Fix various Python 3 related issues

Powerline now detects the Python version and verifies that the user has
Python 3.3 before enabling Python 3 support. To enable Python
3 support, use `python3` to execute source_plugin() in your vimrc
  instead of `python2`.

powerline/bindings/vim/__init__.py

@@ -4,9 +4,16 @@ import vim
 
 
 def source_plugin():
+	import sys
 	import os
+	if sys.version_info[:2] == (3, 3):
+		vim.command('let g:powerline_pycmd = "python3"')
+		vim.command('let g:powerline_pyeval = "py3eval"')
+	else:
+		vim.command('let g:powerline_pycmd = "python"')
+		vim.command('let g:powerline_pyeval = "pyeval"')
 	fnameescape = vim_get_func('fnameescape')
-	vim.command('source ' + fnameescape(os.path.join(os.path.abspath(os.path.dirname(__file__)), 'powerline.vim')))
+	vim.command('source ' + fnameescape(os.path.join(os.path.abspath(os.path.dirname(__file__)), 'powerline.vim')).decode('utf-8'))
 
 try:
 	_vim_globals = vim.bindeval('g:')

powerline/bindings/vim/plugin/source_plugin.vim

@@ -5,9 +5,9 @@ if ! has('python') && ! has('python3')
 	finish
 endif
 
-let s:pycmd = has('python3') ? 'python3' : 'python'
-
-exec s:pycmd ' import sys, vim'
-exec s:pycmd ' sys.path.append(vim.eval(''expand("<sfile>:h:h:h:h:h")''))'
-
-source <sfile>:h:h/powerline.vim
+python <<EOF
+import sys, vim
+sys.path.append(vim.eval('expand("<sfile>:h:h:h:h:h")'))
+from powerline.bindings.vim import source_plugin
+source_plugin()
+EOF

powerline/bindings/vim/powerline.vim

@@ -1,17 +1,13 @@
-let s:pycmd = has('python3') ? 'python3' : 'python'
+exec g:powerline_pycmd 'import uuid'
+exec g:powerline_pycmd 'from powerline.core import Powerline'
+exec g:powerline_pycmd 'powerline = Powerline("vim")'
 
-exec s:pycmd ' import uuid'
-exec s:pycmd ' from powerline.core import Powerline'
-exec s:pycmd ' powerline = Powerline("vim")'
-
-if exists('*py3eval')
-	let s:pyeval = function('py3eval')
-elseif exists('*pyeval')
-	let s:pyeval = function('pyeval')
+if exists('*'. g:powerline_pyeval)
+	let s:pyeval = function(g:powerline_pyeval)
 else
-	exec s:pycmd ' import json, vim'
+	exec g:powerline_pycmd 'import json, vim'
 	function! s:pyeval(e)
-		exec s:pycmd ' vim.command("return " + json.dumps(eval(vim.eval("a:e"))))'
+		exec g:powerline_pycmd 'vim.command("return " + json.dumps(eval(vim.eval("a:e"))))'
 	endfunction
 endif
 

powerline/theme.py

@@ -5,6 +5,12 @@ import copy
 
 from .segment import Segment
 
+try:
+	unicode()
+except NameError:
+	unicode = str
+
+
 class Theme(object):
 	def __init__(self, ext, colorscheme, theme_config, common_config):
 		self.colorscheme = colorscheme
@@ -12,7 +18,7 @@ class Theme(object):
 		self.segments = []
 		self.EMPTY_SEGMENT = {
 			'contents': None,
-			'highlight': defaultdict(lambda : {'fg': False, 'bg': False, 'attr': 0})
+			'highlight': defaultdict(lambda: {'fg': False, 'bg': False, 'attr': 0})
 			}
 		get_segment = Segment(ext, common_config['paths'], colorscheme, theme_config.get('default_module')).get
 		for side in ['left', 'right']:
@@ -42,11 +48,7 @@ class Theme(object):
 				pass
 			else:
 				continue
-			try:
-				contents = unicode(segment['contents'])
-			except NameError:
-				contents = str(segment['contents'])
-			segment['contents'] = (segment['before'] + contents + segment['after'])\
+			segment['contents'] = (segment['before'] + unicode(segment['contents']) + segment['after'])\
 				.ljust(segment['ljust'])\
 				.rjust(segment['rjust'])
 			# We need to yield a copy of the segment, or else mode-dependent