[3.15] gh-152502: Detect the curses mouse interface portably (GH-152705) (GH-152707)

The mouse interface (getmouse(), the BUTTON* constants, ...) was gated on the
ncurses-specific NCURSES_MOUSE_VERSION macro, so it was dropped on other curses
implementations that provide it, such as NetBSD curses and PDCurses.

Gate it instead on a configure capability probe or the PDCURSES macro.  Probe
for getmouse() with its X/Open getmouse(MEVENT *) signature, since PDCurses
declares an incompatible getmouse(void) unless built for the ncurses mouse API,
which PDC_NCMOUSE now always selects.

(cherry picked from commit 7bbea4f)

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

Author: serhiy-storchaka

Include/py_curses.h

@@ -36,6 +36,13 @@
 #define NCURSES_OPAQUE 0
 #endif
 
+/* PDCurses exposes its ncurses-compatible mouse API, the one this module uses,
+   only when this is defined before the curses header is included below.
+   Ignored by other curses implementations. */
+#ifndef PDC_NCMOUSE
+#  define PDC_NCMOUSE
+#endif
+
 #if defined(HAVE_NCURSESW_NCURSES_H)
 #  include <ncursesw/ncurses.h>
 #elif defined(HAVE_NCURSESW_CURSES_H)

Misc/NEWS.d/next/Library/2026-06-30-21-40-00.gh-issue-152502.Kq3Vn7.rst

@@ -0,0 +1,5 @@
+Detect the :mod:`curses` mouse interface (:func:`~curses.getmouse`, the
+``BUTTON*`` constants, and others) with a configure capability probe or library
+macros instead of gating it on ncurses-specific macros.  It is now also
+available with other curses implementations that provide it, such as NetBSD
+curses and PDCurses (the latter underpins ``windows-curses``).

Modules/_cursesmodule.c

@@ -1681,7 +1681,7 @@ _curses_window_echochar_impl(PyCursesWindowObject *self, PyObject *ch,
     return curses_window_check_err(self, rtn, funcname, "echochar");
 }
 
-#ifdef NCURSES_MOUSE_VERSION
+#if defined(HAVE_CURSES_GETMOUSE) || defined(PDCURSES)
 /*[clinic input]
 @permit_long_summary
 _curses.window.enclose
@@ -3532,7 +3532,7 @@ _curses_getsyx_impl(PyObject *module)
 }
 #endif
 
-#ifdef NCURSES_MOUSE_VERSION
+#if defined(HAVE_CURSES_GETMOUSE) || defined(PDCURSES)
 /*[clinic input]
 _curses.getmouse
 
@@ -4253,7 +4253,7 @@ _curses_meta_impl(PyObject *module, int yes)
     return curses_check_err(module, meta(stdscr, yes), "meta", NULL);
 }
 
-#ifdef NCURSES_MOUSE_VERSION
+#if defined(HAVE_CURSES_GETMOUSE) || defined(PDCURSES)
 /*[clinic input]
 _curses.mouseinterval
 
@@ -5685,7 +5685,7 @@ cursesmodule_exec(PyObject *module)
     SetDictInt("COLOR_CYAN",        COLOR_CYAN);
     SetDictInt("COLOR_WHITE",       COLOR_WHITE);
 
-#ifdef NCURSES_MOUSE_VERSION
+#if defined(HAVE_CURSES_GETMOUSE) || defined(PDCURSES)
     /* Mouse-related constants */
     SetDictInt("BUTTON1_PRESSED",          BUTTON1_PRESSED);
     SetDictInt("BUTTON1_RELEASED",         BUTTON1_RELEASED);
@@ -5711,7 +5711,7 @@ cursesmodule_exec(PyObject *module)
     SetDictInt("BUTTON4_DOUBLE_CLICKED",   BUTTON4_DOUBLE_CLICKED);
     SetDictInt("BUTTON4_TRIPLE_CLICKED",   BUTTON4_TRIPLE_CLICKED);
 
-#if NCURSES_MOUSE_VERSION > 1
+#ifdef BUTTON5_PRESSED
     SetDictInt("BUTTON5_PRESSED",          BUTTON5_PRESSED);
     SetDictInt("BUTTON5_RELEASED",         BUTTON5_RELEASED);
     SetDictInt("BUTTON5_CLICKED",          BUTTON5_CLICKED);

Modules/clinic/_cursesmodule.c.h

@@ -7287,6 +7287,18 @@ PY_CHECK_CURSES_FUNC([set_escdelay])
 PY_CHECK_CURSES_FUNC([set_tabsize])
 PY_CHECK_CURSES_VAR([ESCDELAY])
 PY_CHECK_CURSES_VAR([TABSIZE])
+
+dnl Probe for the X/Open getmouse(MEVENT *) signature specifically: PDCurses
+dnl declares an incompatible getmouse(void) unless built for the ncurses mouse API.
+AC_CACHE_CHECK([for ncurses-style curses function getmouse],
+  [ac_cv_lib_curses_getmouse],
+  [AC_COMPILE_IFELSE(
+    [AC_LANG_PROGRAM(_CURSES_INCLUDES, [MEVENT event; (void)getmouse(&event);])],
+    [ac_cv_lib_curses_getmouse=yes],
+    [ac_cv_lib_curses_getmouse=no])])
+AS_VAR_IF([ac_cv_lib_curses_getmouse], [yes],
+  [AC_DEFINE([HAVE_CURSES_GETMOUSE], [1],
+    [Define if you have the 'getmouse' function with the X/Open signature.])])
 CPPFLAGS=$ac_save_cppflags
 ])dnl have_curses != no
 ])dnl save env

configure

@@ -191,6 +191,9 @@
 /* Define if you have the 'filter' function. */
 #undef HAVE_CURSES_FILTER
 
+/* Define if you have the 'getmouse' function with the X/Open signature. */
+#undef HAVE_CURSES_GETMOUSE
+
 /* Define to 1 if you have the <curses.h> header file. */
 #undef HAVE_CURSES_H