gh-154055: Gate optional curses functions absent on old SVr4 curses (GH-154057)

Build hygiene so the curses modules build against a limited curses (e.g. the
native SVr4 curses of illumos/Solaris), matching how other optional functions
are already gated:

* Probe and #ifdef-gate the X/Open attr_t functions (window.attr_get/attr_set/
  attr_on/attr_off/color_set), the soft-label attribute functions
  (slk_attr_on/off/set, slk_color) and scr_set(); scr_set is probed separately
  from the scr_dump family, which SVr4 has without it.
* Stop gating update_lines_cols() on resizeterm(): it only reads LINES/COLS and
  is used unconditionally (e.g. by set_term()), so a build without resizeterm()
  failed to link.
* On Solaris/illumos define _BOOL (and include <stdbool.h>) so the SVr4
  <curses.h> "typedef char bool" does not clash with C's bool.

test.test_curses: skip or guard the tests that use the now-optional functions,
split test_attributes so its chtype-based part still runs, and treat the native
curses of NetBSD and illumos/Solaris as having broken newterm() (they crash on
repeated newterm()/delscreen(), like ncurses before 6.5).

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

Author: serhiy-storchaka

Include/py_curses.h

@@ -43,6 +43,15 @@
 #  define PDC_NCMOUSE
 #endif
 
+/* On Solaris/illumos, the SVr4 <curses.h> does "typedef char bool;", which
+   clashes with C's bool from <stdbool.h>.  Define _BOOL to suppress it, and
+   include <stdbool.h> for the bool the header then needs.  ncurses ignores
+   _BOOL. */
+#if defined(__sun) && !defined(_BOOL)
+#  include <stdbool.h>
+#  define _BOOL
+#endif
+
 #if defined(HAVE_NCURSESW_NCURSES_H)
 #  include <ncursesw/ncurses.h>
 #elif defined(HAVE_NCURSESW_CURSES_H)

Lib/test/test_curses.py

@@ -84,10 +84,15 @@ def wrapped(self, *args, **kwargs):
 term = os.environ.get('TERM')
 SHORT_MAX = 0x7fff
 
-# ncurses before 6.5 can crash on repeated newterm().  Fall back to initscr()
-# and skip the tests that need several screens.
+# ncurses before 6.5, and the native curses of NetBSD and illumos/Solaris,
+# crash on repeated newterm()/delscreen(); fall back to initscr() and skip the
+# multi-screen tests.  The native ones are keyed off the platform so a fixed
+# version can be excluded later.
 _ncurses_version = getattr(curses, 'ncurses_version', None)
-BROKEN_NEWTERM = _ncurses_version is not None and _ncurses_version < (6, 5)
+if _ncurses_version is not None:
+    BROKEN_NEWTERM = _ncurses_version < (6, 5)
+else:
+    BROKEN_NEWTERM = sys.platform.startswith(('netbsd', 'sunos'))
 USE_NEWTERM = hasattr(curses, 'newterm') and not BROKEN_NEWTERM
 
 # Older macOS reports a variation selector as a spacing character (wcwidth()
@@ -1140,8 +1145,17 @@ def test_attributes(self):
         win.standout()
         win.standend()
 
+        # attron()/attroff()/attrset() reject a bad attribute.
+        self.assertRaises(OverflowError, win.attron, 1 << 64)
+        self.assertRaises(OverflowError, win.attroff, -1)
+        self.assertRaises(OverflowError, win.attrset, 1 << 64)
+        self.assertRaises(TypeError, win.attron, 'x')
+
+    @requires_curses_window_meth('attr_set')
+    def test_attr(self):
         # The attr_*() family works on attr_t attributes paired with a color
         # pair, unlike the chtype-based attron()/attroff()/attrset().
+        win = curses.newwin(5, 15, 5, 2)
         win.attr_set(curses.A_BOLD | curses.A_UNDERLINE)
         attrs, pair = win.attr_get()
         self.assertTrue(attrs & curses.A_BOLD)
@@ -1167,13 +1181,9 @@ def test_attributes(self):
         self.assertRaises(OverflowError, win.attr_set, -1)
         self.assertRaises(OverflowError, win.attr_on, -1)
         self.assertRaises(OverflowError, win.attr_set, 1 << 64)
-        # attron()/attroff()/attrset() reject a bad attribute too.
-        self.assertRaises(OverflowError, win.attron, 1 << 64)
-        self.assertRaises(OverflowError, win.attroff, -1)
-        self.assertRaises(OverflowError, win.attrset, 1 << 64)
-        self.assertRaises(TypeError, win.attron, 'x')
 
