py3: use native strings when forming email headers in patchbomb

Per previous changesets, encoded header's values are native str. We
complete the change in patchbomb extension to have literal header values
native str as well. Then we can also change headers' keys to be str. In
_msgid(), we still need to use encoding.strfromlocal() because usage of
os.environ is not allowed by check-code.

This finally removes the "if pycompat.ispy3:" TODO.

hgext/patchbomb.py

@@ -321,10 +321,10 b' def makepatch('
         subj = b' '.join([prefix, opts.get(b'subject') or subj])
     else:
         subj = b' '.join([prefix, subj])
-    msg[b'Subject'] = mail.headencode(ui, subj, _charsets, opts.get(b'test'))
-    msg[b'X-Mercurial-Node'] = node
-    msg[b'X-Mercurial-Series-Index'] = b'%i' % idx
-    msg[b'X-Mercurial-Series-Total'] = b'%i' % total
+    msg['Subject'] = mail.headencode(ui, subj, _charsets, opts.get(b'test'))
+    msg['X-Mercurial-Node'] = pycompat.sysstr(node)
+    msg['X-Mercurial-Series-Index'] = '%i' % idx
+    msg['X-Mercurial-Series-Total'] = '%i' % total
     return msg, subj, ds
 
 
@@ -421,7 +421,7 b' def _getbundlemsgs(repo, sender, bundle,'
     )
     emailencoders.encode_base64(datapart)
     msg.attach(datapart)
-    msg[b'Subject'] = mail.headencode(ui, subj, _charsets, opts.get('test'))
+    msg['Subject'] = mail.headencode(ui, subj, _charsets, opts.get('test'))
     return [(msg, subj, None)]
 
 
@@ -454,7 +454,7 b' def _makeintro(repo, sender, revs, patch'
 
     body = _getdescription(repo, body, sender, **opts)
     msg = mail.mimeencode(ui, body, _charsets, opts.get('test'))
-    msg[b'Subject'] = mail.headencode(ui, subj, _charsets, opts.get('test'))
+    msg['Subject'] = mail.headencode(ui, subj, _charsets, opts.get('test'))
     return (msg, subj, diffstat)
 
 
@@ -522,9 +522,11 b' def _getoutgoing(repo, dest, revs):'
 
 
 def _msgid(node, timestamp):
-    hostname = encoding.strtolocal(socket.getfqdn())
-    hostname = encoding.environ.get(b'HGHOSTNAME', hostname)
-    return b'<%s.%d@%s>' % (node, timestamp, hostname)
+    try:
+        hostname = encoding.strfromlocal(encoding.environ[b'HGHOSTNAME'])
+    except KeyError:
+        hostname = socket.getfqdn()
+    return '<%s.%d@%s>' % (node, timestamp, hostname)
 
 
 emailopts = [
@@ -912,10 +914,11 b' def email(ui, repo, *revs, **opts):'
     parent = opts.get(b'in_reply_to') or None
     # angle brackets may be omitted, they're not semantically part of the msg-id
     if parent is not None:
-        if not parent.startswith(b'<'):
-            parent = b'<' + parent
-        if not parent.endswith(b'>'):
-            parent += b'>'
+        parent = encoding.strfromlocal(parent)
+        if not parent.startswith('<'):
+            parent = '<' + parent
+        if not parent.endswith('>'):
+            parent += '>'
 
     sender_addr = eutil.parseaddr(encoding.strfromlocal(sender))[1]
     sender = mail.addressencode(ui, sender, _charsets, opts.get(b'test'))
@@ -926,50 +929,30 b' def email(ui, repo, *revs, **opts):'
     )
     for i, (m, subj, ds) in enumerate(msgs):
         try:
-            m[b'Message-Id'] = genmsgid(m[b'X-Mercurial-Node'])
+            m['Message-Id'] = genmsgid(m['X-Mercurial-Node'])
             if not firstpatch:
-                firstpatch = m[b'Message-Id']
-            m[b'X-Mercurial-Series-Id'] = firstpatch
+                firstpatch = m['Message-Id']
+            m['X-Mercurial-Series-Id'] = firstpatch
         except TypeError:
-            m[b'Message-Id'] = genmsgid(b'patchbomb')
+            m['Message-Id'] = genmsgid('patchbomb')
         if parent:
-            m[b'In-Reply-To'] = parent
-            m[b'References'] = parent
-        if not parent or b'X-Mercurial-Node' not in m:
-            parent = m[b'Message-Id']
+            m['In-Reply-To'] = parent
+            m['References'] = parent
+        if not parent or 'X-Mercurial-Node' not in m:
+            parent = m['Message-Id']
 
-        m[b'User-Agent'] = b'Mercurial-patchbomb/%s' % util.version()
-        m[b'Date'] = eutil.formatdate(start_time[0], localtime=True)
+        m['User-Agent'] = 'Mercurial-patchbomb/%s' % util.version().decode()
+        m['Date'] = eutil.formatdate(start_time[0], localtime=True)
 
         start_time = (start_time[0] + 1, start_time[1])
-        m[b'From'] = sender
-        m[b'To'] = ', '.join(to)
+        m['From'] = sender
+        m['To'] = ', '.join(to)
         if cc:
-            m[b'Cc'] = ', '.join(cc)
+            m['Cc'] = ', '.join(cc)
         if bcc:
-            m[b'Bcc'] = ', '.join(bcc)
+            m['Bcc'] = ', '.join(bcc)
         if replyto:
-            m[b'Reply-To'] = ', '.join(replyto)
-        # Fix up all headers to be native strings.
-        # TODO(durin42): this should probably be cleaned up above in the future.
-        if pycompat.ispy3:
-            for hdr, val in list(m.items()):
-                change = False
-                if isinstance(hdr, bytes):
-                    del m[hdr]
-                    hdr = pycompat.strurl(hdr)
-                    change = True
-                if isinstance(val, bytes):
-                    # header value should be ASCII since it's encoded by
-                    # mail.headencode(), but -n/--test disables it and raw
-                    # value of platform encoding is stored.
-                    val = encoding.strfromlocal(val)
-                    if not change:
-                        # prevent duplicate headers
-                        del m[hdr]
-                    change = True
-                if change:
-                    m[hdr] = val
+            m['Reply-To'] = ', '.join(replyto)
         if opts.get(b'test'):
             ui.status(_(b'displaying '), subj, b' ...\n')
             ui.pager(b'email')
@@ -987,7 +970,7 b' def email(ui, repo, *revs, **opts):'
             progress.update(i, item=subj)
             if not mbox:
                 # Exim does not remove the Bcc field
-                del m[b'Bcc']
+                del m['Bcc']
             fp = stringio()
             generator = mail.Generator(fp, mangle_from_=False)
             generator.flatten(m, 0)