Issue #8202: Set sys.argv[0] to -m rather than -c while searching for the...

Issue #8202: Set sys.argv[0] to -m rather than -c while searching for the module to execute. Also updates all the cmd_line_script tests to validate the setting of sys.path[0] and the current working directory

Doc/using/cmdline.rst

@@ -95,8 +95,9 @@ source.
       file is not available.
 
    If this option is given, the first element of :data:`sys.argv` will be the
-   full path to the module file. As with the :option:`-c` option, the current
-   directory will be added to the start of :data:`sys.path`.
+   full path to the module file (while the module file is being located, the
+   first element will be set to ``"-m"``). As with the :option:`-c` option,
+   the current directory will be added to the start of :data:`sys.path`.
 
    Many standard library modules contain code that is invoked on their execution
    as a script.  An example is the :mod:`timeit` module::

Lib/test/script_helper.py

@@ -86,9 +86,9 @@ def make_zip_script(zip_dir, zip_basename, script_name, name_in_zip=None):
     #    zip_file.close()
     return zip_name, os.path.join(zip_name, name_in_zip)
 
-def make_pkg(pkg_dir):
+def make_pkg(pkg_dir, init_source=''):
     os.mkdir(pkg_dir)
-    make_script(pkg_dir, '__init__', '')
+    make_script(pkg_dir, '__init__', init_source)
 
 def make_zip_pkg(zip_dir, zip_basename, pkg_name, script_basename,
                  source, depth=1, compiled=False):

Lib/test/support.py

@@ -419,21 +419,32 @@ elif sys.platform != 'darwin':
 SAVEDCWD = os.getcwd()
 
 @contextlib.contextmanager
-def temp_cwd(name='tempcwd', quiet=False):
+def temp_cwd(name='tempcwd', quiet=False, path=None):
     """
-    Context manager that creates a temporary directory and set it as CWD.
+    Context manager that temporarily changes the CWD.
 
-    The new CWD is created in the current directory and it's named *name*.
-    If *quiet* is False (default) and it's not possible to create or change
-    the CWD, an error is raised.  If it's True, only a warning is raised
-    and the original CWD is used.
+    An existing path may be provided as *path*, in which case this
+    function makes no changes to the file system.
+
+    Otherwise, the new CWD is created in the current directory and it's
+    named *name*. If *quiet* is False (default) and it's not possible to
+    create or change the CWD, an error is raised.  If it's True, only a
+    warning is raised and the original CWD is used.
     """
     saved_dir = os.getcwd()
     is_temporary = False
+    if path is None:
+        path = name
+        try:
+            os.mkdir(name)
+            is_temporary = True
+        except OSError:
+            if not quiet:
+                raise
+            warnings.warn('tests may fail, unable to create temp CWD ' + name,
+                          RuntimeWarning, stacklevel=3)
     try:
-        os.mkdir(name)
-        os.chdir(name)
-        is_temporary = True
+        os.chdir(path)
     except OSError:
         if not quiet:
             raise

Lib/test/test_cmd_line.py

 # Tests invocation of the interpreter with various command line arguments
-# All tests are executed with environment variables ignored
+# Most tests are executed with environment variables ignored
 # See test_cmd_line_script.py for testing of script execution
 
 import test.support, unittest
@@ -7,10 +7,6 @@ import os
 import sys
 from test.script_helper import spawn_python, kill_python, python_exit_code
 
-# XXX (ncoghlan): there are assorted gratuitous inconsistencies between the
-# support code in the Py3k version and the 2.x version that unnecessarily
-# complicate test suite merges. See issue 7331
-
 # spawn_python normally enforces use of -E to avoid environmental effects
 # but one test checks PYTHONPATH behaviour explicitly
 # XXX (ncoghlan): Give script_helper.spawn_python an option to switch

Misc/NEWS

@@ -12,6 +12,9 @@ What's New in Python 3.2 Alpha 2?
 Core and Builtins
 -----------------
 
+- Issue #8202: sys.argv[0] is now set to '-m' instead of '-c' when searching
+  for the module file to be executed with the -m command  line option.
+
 - Issue #9599: Create PySys_FormatStdout() and PySys_FormatStderr() functions
   to write a message formatted by PyUnicode_FromFormatV() to sys.stdout and
   sys.stderr.

Modules/main.c

@@ -604,10 +604,9 @@ Py_Main(int argc, wchar_t **argv)
     }
 
     if (module != NULL) {
-        /* Backup _PyOS_optind and force sys.argv[0] = '-c'
-           so that PySys_SetArgv correctly sets sys.path[0] to ''*/
+        /* Backup _PyOS_optind and force sys.argv[0] = '-m'*/
         _PyOS_optind--;
-        argv[_PyOS_optind] = L"-c";
+        argv[_PyOS_optind] = L"-m";
     }
 
     PySys_SetArgv(argc-_PyOS_optind, argv+_PyOS_optind);

Python/sysmodule.c

@@ -1723,6 +1723,10 @@ _wrealpath(const wchar_t *path, wchar_t *resolved_path)
 }
 #endif
 
+#define _HAVE_SCRIPT_ARGUMENT(argc, argv) \
+  (argc > 0 && argv0 != NULL && \
+   wcscmp(argv0, L"-c") != 0 && wcscmp(argv0, L"-m") != 0)
+  
 void
 PySys_SetArgvEx(int argc, wchar_t **argv, int updatepath)
 {
@@ -1747,7 +1751,7 @@ PySys_SetArgvEx(int argc, wchar_t **argv, int updatepath)
         wchar_t link[MAXPATHLEN+1];
         wchar_t argv0copy[2*MAXPATHLEN+1];
         int nr = 0;
-        if (argc > 0 && argv0 != NULL && wcscmp(argv0, L"-c") != 0)
+        if (_HAVE_SCRIPT_ARGUMENT(argc, argv))
             nr = _Py_wreadlink(argv0, link, MAXPATHLEN);
         if (nr > 0) {
             /* It's a symlink */
@@ -1772,7 +1776,7 @@ PySys_SetArgvEx(int argc, wchar_t **argv, int updatepath)
         }
 #endif /* HAVE_READLINK */
 #if SEP == '\\' /* Special case for MS filename syntax */
-        if (argc > 0 && argv0 != NULL && wcscmp(argv0, L"-c") != 0) {
+        if (_HAVE_SCRIPT_ARGUMENT(argc, argv)) {
             wchar_t *q;
 #if defined(MS_WINDOWS) && !defined(MS_WINCE)
             /* This code here replaces the first element in argv with the full
@@ -1798,7 +1802,7 @@ PySys_SetArgvEx(int argc, wchar_t **argv, int updatepath)
             }
         }
 #else /* All other filename syntaxes */
-        if (argc > 0 && argv0 != NULL && wcscmp(argv0, L"-c") != 0) {
+        if (_HAVE_SCRIPT_ARGUMENT(argc, argv)) {
 #if defined(HAVE_REALPATH)
             if (_wrealpath(argv0, fullpath)) {
                 argv0 = fullpath;