gh-87868: Sort and remove duplicates in getenvironment()

Lib/test/test_subprocess.py

@@ -786,6 +786,19 @@ def test_env(self):
  stdout, stderr = p.communicate()
  self.assertEqual(stdout, b"orange")
 
+ @unittest.skipUnless(sys.platform == "win32", "Windows only issue")
+ def test_win32_duplicate_envs(self):
+ newenv = os.environ.copy()
+ newenv["fRUit"] = "cherry"
+ newenv["fruit"] = "lemon"
+ newenv["FRUIT"] = "orange"
+ newenv["frUit"] = "banana"
+ with subprocess.Popen(["CMD", "/c", "SET", "fruit"],
+ stdout=subprocess.PIPE,
+ env=newenv) as p:
+ stdout, _ = p.communicate()
+ self.assertEqual(stdout.strip(), b"frUit=banana")
+
  # Windows requires at least the SYSTEMROOT environment variable to start
  # Python
  @unittest.skipIf(sys.platform == 'win32',
@@ -817,6 +830,17 @@ def is_env_var_to_ignore(n):
  if not is_env_var_to_ignore(k)]
  self.assertEqual(child_env_names, [])
 
+ def test_one_environment_variable(self):
+ newenv ={'fruit': 'orange'}
+ cmd = [sys.executable, '-c',
+ 'import sys,os;'
+ 'sys.stdout.write("fruit="+os.getenv("fruit"))']
+ if sys.platform == "win32":
+ cmd = ["CMD", "/c", "SET", "fruit"]
+ with subprocess.Popen(cmd, stdout=subprocess.PIPE, env=newenv) as p:
+ stdout, _ = p.communicate()
+ self.assertTrue(stdout.startswith(b"fruit=orange"))
+
  def test_invalid_cmd(self):
  # null character in the command name
  cmd = sys.executable + '\0'
@@ -857,6 +881,19 @@ def test_invalid_env(self):
  stdout, stderr = p.communicate()
  self.assertEqual(stdout, b"orange=lemon")
 
+ @unittest.skipUnless(sys.platform == "win32", "Windows only issue")
+ def test_win32_invalid_env(self):
+ # '=' in the environment variable name
+ newenv = os.environ.copy()
+ newenv["FRUIT=VEGETABLE"] = "cabbage"
+ with self.assertRaises(ValueError):
+ subprocess.Popen(ZERO_RETURN_CMD, env=newenv)
+
+ newenv = os.environ.copy()
+ newenv["==FRUIT"] = "cabbage"
+ with self.assertRaises(ValueError):
+ subprocess.Popen(ZERO_RETURN_CMD, env=newenv)
+
  def test_communicate_stdin(self):
  p = subprocess.Popen([sys.executable, "-c",
  'import sys;'

Misc/NEWS.d/next/Windows/2023-03-15-23-53-45.gh-issue-87868.4C36oQ.rst

@@ -0,0 +1,2 @@
+Correctly sort and remove duplicate environment variables in
+:py:func:`!_winapi.CreateProcess`.

Modules/_winapi.c

@@ -774,12 +774,157 @@ gethandle(PyObject* obj, const char* name)
  return ret;
 }
 