     @requires_colors
+    @requires_curses_window_meth('attr_set')
     def test_attr_color_pair(self):
         win = curses.newwin(5, 15, 5, 2)
         curses.init_pair(1, curses.COLOR_RED, curses.COLOR_BLACK)
@@ -1383,8 +1393,10 @@ def test_scr_dump(self):
             stdscr.refresh()
             self.assertIsNone(curses.scr_restore(dump))
             # scr_init() and scr_set() also accept a dump file and return None.
+            # scr_set() is not available on every curses (e.g. old SVr4).
             self.assertIsNone(curses.scr_init(dump))
-            self.assertIsNone(curses.scr_set(dump))
+            if hasattr(curses, 'scr_set'):
+                self.assertIsNone(curses.scr_set(dump))
             # A bytes (path-like) filename is accepted too.
             curses.scr_dump(os.fsencode(dump))
             # Restoring from a missing file is an error.
@@ -1846,9 +1858,11 @@ def test_escdelay(self):
     def test_tabsize(self):
         tabsize = curses.get_tabsize()
         self.assertIsInstance(tabsize, int)
-        curses.set_tabsize(4)
-        self.assertEqual(curses.get_tabsize(), 4)
-        curses.set_tabsize(tabsize)
+        # set_tabsize() is not available on every curses (e.g. old SVr4).
+        if hasattr(curses, 'set_tabsize'):
+            curses.set_tabsize(4)
+            self.assertEqual(curses.get_tabsize(), 4)
+            curses.set_tabsize(tabsize)
 
     @requires_curses_func('getsyx')
     def test_getsyx(self):

Misc/NEWS.d/next/Build/2026-07-19-07-48-43.gh-issue-154055.FemUJU.rst

@@ -0,0 +1,4 @@
+The :mod:`curses` and :mod:`curses.panel` modules can now be built against a
+curses library that lacks the X/Open ``attr_t`` and soft-label attribute
+functions, ``scr_set()`` or ``resizeterm()`` -- such as the native SVr4 curses
+of illumos and Solaris.  These functions are probed and used only when present.

Modules/_cursesmodule.c

@@ -2433,6 +2433,7 @@ _curses_window_attrset_impl(PyCursesWindowObject *self, attr_t attr)
     return curses_window_check_err(self, rtn, "wattrset", "attrset");
 }
 
+#ifdef HAVE_CURSES_WATTR_GET
 /*[clinic input]
 _curses.window.attr_get
 
@@ -2458,7 +2459,9 @@ _curses_window_attr_get_impl(PyCursesWindowObject *self)
     }
     return Py_BuildValue("(ki)", (unsigned long)attrs, (int)pair);
 }
+#endif /* HAVE_CURSES_WATTR_GET */
 
+#ifdef HAVE_CURSES_WATTR_SET
 /*[clinic input]
 _curses.window.attr_set
 
@@ -2482,7 +2485,9 @@ _curses_window_attr_set_impl(PyCursesWindowObject *self, attr_t attr,
 #endif
     return curses_window_check_err(self, rtn, "wattr_set", "attr_set");
 }
+#endif /* HAVE_CURSES_WATTR_SET */
 
+#ifdef HAVE_CURSES_WATTR_ON
 /*[clinic input]
 _curses.window.attr_on
 
@@ -2499,7 +2504,9 @@ _curses_window_attr_on_impl(PyCursesWindowObject *self, attr_t attr)
     int rtn = wattr_on(self->win, attr, NULL);
     return curses_window_check_err(self, rtn, "wattr_on", "attr_on");
 }
+#endif /* HAVE_CURSES_WATTR_ON */
 
+#ifdef HAVE_CURSES_WATTR_OFF
 /*[clinic input]
 _curses.window.attr_off
 
@@ -2516,7 +2523,9 @@ _curses_window_attr_off_impl(PyCursesWindowObject *self, attr_t attr)
     int rtn = wattr_off(self->win, attr, NULL);
     return curses_window_check_err(self, rtn, "wattr_off", "attr_off");
 }
+#endif /* HAVE_CURSES_WATTR_OFF */
 
