Handle removed and then added files

Note: if user configuration was removed, but global configuration was not it 
will start tracking global configuration file for changes.

powerline/__init__.py

@@ -163,6 +163,8 @@ class Powerline(object):
 		self.configs_lock = Lock()
 		self.shutdown_event = Event()
 		self.configs = defaultdict(set)
+		self.missing = defaultdict(set)
+
 		self.thread = None
 
 		self.renderer_options = {}
@@ -171,6 +173,7 @@ class Powerline(object):
 
 		self.prev_common_config = None
 		self.prev_ext_config = None
+		self.pl = None
 
 		self.create_renderer(load_main=True, load_colors=True, load_colorscheme=True, load_theme=True)
 
@@ -218,6 +221,7 @@ class Powerline(object):
 					self.logger.setLevel(level)
 					self.logger.addHandler(handler)
 
+				if not self.pl:
 					self.pl = PowerlineState(self.use_daemon_threads, self.logger, self.ext)
 
 				self.renderer_options.update(
@@ -321,7 +325,12 @@ class Powerline(object):
 
 	def _load_config(self, cfg_path, type):
 		'''Load configuration and setup watcher.'''
+		try:
 			path = find_config_file(self.config_paths, cfg_path)
+		except IOError:
+			with self.configs_lock:
+				self.missing[type].add(cfg_path)
+			raise
 		with self.configs_lock:
 			self.configs[type].add(path)
 			self.watcher.watch(path)
@@ -418,6 +427,14 @@ class Powerline(object):
 					for path in paths:
 						if self.watcher(path):
 							kwargs['load_' + type] = True
+				for type, cfg_paths in self.missing.items():
+					for cfg_path in cfg_paths:
+						try:
+							find_config_file(self.config_paths, cfg_path)
+						except IOError:
+							pass
+						else:
+							kwargs['load_' + type] = True
 			if kwargs:
 				try:
 					self.create_renderer(**kwargs)

tests/test_config_reload.py

@@ -149,6 +149,8 @@ def load_json_config(config_file_path, *args, **kwargs):
 
 
 def find_config_file(search_paths, config_file):
+	if config_file.endswith('raise') and config_file not in config:
+		raise IOError('fcf:' + config_file)
 	return config_file
 
 
@@ -280,6 +282,30 @@ class TestConfigReload(TestCase):
 				self.assertEqual(p.logger._pop_msgs(), [])
 				self.assertEqual(p.renderer.local_themes, 'something')
 
+	def test_reload_unexistent(self):
+		with get_powerline(run_once=False) as p:
+			with replace_item(globals(), 'config', deepcopy(config)):
+				self.assertAccessEvents('config', 'colors', 'colorschemes/test/default', 'themes/test/default')
+				self.assertEqual(p.render(), '<1 2 1> s<2 4 False>>><3 4 4>g<4 False False>>><None None None>')
+
+				config['config']['ext']['test']['colorscheme'] = 'nonexistentraise'
+				add_watcher_events(p, 'config')
+				self.assertAccessEvents('config')
+				self.assertEqual(p.render(), '<1 2 1> s<2 4 False>>><3 4 4>g<4 False False>>><None None None>')
+				self.assertEqual(p.logger._pop_msgs(), ['test:Failed to create renderer: fcf:colorschemes/test/nonexistentraise'])
+
+				config['colorschemes/test/nonexistentraise'] = {
+					'groups': {
+						"str1": {"fg": "col1", "bg": "col3", "attr": ["bold"]},
+						"str2": {"fg": "col2", "bg": "col4", "attr": ["underline"]},
+					},
+				}
+				while not p._created_renderer():
+					sleep(0.000001)
+				self.assertAccessEvents('colorschemes/test/nonexistentraise')
+				self.assertEqual(p.render(), '<1 3 1> s<3 4 False>>><2 4 4>g<4 False False>>><None None None>')
+				self.assertEqual(p.logger._pop_msgs(), [])
+
 	def test_reload_colors(self):
 		with get_powerline(run_once=False) as p:
 			with replace_item(globals(), 'config', deepcopy(config)):
@@ -290,6 +316,7 @@ class TestConfigReload(TestCase):
 				add_watcher_events(p, 'colors')
 				self.assertAccessEvents('colors')
 				self.assertEqual(p.render(), '<5 2 1> s<2 4 False>>><3 4 4>g<4 False False>>><None None None>')
+				self.assertEqual(p.logger._pop_msgs(), [])
 
 	def test_reload_colorscheme(self):
 		with get_powerline(run_once=False) as p:
@@ -301,6 +328,7 @@ class TestConfigReload(TestCase):
 				add_watcher_events(p, 'colorschemes/test/default')
 				self.assertAccessEvents('colorschemes/test/default')
 				self.assertEqual(p.render(), '<1 3 1> s<3 4 False>>><3 4 4>g<4 False False>>><None None None>')
+				self.assertEqual(p.logger._pop_msgs(), [])
 
 	def test_reload_theme(self):
 		with get_powerline(run_once=False) as p:
@@ -312,6 +340,7 @@ class TestConfigReload(TestCase):
 				add_watcher_events(p, 'themes/test/default')
 				self.assertAccessEvents('themes/test/default')
 				self.assertEqual(p.render(), '<1 2 1> col3<2 4 False>>><3 4 4>g<4 False False>>><None None None>')
+				self.assertEqual(p.logger._pop_msgs(), [])
 
 
 replaces = {