+static PyObject *
+sortenvironmentkey(PyObject *module, PyObject *item)
+{
+ return _winapi_LCMapStringEx_impl(NULL, LOCALE_NAME_INVARIANT,
+ LCMAP_UPPERCASE, item);
+}
+
+static PyMethodDef sortenvironmentkey_def ={
+ "sortenvironmentkey", _PyCFunction_CAST(sortenvironmentkey), METH_O, "",
+};
+
+static int
+sort_environment_keys(PyObject *keys)
+{
+ PyObject *keyfunc = PyCFunction_New(&sortenvironmentkey_def, NULL);
+ if (keyfunc == NULL){
+ return -1;
+ }
+ PyObject *kwnames = Py_BuildValue("(s)", "key");
+ if (kwnames == NULL){
+ Py_DECREF(keyfunc);
+ return -1;
+ }
+ PyObject *args[] ={keys, keyfunc };
+ PyObject *ret = PyObject_VectorcallMethod(&_Py_ID(sort), args, 1, kwnames);
+ Py_DECREF(keyfunc);
+ Py_DECREF(kwnames);
+ if (ret == NULL){
+ return -1;
+ }
+ Py_DECREF(ret);
+
+ return 0;
+}
+
+static int
+compare_string_ordinal(PyObject *str1, PyObject *str2, int *result)
+{
+ wchar_t *s1 = PyUnicode_AsWideCharString(str1, NULL);
+ if (s1 == NULL){
+ return -1;
+ }
+ wchar_t *s2 = PyUnicode_AsWideCharString(str2, NULL);
+ if (s2 == NULL){
+ PyMem_Free(s1);
+ return -1;
+ }
+ *result = CompareStringOrdinal(s1, -1, s2, -1, TRUE);
+ PyMem_Free(s1);
+ PyMem_Free(s2);
+ return 0;
+}
+
+static PyObject *
+dedup_environment_keys(PyObject *keys)
+{
+ PyObject *result = PyList_New(0);
+ if (result == NULL){
+ return NULL;
+ }
+
+ // Iterate over the pre-ordered keys, check whether the current key is equal
+ // to the next key (ignoring case), if different, insert the current value
+ // into the result list. If they are equal, do nothing because we always
+ // want to keep the last inserted one.
+ for (Py_ssize_t i = 0; i < PyList_GET_SIZE(keys); i++){
+ PyObject *key = PyList_GET_ITEM(keys, i);
+
+ // The last key will always be kept.
+ if (i + 1 == PyList_GET_SIZE(keys)){
+ if (PyList_Append(result, key) < 0){
+ Py_DECREF(result);
+ return NULL;
+ }
+ continue;
+ }
+
+ PyObject *next_key = PyList_GET_ITEM(keys, i + 1);
+ int compare_result;
+ if (compare_string_ordinal(key, next_key, &compare_result) < 0){
+ Py_DECREF(result);
+ return NULL;
+ }
+ if (compare_result == CSTR_EQUAL){
+ continue;
+ }
+ if (PyList_Append(result, key) < 0){
+ Py_DECREF(result);
+ return NULL;
+ }
+ }
+
+ return result;
+}
+
+static PyObject *
+normalize_environment(PyObject *environment)
+{
+ PyObject *keys = PyMapping_Keys(environment);
+ if (keys == NULL){
+ return NULL;
+ }
+
+ if (sort_environment_keys(keys) < 0){
+ Py_DECREF(keys);
+ return NULL;
+ }
+
+ PyObject *normalized_keys = dedup_environment_keys(keys);
+ Py_DECREF(keys);
+ if (normalized_keys == NULL){
+ return NULL;
+ }
+
+ PyObject *result = PyDict_New();
+ if (result == NULL){
+ Py_DECREF(normalized_keys);
+ return NULL;
+ }
+
+ for (int i = 0; i < PyList_GET_SIZE(normalized_keys); i++){
+ PyObject *key = PyList_GET_ITEM(normalized_keys, i);
+ PyObject *value = PyObject_GetItem(environment, key);
+ if (value == NULL){
+ Py_DECREF(normalized_keys);
+ Py_DECREF(result);
+ return NULL;
+ }
+
+ int ret = PyObject_SetItem(result, key, value);
+ Py_DECREF(value);
+ if (ret < 0){
+ Py_DECREF(normalized_keys);
+ Py_DECREF(result);
+ return NULL;
+ }
+ }
+
+ Py_DECREF(normalized_keys);
+
+ return result;
+}
+
 static wchar_t *
 getenvironment(PyObject* environment)
 {
  Py_ssize_t i, envsize, totalsize;
  wchar_t *buffer = NULL, *p, *end;
- PyObject *keys, *values;
+ PyObject *normalized_environment = NULL;
+ PyObject *keys = NULL;
+ PyObject *values = NULL;
 
  /* convert environment dictionary to windows environment string */
  if (! PyMapping_Check(environment)){
@@ -788,11 +933,16 @@ getenvironment(PyObject* environment)
  return NULL;
  }
 
-keys = PyMapping_Keys(environment);
- if (!keys){
+normalized_environment = normalize_environment(environment);
+ if (normalize_environment == NULL){
  return NULL;
  }
- values = PyMapping_Values(environment);
+
+ keys = PyMapping_Keys(normalized_environment);
+ if (!keys){
+ goto error;
+ }
+ values = PyMapping_Values(normalized_environment);
  if (!values){
  goto error;
  }
@@ -884,6 +1034,7 @@ getenvironment(PyObject* environment)
 
 cleanup:
 error:
+ Py_XDECREF(normalized_environment);
  Py_XDECREF(keys);
  Py_XDECREF(values);
  return buffer;