match: explicitly tests for None Changeset 6168d4b93634 removed the mutable default value, but did not explicitly tested for None. Such implicit testing can introduce semantic and performance issue. We move to an explicit testing for None as recommended by PEP8: https://www.python.org/dev/peps/pep-0008/#programming-recommendations

mq: explicitly tests for None Changeset fd3d8eb7f545 removed the mutable default value, but did not explicitly tested for None. Such implicit testing can introduce semantic and performance issue. We move to an explicit testing for None as recommended by PEP8: https://www.python.org/dev/peps/pep-0008/#programming-recommendations

rebase: explicitly tests for None Changeset 361bccce566a removed the mutable default value, but did not explicitly tested for None. Such implicit checking can introduce semantic and performance issue. We move to an explicit check for None as recommended by PEP8: https://www.python.org/dev/peps/pep-0008/#programming-recommendations

py3: use iter() instead of iterkeys()

localrepo: deprecated '_link' That method had a total on 1 internal user... G: changed mercurial/localrepo.py

localrepo: use self.wvfs.islink directly We are about to deprecate the helper function.

py3: convert opts back to bytes for status

parsers: handle refcounting of "parents" consistently Py_None can be refcounted like any other Python object. So do that.

py3: make py3 compat.iterbytestr simpler and faster With Python 3.4.3, timit says 11.9 usec-> 6.44 usec. With Python 3.6.0, timeit says 14.1 usec -> 9.55 usec.

py3: optimize py3 compat.bytechr using Struct.pack With Python 3.4.3, timeit says 0.437 usec -> 0.0685 usec. With Python 3.6, timeit says 0.157 usec -> 0.0907 usec. So it's faster on both versions, but the speedup varies a lot. Thanks to Gregory Szorc for the suggestion.