More email package fixes.

This repairs the linear whitespace insertion between RFC 2047 encoded words
without leaving bogus trailing spaces at the end lines that end in encoded
words.

Current status: 7F/9E

Lib/email/header.py

@@ -29,7 +29,6 @@
 
 USASCII = Charset('us-ascii')
 UTF8 = Charset('utf-8')
-TRANSITIONAL_SPACE = object()
 
 # Match encoded-word strings in the form =?charset?q?Hello_World?=
 ecre = re.compile(r'''
@@ -309,6 +308,7 @@ def encode(self, splitchars=';, \t', maxlinelen=None):
                 formatter.feed(line, charset)
                 if len(lines) > 1:
                     formatter.newline()
+            formatter.add_transition()
         return str(formatter)
 
     def _normalize(self):
@@ -341,19 +341,20 @@ def __init__(self, headerlen, maxlen, continuation_ws, splitchars):
         self._current_line = _Accumulator(headerlen)
 
     def __str__(self):
-        # Remove any trailing TRANSITIONAL_SPACE
-        if len(self._current_line) > 0:
-            last_line = self._current_line.pop()
-            if last_line is not TRANSITIONAL_SPACE:
-                self._current_line.push(last_line)
         self.newline()
         return NL.join(self._lines)
 
     def newline(self):
+        end_of_line = self._current_line.pop()
+        if end_of_line is not None:
+            self._current_line.push(end_of_line)
         if len(self._current_line) > 0:
             self._lines.append(str(self._current_line))
         self._current_line.reset()
 
+    def add_transition(self):
+        self._current_line.push(None)
+
     def feed(self, string, charset):
         # If the string itself fits on the current line in its encoded format,
         # then add it now and be done with it.
@@ -408,7 +409,6 @@ def feed(self, string, charset):
             # There was only one line.
             return
         self._current_line.push(last_line)
-        self._current_line.push(TRANSITIONAL_SPACE)
         # Everything else are full lines in themselves.
         for line in encoded_lines:
             self._lines.append(self._continuation_ws + line)
@@ -554,18 +554,20 @@ def push(self, string):
         self._current.append(string)
 
     def pop(self):
+        if not self._current:
+            return None
         return self._current.pop()
 
     def __len__(self):
-        return sum((len(string)
+        return sum(((1 if string is None else len(string))
-                    for string in self._current
+                    for string in self._current),
-                    if string is not TRANSITIONAL_SPACE),
                    self._initial_size)
 
     def __str__(self):
-        return EMPTYSTRING.join(
+        if self._current and self._current[-1] is None:
-            (' ' if string is TRANSITIONAL_SPACE else string)
+            self._current.pop()
-            for string in self._current)
+        return EMPTYSTRING.join((' ' if string is None else string)
+                                for string in self._current)
 
     def reset(self, string=None):
         self._current = []

Lib/email/test/test_email.py

@@ -1556,7 +1556,7 @@ def test_rfc2047_multiline(self):
         header = make_header(dh)
         eq(str(header),
            'Re: r\xe4ksm\xf6rg\xe5s baz foo bar r\xe4ksm\xf6rg\xe5s')
-        self.ndiffAssertEqual(header.encode(), """\
+        self.ndiffAssertEqual(header.encode(maxlinelen=76), """\
 Re: =?mac-iceland?q?r=8Aksm=9Arg=8Cs?= baz foo bar =?mac-iceland?q?r=8Aksm?=
  =?mac-iceland?q?=9Arg=8Cs?=""")