bpo-39395: putenv() and unsetenv() always available (GH-18135)

The os.putenv() and os.unsetenv() functions are now always available.

On non-Windows platforms, Python now requires setenv() and unsetenv()
functions to build.

Remove putenv_dict from posixmodule.c: it's not longer needed.

1 files changed, 6 insertions, 26 deletions

diff --git a/Lib/os.py b/Lib/os.py
index ca418ed..7ae1026 100644
--- a/Lib/os.py
+++ b/Lib/os.py
@@ -654,17 +654,15 @@ def get_exec_path(env=None):
     return path_list.split(pathsep)
 
 
-# Change environ to automatically call putenv(), unsetenv if they exist.
+# Change environ to automatically call putenv() and unsetenv()
 from _collections_abc import MutableMapping
 
 class _Environ(MutableMapping):
-    def __init__(self, data, encodekey, decodekey, encodevalue, decodevalue, putenv, unsetenv):
+    def __init__(self, data, encodekey, decodekey, encodevalue, decodevalue):
         self.encodekey = encodekey
         self.decodekey = decodekey
         self.encodevalue = encodevalue
         self.decodevalue = decodevalue
-        self.putenv = putenv
-        self.unsetenv = unsetenv
         self._data = data
 
     def __getitem__(self, key):
@@ -678,12 +676,12 @@ class _Environ(MutableMapping):
     def __setitem__(self, key, value):
         key = self.encodekey(key)
         value = self.encodevalue(value)
-        self.putenv(key, value)
+        putenv(key, value)
         self._data[key] = value
 
     def __delitem__(self, key):
         encodedkey = self.encodekey(key)
-        self.unsetenv(encodedkey)
+        unsetenv(encodedkey)
         try:
             del self._data[encodedkey]
         except KeyError:
@@ -712,22 +710,6 @@ class _Environ(MutableMapping):
             self[key] = value
         return self[key]
 
-try:
-    _putenv = putenv
-except NameError:
-    _putenv = lambda key, value: None
-else:
-    if "putenv" not in __all__:
-        __all__.append("putenv")
-
-try:
-    _unsetenv = unsetenv
-except NameError:
-    _unsetenv = lambda key: _putenv(key, "")
-else:
-    if "unsetenv" not in __all__:
-        __all__.append("unsetenv")
-
 def _createenviron():
     if name == 'nt':
         # Where Env Var Names Must Be UPPERCASE
@@ -755,8 +737,7 @@ def _createenviron():
         data = environ
     return _Environ(data,
         encodekey, decode,
-        encode, decode,
-        _putenv, _unsetenv)
+        encode, decode)
 
 # unicode environ
 environ = _createenviron()
@@ -781,8 +762,7 @@ if supports_bytes_environ:
     # bytes environ
     environb = _Environ(environ._data,
         _check_bytes, bytes,
-        _check_bytes, bytes,
-        _putenv, _unsetenv)
+        _check_bytes, bytes)
     del _check_bytes
 
     def getenvb(key, default=None):