py3: introduce a wrapper for __builtins__.{raw_,}input() In order to make this work, we have to wrap the io streams in a TextIOWrapper so that __builtins__.input() can do unicode IO on Python 3. We can't just restore the original (unicode) sys.std* because we might be running a cmdserver, and if we blindly restore sys.* to the original values then we end up breaking the cmdserver. Sadly, TextIOWrapper tries to close the underlying stream during its __del__, so we have to make a sublcass to prevent that. If you see errors like: TypeError: a bytes-like object is required, not 'str' On an input() or print() call on Python 3, the substitution of sys.std* is probably the root cause. A previous version of this change tried to put the bytesinput() method in pycompat - it turns out we need to do some encoding handling, so we have to be in a higher layer that's allowed to use mercurial.encoding.encoding. As a result, this is in util for now, with the TextIOWrapper subclass hiding in encoding.py. I'm not sure of a better place for the time being. Differential Revision: https://phab.mercurial-scm.org/D299

--- a/mercurial/ui.py	Wed Jul 26 23:33:26 2017 -0400
+++ b/mercurial/ui.py	Mon Jul 24 14:38:40 2017 -0400
@@ -1217,18 +1217,10 @@
         self.write(prompt, prompt=True)
         self.flush()
 
-        # instead of trying to emulate raw_input, swap (self.fin,
-        # self.fout) with (sys.stdin, sys.stdout)
-        oldin = sys.stdin
-        oldout = sys.stdout
-        sys.stdin = self.fin
-        sys.stdout = self.fout
         # prompt ' ' must exist; otherwise readline may delete entire line
         # - http://bugs.python.org/issue12833
         with self.timeblockedsection('stdio'):
-            line = raw_input(' ')
-        sys.stdin = oldin
-        sys.stdout = oldout
+            line = util.bytesinput(self.fin, self.fout, r' ')
 
         # When stdin is in binary mode on Windows, it can cause
         # raw_input() to emit an extra trailing carriage return