bpo-42681: Fix range checks for color and pair numbers in curses (GH-23874)

Author: serhiy-storchaka

Doc/library/curses.rst

@@ -112,14 +112,15 @@ The module :mod:`curses` defines the following functions:
 .. function:: color_content(color_number)
 
    Return the intensity of the red, green, and blue (RGB) components in the color
-   *color_number*, which must be between ``0`` and :const:`COLORS`.  Return a 3-tuple,
+   *color_number*, which must be between ``0`` and ``COLORS - 1``.  Return a 3-tuple,
    containing the R,G,B values for the given color, which will be between
    ``0`` (no component) and ``1000`` (maximum amount of component).
 
 
-.. function:: color_pair(color_number)
+.. function:: color_pair(pair_number)
 
-   Return the attribute value for displaying text in the specified color.  This
+   Return the attribute value for displaying text in the specified color pair.
+   Only the first 256 color pairs are supported. This
    attribute value can be combined with :const:`A_STANDOUT`, :const:`A_REVERSE`,
    and the other :const:`A_\*` attributes.  :func:`pair_number` is the counterpart
    to this function.
@@ -287,7 +288,7 @@ The module :mod:`curses` defines the following functions:
    Change the definition of a color, taking the number of the color to be changed
    followed by three RGB values (for the amounts of red, green, and blue
    components).  The value of *color_number* must be between ``0`` and
-   :const:`COLORS`.  Each of *r*, *g*, *b*, must be a value between ``0`` and
+   `COLORS - 1`.  Each of *r*, *g*, *b*, must be a value between ``0`` and
    ``1000``.  When :func:`init_color` is used, all occurrences of that color on the
    screen immediately change to the new definition.  This function is a no-op on
    most terminals; it is active only if :func:`can_change_color` returns ``True``.
@@ -300,7 +301,8 @@ The module :mod:`curses` defines the following functions:
    color number.  The value of *pair_number* must be between ``1`` and
    ``COLOR_PAIRS - 1`` (the ``0`` color pair is wired to white on black and cannot
    be changed).  The value of *fg* and *bg* arguments must be between ``0`` and
-   :const:`COLORS`.  If the color-pair was previously initialized, the screen is
+   ``COLORS - 1``, or, after calling :func:`use_default_colors`, ``-1``.
+   If the color-pair was previously initialized, the screen is
    refreshed and all occurrences of that color-pair are changed to the new
    definition.
 
@@ -450,7 +452,7 @@ The module :mod:`curses` defines the following functions:
 .. function:: pair_content(pair_number)
 
    Return a tuple ``(fg, bg)`` containing the colors for the requested color pair.
-   The value of *pair_number* must be between ``1`` and ``COLOR_PAIRS - 1``.
+   The value of *pair_number* must be between ``0`` and ``COLOR_PAIRS - 1``.
 
 
 .. function:: pair_number(attr)

Lib/test/test_curses.py

@@ -4,15 +4,15 @@
 # This script doesn't actually display anything very coherent. but it
 # does call (nearly) every method and function.
 #
-# Functions not tested: {def,reset}_{shell,prog}_mode, getch(), getstr(),
-# init_color()
+# Functions not tested: {def,reset}_{shell,prog}_mode, getch(), getstr()
 # Only called, not tested: getmouse(), ungetmouse()
 #
 
 import os
 import string
 import sys
 import tempfile
+import functools
 import unittest
 
 from test.support import requires, verbose, SaveSignals
@@ -37,6 +37,15 @@ def requires_curses_func(name):
     return unittest.skipUnless(hasattr(curses, name),
                                'requires curses.%s' % name)
 
+def requires_colors(test):
+    @functools.wraps(test)
+    def wrapped(self, *args, **kwargs):
+        if not curses.has_colors():
+            self.skipTest('requires colors support')
+        curses.start_color()
+        test(self, *args, **kwargs)
+    return wrapped
+
 term = os.environ.get('TERM')
 
 # If newterm was supported we could use it instead of initscr and not exit
@@ -48,6 +57,8 @@ class TestCurses(unittest.TestCase):
 
     @classmethod
     def setUpClass(cls):
+        if verbose:
+            print(f'TERM={term}', file=sys.stderr, flush=True)
         # testing setupterm() inside initscr/endwin
         # causes terminal breakage
         stdout_fd = sys.__stdout__.fileno()
@@ -306,31 +317,101 @@ def test_module_funcs(self):
             curses.use_env(1)
 