+#ifdef HAVE_CURSES_WCOLOR_SET
 /*[clinic input]
 _curses.window.color_set
 
@@ -2538,6 +2547,7 @@ _curses_window_color_set_impl(PyCursesWindowObject *self, int pair)
 #endif
     return curses_window_check_err(self, rtn, "wcolor_set", "color_set");
 }
+#endif /* HAVE_CURSES_WCOLOR_SET */
 
 /*[clinic input]
 _curses.window.getattrs
@@ -6083,6 +6093,7 @@ _curses_scr_init(PyObject *module, PyObject *filename)
 /*[clinic end generated code: output=2e861d381d710419 input=81c45e4702124ef6]*/
 ScreenDumpFunctionBody(scr_init)
 
+#ifdef HAVE_CURSES_SCR_SET
 /*[clinic input]
 _curses.scr_set
 
@@ -6099,6 +6110,7 @@ static PyObject *
 _curses_scr_set(PyObject *module, PyObject *filename)
 /*[clinic end generated code: output=6056fdec12c5935f input=d248c20543cc289b]*/
 ScreenDumpFunctionBody(scr_set)
+#endif /* HAVE_CURSES_SCR_SET */
 #endif /* HAVE_CURSES_SCR_DUMP */
 
 /*[clinic input]
@@ -7462,9 +7474,10 @@ _curses_qiflush_impl(PyObject *module, int flag)
     Py_RETURN_NONE;
 }
 
-#if defined(HAVE_CURSES_RESIZETERM) || defined(HAVE_CURSES_RESIZE_TERM)
 /* Internal helper used for updating curses.LINES, curses.COLS, _curses.LINES
- * and _curses.COLS. Returns 1 on success and 0 on failure. */
+ * and _curses.COLS. Returns 1 on success and 0 on failure.  Used
+ * unconditionally (e.g. by set_term()), so it must not be gated on resizeterm().
+ */
 static int
 update_lines_cols(PyObject *private_module)
 {
@@ -7533,8 +7546,6 @@ _curses_update_lines_cols_impl(PyObject *module)
     Py_RETURN_NONE;
 }
 
-#endif
-
 /*[clinic input]
 _curses.raw
 
@@ -8371,6 +8382,7 @@ _curses_slk_attr_impl(PyObject *module)
 }
 #endif
 
+#ifdef HAVE_CURSES_SLK_ATTR_ON
 /*[clinic input]
 _curses.slk_attr_on
 
@@ -8388,7 +8400,9 @@ _curses_slk_attr_on_impl(PyObject *module, attr_t attr)
     return curses_check_err(module, slk_attr_on(attr, NULL),
                             "slk_attr_on", NULL);
 }
+#endif /* HAVE_CURSES_SLK_ATTR_ON */
 
+#ifdef HAVE_CURSES_SLK_ATTR_OFF
 /*[clinic input]
 _curses.slk_attr_off
 
@@ -8406,7 +8420,9 @@ _curses_slk_attr_off_impl(PyObject *module, attr_t attr)
     return curses_check_err(module, slk_attr_off(attr, NULL),
                             "slk_attr_off", NULL);
 }
+#endif /* HAVE_CURSES_SLK_ATTR_OFF */
 
+#ifdef HAVE_CURSES_SLK_ATTR_SET
 /*[clinic input]
 _curses.slk_attr_set
 
@@ -8430,7 +8446,9 @@ _curses_slk_attr_set_impl(PyObject *module, attr_t attr, int pair)
 #endif
     return curses_check_err(module, rtn, "slk_attr_set", NULL);
 }
+#endif /* HAVE_CURSES_SLK_ATTR_SET */
 
+#ifdef HAVE_CURSES_SLK_COLOR
 /*[clinic input]
 _curses.slk_color
 
@@ -8447,6 +8465,7 @@ _curses_slk_color_impl(PyObject *module, int pair)
     PyCursesStatefulInitialised(module);
     return curses_check_err(module, slk_color((short)pair), "slk_color", NULL);
 }
+#endif /* HAVE_CURSES_SLK_COLOR */
 
 #ifdef HAVE_CURSES_USE_ENV
 /*[clinic input]