gh-160633: Break the last chunk of a broken long word in textwrap truncation

Author: qiyuhuating

Doc/library/textwrap.rst

@@ -66,6 +66,11 @@ functions should be good enough; otherwise, you should use an instance of
       >>> textwrap.shorten("Hello world", width=10, placeholder="...")
       'Hello...'
 
+   If no words can be kept before the *placeholder* (for example, when
+   *text* is a single word longer than *width*) and *break_long_words* is
+   true, the word is broken so that part of it is kept before the
+   *placeholder*.
+
    Optional keyword arguments correspond to the instance attributes of
    :class:`TextWrapper`, documented below.  Note that the whitespace is
    collapsed before the text is passed to the :class:`TextWrapper` :meth:`fill`

Lib/test/test_textwrap.py

@@ -636,9 +636,28 @@ def test_max_lines_long(self):
                         ['Did you say',
                          '"supercalifr',
                          'agilisticexp',
-                         '[...]'],
+                         'ialido [...]'],
                         max_lines=4)
 
+    def test_max_lines_long_word_broken(self):
+        # A long word broken across lines is broken further on the last
+        # line to make room for the placeholder, instead of dropping the
+        # whole remaining piece.
+        self.check_wrap('x' * 30, 10,
+                        ['xxxxxxxxxx', 'xxxx [...]'],
+                        max_lines=2)
+        self.check_wrap('x' * 30, 10,
+                        ['xxxx [...]'],
+                        max_lines=1)
+        # Not enough room for the placeholder plus any text: the
+        # placeholder-only line is kept.
+        self.check_wrap('x' * 30, 5,
+                        ['xxxxx', '[...]'],
+                        max_lines=2)
+        self.check_wrap('x' * 30, 10,
+                        ['xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx'],
+                        max_lines=2, break_long_words=False)
+
 
 class LongWordWithHyphensTestCase(BaseTestCase):
     def setUp(self):
@@ -1132,6 +1151,16 @@ def test_width_too_small_for_placeholder(self):
     def test_first_word_too_long_but_placeholder_fits(self):
         self.check_shorten("Helloo", 5, "[...]")
 
+    def test_long_word_broken_to_fit_placeholder(self):
+        # A single word longer than the width is broken further to make
+        # room for the placeholder, instead of being replaced by it alone.
+        self.check_shorten("x" * 30, 10, "xxxx [...]")
+        self.check_shorten("x" * 30, 20, "xxxxxxxxxxxxxx [...]")
+        # Not enough room for the placeholder plus any text.
+        self.check_shorten("x" * 30, 5, "[...]")
+        # Words are only broken when break_long_words is true.
+        self.check_shorten("x" * 30, 10, "[...]", break_long_words=False)
+
 
 if __name__ == '__main__':
     unittest.main()

Lib/textwrap.py

@@ -324,6 +324,23 @@ def _wrap_chunks(self, chunks):
                             cur_line.append(self.placeholder)
                             lines.append(indent + ''.join(cur_line))
                             break
+                        if (self.break_long_words and
+                            len(cur_line) == 1 and
+                            cur_line[-1].strip() and
+                            len(cur_line[-1]) == width and
+                            width - len(self.placeholder) > 0):
+                            # The placeholder does not fit after this line,
+                            # and the line consists of a single full-width
+                            # chunk: a piece of a long word broken by
+                            # _handle_long_word(), or a word exactly as wide
+                            # as the line.  Break it further instead of
+                            # dropping it whole, or the last line (and, for
+                            # shorten(), the whole text) would be replaced
+                            # by the placeholder alone.
+                            space_left = width - len(self.placeholder)
+                            cur_line[-1] = cur_line[-1][:space_left]
+                            cur_len = space_left
+                            continue
                         cur_len -= len(cur_line[-1])
                         del cur_line[-1]
                     else:

Misc/NEWS.d/next/Library/2026-10-25-13-24-45.gh-issue-160633.qiyuhuating.rst

@@ -0,0 +1,4 @@
+Fix :func:`textwrap.shorten` and :func:`textwrap.wrap` with ``max_lines``
+discarding a broken long word -- and with it, for :func:`textwrap.shorten`,
+all remaining text -- instead of breaking it further to make room for the
+placeholder.