     # Functions only available on a few platforms
-    def test_colors_funcs(self):
-        if not curses.has_colors():
-            self.skipTest('requires colors support')
-        curses.start_color()
-        curses.init_pair(2, 1,1)
-        curses.color_content(1)
-        curses.color_pair(2)
+
+    def bad_colors(self):
+        return (-1, curses.COLORS, -2**31 - 1, 2**31, -2**63 - 1, 2**63, 2**64)
+
+    def bad_colors2(self):
+        return (curses.COLORS, 2**31, 2**63, 2**64)
+
+    def bad_pairs(self):
+        return (-1, -2**31 - 1, 2**31, -2**63 - 1, 2**63, 2**64)
+
+    @requires_colors
+    def test_color_content(self):
+        self.assertEqual(curses.color_content(curses.COLOR_BLACK), (0, 0, 0))
+        curses.color_content(0)
+        curses.color_content(curses.COLORS - 1)
+
+        for color in self.bad_colors():
+            self.assertRaises(ValueError, curses.color_content, color)
+
+    @requires_colors
+    def test_init_color(self):
+        if not curses.can_change_color:
+            self.skipTest('cannot change color')
+
+        old = curses.color_content(0)
+        try:
+            curses.init_color(0, *old)
+        except curses.error:
+            self.skipTest('cannot change color (init_color() failed)')
+        self.addCleanup(curses.init_color, 0, *old)
+        curses.init_color(0, 0, 0, 0)
+        self.assertEqual(curses.color_content(0), (0, 0, 0))
+        curses.init_color(0, 1000, 1000, 1000)
+        self.assertEqual(curses.color_content(0), (1000, 1000, 1000))
+
+        old = curses.color_content(curses.COLORS - 1)
+        curses.init_color(curses.COLORS - 1, *old)
+        self.addCleanup(curses.init_color, curses.COLORS - 1, *old)
+        curses.init_color(curses.COLORS - 1, 0, 500, 1000)
+        self.assertEqual(curses.color_content(curses.COLORS - 1), (0, 500, 1000))
+
+        for color in self.bad_colors():
+            self.assertRaises(ValueError, curses.init_color, color, 0, 0, 0)
+        for comp in (-1, 1001):
+            self.assertRaises(ValueError, curses.init_color, 0, comp, 0, 0)
+            self.assertRaises(ValueError, curses.init_color, 0, 0, comp, 0)
+            self.assertRaises(ValueError, curses.init_color, 0, 0, 0, comp)
+
+    @requires_colors
+    def test_pair_content(self):
+        if not hasattr(curses, 'use_default_colors'):
+            self.assertEqual(curses.pair_content(0),
+                             (curses.COLOR_WHITE, curses.COLOR_BLACK))
+        curses.pair_content(0)
         curses.pair_content(curses.COLOR_PAIRS - 1)
-        curses.pair_number(0)
-
-        if hasattr(curses, 'use_default_colors'):
-            curses.use_default_colors()
-
-        self.assertRaises(ValueError, curses.color_content, -1)
-        self.assertRaises(ValueError, curses.color_content, curses.COLORS + 1)
-        self.assertRaises(ValueError, curses.color_content, -2**31 - 1)
-        self.assertRaises(ValueError, curses.color_content, 2**31)
-        self.assertRaises(ValueError, curses.color_content, -2**63 - 1)
-        self.assertRaises(ValueError, curses.color_content, 2**63 - 1)
-        self.assertRaises(ValueError, curses.pair_content, -1)
-        self.assertRaises(ValueError, curses.pair_content, curses.COLOR_PAIRS)
-        self.assertRaises(ValueError, curses.pair_content, -2**31 - 1)
-        self.assertRaises(ValueError, curses.pair_content, 2**31)
-        self.assertRaises(ValueError, curses.pair_content, -2**63 - 1)
-        self.assertRaises(ValueError, curses.pair_content, 2**63 - 1)
+
+        for pair in self.bad_pairs():
+            self.assertRaises(ValueError, curses.pair_content, pair)
+
+    @requires_colors
+    def test_init_pair(self):
+        old = curses.pair_content(1)
+        curses.init_pair(1, *old)
+        self.addCleanup(curses.init_pair, 1, *old)
+
+        curses.init_pair(1, 0, 0)
+        self.assertEqual(curses.pair_content(1), (0, 0))
+        curses.init_pair(1, curses.COLORS - 1, curses.COLORS - 1)
+        self.assertEqual(curses.pair_content(1),
+                         (curses.COLORS - 1, curses.COLORS - 1))
+        curses.init_pair(curses.COLOR_PAIRS - 1, 2, 3)
+        self.assertEqual(curses.pair_content(curses.COLOR_PAIRS - 1), (2, 3))
+
+        for pair in self.bad_pairs():
+            self.assertRaises(ValueError, curses.init_pair, pair, 0, 0)
+        for color in self.bad_colors2():
+            self.assertRaises(ValueError, curses.init_pair, 1, color, 0)
+            self.assertRaises(ValueError, curses.init_pair, 1, 0, color)
+
+    @requires_colors
+    def test_color_attrs(self):
+        for pair in 0, 1, 255:
+            attr = curses.color_pair(pair)
+            self.assertEqual(curses.pair_number(attr), pair, attr)
+            self.assertEqual(curses.pair_number(attr | curses.A_BOLD), pair)
+        self.assertEqual(curses.color_pair(0), 0)
+        self.assertEqual(curses.pair_number(0), 0)
+
+    @requires_curses_func('use_default_colors')
+    @requires_colors
+    def test_use_default_colors(self):
+        self.assertIn(curses.pair_content(0),
+                      ((curses.COLOR_WHITE, curses.COLOR_BLACK), (-1, -1)))
+        curses.use_default_colors()
+        self.assertEqual(curses.pair_content(0), (-1, -1))
 
     @requires_curses_func('keyname')
     def test_keyname(self):

Misc/NEWS.d/next/Library/2020-12-20-22-50-15.bpo-42681.lDO6jb.rst

@@ -0,0 +1 @@
+Fixed range checks for color and pair numbers in :mod:`curses`.