[3.9] bpo-29566: binhex.binhex now consitently writes MacOS 9 line endings. (GH-23059) (GH-23071)

[[bpo-29566]()]() notes that binhex.binhex uses inconsistent line endings (both Unix and MacOS9 line endings are used). This PR changes this to use the MacOS9 line endings everywhere.
(cherry picked from commit 2165cea548)


Co-authored-by: Ronald Oussoren <ronaldoussoren@mac.com>

Automerge-Triggered-By: GH:ronaldoussoren

Lib/binhex.py

@@ -117,12 +117,12 @@ class _Hqxcoderengine:
         first = 0
         while first <= len(self.hqxdata) - self.linelen:
             last = first + self.linelen
-            self.ofp.write(self.hqxdata[first:last] + b'\n')
+            self.ofp.write(self.hqxdata[first:last] + b'\r')
             self.linelen = LINELEN
             first = last
         self.hqxdata = self.hqxdata[first:]
         if force:
-            self.ofp.write(self.hqxdata + b':\n')
+            self.ofp.write(self.hqxdata + b':\r')
 
     def close(self):
         if self.data:

Lib/test/test_binhex.py

@@ -48,6 +48,18 @@ class BinHexTestCase(unittest.TestCase):
 
         self.assertRaises(binhex.Error, binhex.binhex, self.fname3, self.fname2)
 
+    def test_binhex_line_endings(self):
+        # bpo-29566: Ensure the line endings are those for macOS 9
+        with open(self.fname1, 'wb') as f:
+            f.write(self.DATA)
+
+        binhex.binhex(self.fname1, self.fname2)
+
+        with open(self.fname2, 'rb') as fp:
+            contents = fp.read()
+
+        self.assertNotIn(b'\n', contents)
+
 def test_main():
     support.run_unittest(BinHexTestCase)
 

Misc/NEWS.d/next/Library/2020-10-31-13-28-36.bpo-29566.6aDbty.rst

@@ -0,0 +1 @@
+``binhex.binhex()`` consisently writes macOS 9 line endings.