fix: port most of the way to python 3

Only most of the way because we now have to decide: if we want to keep
the current .format() interface for the config in hgrc, we have to use
unicodes to do formatting in Python 3, rather than bytes. I'm
basically fine with that, so a follow-up patch will do so.

Differential Revision: https://phab.mercurial-scm.org/D3300

hgext/fix.py

@@ -66,6 +66,7 b' from mercurial import ('
     mdiff,
     merge,
     obsolete,
+    pycompat,
     registrar,
     scmutil,
     util,
@@ -126,6 +127,7 b' def fix(ui, repo, *pats, **opts):'
     revisions are not forgotten in later ones. The --base flag can be used to
     override this default behavior, though it is not usually desirable to do so.
     """
+    opts = pycompat.byteskwargs(opts)
     if opts['all']:
         if opts['rev']:
             raise error.Abort(_('cannot specify both "--rev" and "--all"'))
@@ -513,7 +515,8 b' def getfixers(ui):'
         result[name] = Fixer()
         attrs = ui.configsuboptions('fix', name)[1]
         for key in FIXER_ATTRS:
-            setattr(result[name], '_' + key, attrs.get(key, ''))
+            setattr(result[name], pycompat.sysstr('_' + key),
+                    attrs.get(key, ''))
     return result
 
 def fixernames(ui):