gh-101714: Isolate _curses extension module

Include/py_curses.h

@@ -54,14 +54,15 @@
 extern "C" {
 #endif
 
-#define PyCurses_API_pointers 4
+#define PyCurses_API_pointers 5
 
 /* Type declarations */
 
 typedef struct {
     PyObject_HEAD
     WINDOW *win;
     char *encoding;
+    struct _curses_state *state;
 } PyCursesWindowObject;
 
 #define PyCursesWindow_Check(v) Py_IS_TYPE((v), &PyCursesWindow_Type)
@@ -78,9 +79,27 @@ typedef struct {
 static void **PyCurses_API;
 
 #define PyCursesWindow_Type (*_PyType_CAST(PyCurses_API[0]))
-#define PyCursesSetupTermCalled  {if (! ((int (*)(void))PyCurses_API[1]) () ) return NULL;}
-#define PyCursesInitialised      {if (! ((int (*)(void))PyCurses_API[2]) () ) return NULL;}
-#define PyCursesInitialisedColor {if (! ((int (*)(void))PyCurses_API[3]) () ) return NULL;}
+
+#define PyCursesSetupTermCalled \
+    if (!(*(int *)PyCurses_API[1])) { \
+        PyErr_SetString(PyCurses_API[4], \
+                        "must call (at least) setupterm() first"); \
+        return NULL; \
+    }
+
+#define PyCursesInitialised \
+    if (!(*(int *)PyCurses_API[2])) { \
+        PyErr_SetString(PyCurses_API[4], \
+                        "must call initscr() first"); \
+        return NULL; \
+    }
+
+#define PyCursesInitialisedColor \
+    if (!(*(int *)PyCurses_API[3])) { \
+        PyErr_SetString(PyCurses_API[4], \
+                        "must call start_color() first"); \
+        return NULL; \
+    }
 
 #define import_curses() \
     PyCurses_API = (void **)PyCapsule_Import(PyCurses_CAPSULE_NAME, 1);

Lib/test/test_curses.py

@@ -1,6 +1,7 @@
 import functools
 import inspect
 import os
+import pickle
 import string
 import sys
 import tempfile
@@ -1179,6 +1180,19 @@ def test_issue13051(self):
         # this may cause infinite recursion, leading to a RuntimeError
         box._insert_printable_char('a')
 
+    def test_window_non_instantiable(self):
+        # Ensure that '_curses.window' type in not directly instantiable
+        check_disallow_instantiation(self, curses.window)
+
+    def test_window_immutable(self):
+        with self.assertRaisesRegex(TypeError, "immutable"):
+            curses.window.foo = 123
+
+    def test_window_non_picklable(self):
+        win = curses.newwin(10, 10)
+        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+            self.assertRaises(TypeError, pickle.dumps, win, proto)
+
 
 class MiscTests(unittest.TestCase):
 

Misc/NEWS.d/next/Library/2023-05-22-23-24-58.gh-issue-101714.iw8L88.rst

@@ -0,0 +1 @@
+Isolate :mod:`!_curses` (apply :pep:`687`). Patch by Radislav Chugunov.