cmd = cmd_fmt.format(locale_name)
-    result, py_cmd = run_python_until_end("-c", cmd, __isolated=True)
+    result, py_cmd = run_python_until_end("-c", cmd, PYTHONCOERCECLOCALE='')
     return result.rc == 0
 
 
@@ -131,7 +131,6 @@ class EncodingDetails(_EncodingDetails):
         """
         result, py_cmd = run_python_until_end(
             "-X", "utf8=0", "-c", cls.CHILD_PROCESS_SCRIPT,
-            __isolated=True,
             **env_vars
         )
         if not result.rc == 0:
@@ -236,6 +235,7 @@ class LocaleConfigurationTests(_LocaleHandlingTestCase):
             "LANG": "",
             "LC_CTYPE": "",
             "LC_ALL": "",
+            "PYTHONCOERCECLOCALE": "",
         }
         for env_var in ("LANG", "LC_CTYPE"):
             for locale_to_set in AVAILABLE_TARGETS:
@@ -294,6 +294,7 @@ class LocaleCoercionTests(_LocaleHandlingTestCase):
             "LANG": "",
             "LC_CTYPE": "",
             "LC_ALL": "",
+            "PYTHONCOERCECLOCALE": "",
         }
         base_var_dict.update(extra_vars)
         for env_var in ("LANG", "LC_CTYPE"):
diff --git a/Lib/test/test_cmd_line.py b/Lib/test/test_cmd_line.py
index 2b14c301c7..54ea3773a0 100644
--- a/Lib/test/test_cmd_line.py
+++ b/Lib/test/test_cmd_line.py
@@ -551,7 +551,7 @@ class CmdLineTest(unittest.TestCase):
         self.assertEqual(out, "True")
 
         # Warnings
-        code = ("import sys, warnings; "
+        code = ("import warnings; "
                 "print(' '.join('%s::%s' % (f[0], f[2].__name__) "
                                 "for f in warnings.filters))")
         if Py_DEBUG:
diff --git a/Lib/test/test_utf8_mode.py b/Lib/test/test_utf8_mode.py
index 275a6ea8ed..73d1bd424c 100644
--- a/Lib/test/test_utf8_mode.py
+++ b/Lib/test/test_utf8_mode.py
@@ -7,6 +7,7 @@ import os
 import sys
 import textwrap
 import unittest
+from test import support
 from test.support.script_helper import assert_python_ok, assert_python_failure
 
 
@@ -14,9 +15,11 @@ MS_WINDOWS = (sys.platform == 'win32')
 
 
 class UTF8ModeTests(unittest.TestCase):
-    # Override PYTHONUTF8 and PYTHONLEGACYWINDOWSFSENCODING environment
-    # variables by default
-    DEFAULT_ENV = {'PYTHONUTF8': '', 'PYTHONLEGACYWINDOWSFSENCODING': ''}
+    DEFAULT_ENV = {
+        'PYTHONUTF8': '',
+        'PYTHONLEGACYWINDOWSFSENCODING': '',
+        'PYTHONCOERCECLOCALE': '0',
+    }
 
     def posix_locale(self):
         loc = locale.setlocale(locale.LC_CTYPE, None)
@@ -53,7 +56,7 @@ class UTF8ModeTests(unittest.TestCase):
         self.assertEqual(out, '0')
 
         if MS_WINDOWS:
-            # PYTHONLEGACYWINDOWSFSENCODING disables the UTF-8
+            # PYTHONLEGACYWINDOWSFSENCODING disables the UTF-8 Mode
             # and has the priority over -X utf8
             out = self.get_output('-X', 'utf8', '-c', code,
                                   PYTHONLEGACYWINDOWSFSENCODING='1')
@@ -201,6 +204,25 @@ class UTF8ModeTests(unittest.TestCase):
         out = self.get_output('-X', 'utf8', '-c', code, LC_ALL='C')
         self.assertEqual(out, 'UTF-8 UTF-8')
 
+    @unittest.skipIf(MS_WINDOWS, 'test specific to Unix')
+    def test_cmd_line(self):
+        arg = 'h\xe9\u20ac'.encode('utf-8')
+        arg_utf8 = arg.decode('utf-8')
+        arg_ascii = arg.decode('ascii', 'surrogateescape')
+        code = 'import locale, sys; print("%s:%s" % (locale.getpreferredencoding(), ascii(sys.argv[1:])))'
+
+        def check(utf8_opt, expected, **kw):
+            out = self.get_output('-X', utf8_opt, '-c', code, arg, **kw)
+            args = out.partition(':')[2].rstrip()
+            self.assertEqual(args, ascii(expected), out)
+
+        check('utf8', [arg_utf8])
+        if sys.platform == 'darwin' or support.is_android:
+            c_arg = arg_utf8
+        else:
+            c_arg = arg_ascii
+        check('utf8=0', [c_arg], LC_ALL='C')
+
 
 if __name__ == "__main__":
     unittest.main()