From f8cb35615c8c2309b717ecef4cef2d68ba8f55ce Mon Sep 17 00:00:00 2001 From: Vyron Vasileiadis Date: Thu, 20 Aug 2026 22:08:50 +0300 Subject: [PATCH] gh-155974: Restore the window attributes when a curses write fails (GH-155975) addstr(), addnstr(), insstr() and insnstr() set the window rendition to the caller's attr, write, then restore the previous rendition. Since 30dde1eeb3fa the restore sits below an early return taken when the write fails, so a failed write leaves the caller's attr on the window and drops whatever the application had set with attrset(). Restore the rendition first and report the write error afterwards. A wattrset() failure is still reported when the write itself succeeded. (cherry picked from commit 83531fd39f24f873671c38b981061afe1730613f) Co-authored-by: Vyron Vasileiadis --- Lib/test/test_curses.py | 15 ++++++ ...-08-17-22-51-22.gh-issue-155974.Qz3Vb7.rst | 4 ++ Modules/_cursesmodule.c | 52 +++++++++---------- 3 files changed, 43 insertions(+), 28 deletions(-) create mode 100644 Misc/NEWS.d/next/Library/2026-08-17-22-51-22.gh-issue-155974.Qz3Vb7.rst diff --git a/Lib/test/test_curses.py b/Lib/test/test_curses.py index 8b05d2df10b3436..c07843ff6f756ac 100644 --- a/Lib/test/test_curses.py +++ b/Lib/test/test_curses.py @@ -431,6 +431,21 @@ def test_output_string_embedded_null_chars(self): self.assertRaises(ValueError, stdscr.insstr, arg) self.assertRaises(ValueError, stdscr.insnstr, arg, 1) + def test_output_string_attr_restored(self): + # A write with an attr restores the window rendition afterwards, + # whether it succeeded or failed. + win = curses.newwin(2, 10, 0, 0) + for func, args in [(win.addstr, ('x',)), (win.addnstr, ('x', 1)), + (win.insstr, ('x',)), (win.insnstr, ('x', 1))]: + with self.subTest(func.__qualname__): + win.attrset(curses.A_UNDERLINE) + # y=100 is outside the window, so the write fails. + self.assertRaises(curses.error, func, 100, 0, *args, + curses.A_BOLD) + self.assertEqual(win.getattrs(), curses.A_UNDERLINE) + func(0, 0, *args, curses.A_BOLD) + self.assertEqual(win.getattrs(), curses.A_UNDERLINE) + def test_add_string_behavior(self): # addstr() advances the cursor past the written text; addnstr() # writes at most n characters. diff --git a/Misc/NEWS.d/next/Library/2026-08-17-22-51-22.gh-issue-155974.Qz3Vb7.rst b/Misc/NEWS.d/next/Library/2026-08-17-22-51-22.gh-issue-155974.Qz3Vb7.rst new file mode 100644 index 000000000000000..8621bc49a03ccab --- /dev/null +++ b/Misc/NEWS.d/next/Library/2026-08-17-22-51-22.gh-issue-155974.Qz3Vb7.rst @@ -0,0 +1,4 @@ +Fix a regression in Python 3.15: :meth:`~curses.window.addstr`, +:meth:`~curses.window.addnstr`, :meth:`~curses.window.insstr` and +:meth:`~curses.window.insnstr` again restore the window attributes when the +write fails, instead of leaving the temporary *attr* applied. diff --git a/Modules/_cursesmodule.c b/Modules/_cursesmodule.c index 82c8e642a51154f..d0b1d9f22deae76 100644 --- a/Modules/_cursesmodule.c +++ b/Modules/_cursesmodule.c @@ -1150,15 +1150,14 @@ _curses_window_addstr_impl(PyCursesWindowObject *self, int group_left_1, } Py_DECREF(bytesobj); } - if (rtn == ERR) { - curses_window_set_error(self, funcname, "addstr"); - return NULL; - } if (use_attr) { - rtn = wattrset(self->win, attr_old); - return curses_window_check_err(self, rtn, "wattrset", "addstr"); + int attr_rtn = wattrset(self->win, attr_old); + if (rtn != ERR) { + rtn = attr_rtn; + funcname = "wattrset"; + } } - Py_RETURN_NONE; + return curses_window_check_err(self, rtn, funcname, "addstr"); } /*[clinic input] @@ -1249,15 +1248,14 @@ _curses_window_addnstr_impl(PyCursesWindowObject *self, int group_left_1, } Py_DECREF(bytesobj); } - if (rtn == ERR) { - curses_window_set_error(self, funcname, "addnstr"); - return NULL; - } if (use_attr) { - rtn = wattrset(self->win, attr_old); - return curses_window_check_err(self, rtn, "wattrset", "addnstr"); + int attr_rtn = wattrset(self->win, attr_old); + if (rtn != ERR) { + rtn = attr_rtn; + funcname = "wattrset"; + } } - Py_RETURN_NONE; + return curses_window_check_err(self, rtn, funcname, "addnstr"); } /*[clinic input] @@ -2317,15 +2315,14 @@ _curses_window_insstr_impl(PyCursesWindowObject *self, int group_left_1, } Py_DECREF(bytesobj); } - if (rtn == ERR) { - curses_window_set_error(self, funcname, "insstr"); - return NULL; - } if (use_attr) { - rtn = wattrset(self->win, attr_old); - return curses_window_check_err(self, rtn, "wattrset", "insstr"); + int attr_rtn = wattrset(self->win, attr_old); + if (rtn != ERR) { + rtn = attr_rtn; + funcname = "wattrset"; + } } - Py_RETURN_NONE; + return curses_window_check_err(self, rtn, funcname, "insstr"); } /*[clinic input] @@ -2417,15 +2414,14 @@ _curses_window_insnstr_impl(PyCursesWindowObject *self, int group_left_1, } Py_DECREF(bytesobj); } - if (rtn == ERR) { - curses_window_set_error(self, funcname, "insnstr"); - return NULL; - } if (use_attr) { - rtn = wattrset(self->win, attr_old); - return curses_window_check_err(self, rtn, "wattrset", "insnstr"); + int attr_rtn = wattrset(self->win, attr_old); + if (rtn != ERR) { + rtn = attr_rtn; + funcname = "wattrset"; + } } - Py_RETURN_NONE; + return curses_window_check_err(self, rtn, funcname, "insnstr"); } /*[clinic input]