py3: config values can be bytes, but never unicode

py3: call branchmap.items() on py3 and continue to call iteritems() on py2 Mercurial's source transformer also replaces the 'def iteritems(' in branchmap by 'def items(', so we need to call whichever version is there.

py3: switch from iteritems() to items() in the topics extension The only remaining iteritems() call is on branchmap. That will be dealt with in the next patch.

py3: filter() now returns a generator, so wrap when we need a list

py3: don't depend on map() iterating over its input map(some_generator()) in py2 returns a list, while in py3 it returns a generator, so the passed-in generator won't be called unless the returned one is.

py3: implement __bool__ in addition to __nonzero__

py3: replace iter.next() by next(iter)

py3: replace xrange() by range()

py3: read sqlite3 data as bytes The py2 and py3 docs ([1] and [2]) disagree how to get bytes output, but it seems obvious that this should be "bytes" to be compatible with both. [1] https://docs.python.org/2/library/sqlite3.html#sqlite3.Connection.text_factory [2] https://docs.python.org/3/library/sqlite3.html#sqlite3.Connection.text_factory

py3: sqlite3.connect() expects str arguments