bpo-28660: Make TextWrapper break long words on hyphens (GH-22721)

1 files changed, 10 insertions, 2 deletions

diff --git a/Lib/textwrap.py b/Lib/textwrap.py
index 30e693c..841de9b 100644
--- a/Lib/textwrap.py
+++ b/Lib/textwrap.py
@@ -215,8 +215,16 @@ class TextWrapper:
         # If we're allowed to break long words, then do so: put as much
         # of the next chunk onto the current line as will fit.
         if self.break_long_words:
-            cur_line.append(reversed_chunks[-1][:space_left])
-            reversed_chunks[-1] = reversed_chunks[-1][space_left:]
+            end = space_left
+            chunk = reversed_chunks[-1]
+            if self.break_on_hyphens and len(chunk) > space_left:
+                # break after last hyphen, but only if there are
+                # non-hyphens before it
+                hyphen = chunk.rfind('-', 0, space_left)
+                if hyphen > 0 and any(c != '-' for c in chunk[:hyphen]):
+                    end = hyphen + 1
+            cur_line.append(chunk[:end])
+            reversed_chunks[-1] = chunk[end:]
 
         # Otherwise, we have to preserve the long word intact.  Only add
         # it to the current line if there's nothing already there --