bundle: more comments about the different header types, remove useless if

mercurial/changegroup.py

@@ -43,7 +43,9 b' class nocompress(object):'
         return ""
 
 bundletypes = {
-    "": ("", nocompress),
+    "": ("", nocompress), # only when using unbundle on ssh and old http servers
+                          # since the unification ssh accepts a header but there
+                          # is no capability signaling it.
     "HG10UN": ("HG10UN", nocompress),
     "HG10BZ": ("HG10", lambda: bz2.BZ2Compressor()),
     "HG10GZ": ("HG10GZ", lambda: zlib.compressobj()),

mercurial/httprepo.py

@@ -147,19 +147,18 b' class httprepository(wireproto.wirerepos'
         # have to stream bundle to a temp file because we do not have
         # http 1.1 chunked transfer.
 
-        type = ""
         types = self.capable('unbundle')
-        # servers older than d1b16a746db6 will send 'unbundle' as a
-        # boolean capability
         try:
             types = types.split(',')
         except AttributeError:
+            # servers older than d1b16a746db6 will send 'unbundle' as a
+            # boolean capability. They only support headerless/uncompressed
+            # bundles.
             types = [""]
-        if types:
-            for x in types:
-                if x in changegroup.bundletypes:
-                    type = x
-                    break
+        for x in types:
+            if x in changegroup.bundletypes:
+                type = x
+                break
 
         tempname = changegroup.writebundle(cg, None, type)
         fp = url.httpsendfile(self.ui, tempname, "rb")