[PATCH py3] ui: construct _keepalnum list in a python3-friendly way

[Augie Fackler]

> On Feb 19, 2017, at 9:29 AM, Yuya Nishihara <yuya at tcha.org> wrote:
> 
> On Sat, 18 Feb 2017 22:58:10 +0000, Martijn Pieters wrote:
>> On 16 Feb 2017, at 16:35, Augie Fackler <raf at durin42.com <mailto:raf at durin42.com>> wrote:
>>> +if pycompat.ispy3:
>>> +    _unicodes = [bytes([c]).decode('latin1') for c in range(256)]
>>> +    _notalnum = [s.encode('latin1') for s in _unicodes if not s.isalnum()]
>> 
>> ...
>>> +_keepalnum = ''.join(_notalnum)
>> 
>> This could be more cheaply calculated as
>> 
>>    _keepalnum = bytes(c for c in range(256) if not chr(c).isalnum())
>> 
>> This takes a third of the time.
> 
> Good catch, but I found both of them are incorrect since str.isalnum() is
> unicode aware on Python3. We'll need to use bytes.isalnum() or string.*
> constants.

Oh, gross. I missed that. I think this patch fixes it, though not with the perf wins Martijn suggested:

diff --git a/mercurial/ui.py b/mercurial/ui.py
--- a/mercurial/ui.py
+++ b/mercurial/ui.py
@@ -40,8 +40,8 @@ urlreq = util.urlreq
 
 # for use with str.translate(None, _keepalnum), to keep just alphanumerics
 if pycompat.ispy3:
-    _unicodes = [bytes([c]).decode('latin1') for c in range(256)]
-    _notalnum = [s.encode('latin1') for s in _unicodes if not s.isalnum()]
+    _bytes = [bytes([c]) for c in range(256)]
+    _notalnum = [s for s in _bytes if not s.isalnum()]
 else:
     _notalnum = [c for c in map(chr, range(256)) if not c.isalnum()]
 _keepalnum = ''.join(_notalnum)


Feel free to amend that into what’s already queued, or I can do a followup or resend as feels appropriate.