Improve error reporting: do not fail on one segment in theme.py

powerline/segment.py

@@ -220,6 +220,30 @@ def process_segment(pl, side, segment_info, parsed_segments, segment, mode, colo
 
 always_true = lambda pl, segment_info, mode: True
 
+get_fallback_segment = {
+	'name': 'fallback',
+	'type': 'string',
+	'highlight_group': 'background',
+	'divider_highlight_group': None,
+	'before': None,
+	'after': None,
+	'contents': '',
+	'priority': None,
+	'draw_soft_divider': True,
+	'draw_hard_divider': True,
+	'draw_inner_divider': True,
+	'display_condition': always_true,
+	'width': None,
+	'align': None,
+	'expand': None,
+	'truncate': None,
+	'startup': None,
+	'shutdown': None,
+	'_rendered_raw': '',
+	'_rendered_hl': '',
+	'_len': None,
+	'_contents_len': None,
+}.copy
 
 def gen_segment_getter(pl, ext, common_config, theme_configs, default_module, get_module_attr, top_theme):
 	data = {

powerline/theme.py

@@ -3,8 +3,8 @@ from __future__ import (unicode_literals, division, absolute_import, print_funct
 
 import itertools
 
-from powerline.segment import gen_segment_getter, process_segment
-from powerline.lib.unicode import u
+from powerline.segment import gen_segment_getter, process_segment, get_fallback_segment
+from powerline.lib.unicode import u, safe_unicode
 
 
 def requires_segment_info(func):
@@ -147,23 +147,35 @@ class Theme(object):
 					)
 			for segment in parsed_segments:
 				self.pl.prefix = segment['name']
-				width = segment['width']
-				align = segment['align']
-				if width == 'auto' and segment['expand'] is None:
-					segment['expand'] = expand_functions.get(align)
-					if segment['expand'] is None:
-						self.pl.error('Align argument must be “r”, “l” or “c”, not “{0}”', align)
+				try:
+					width = segment['width']
+					align = segment['align']
+					if width == 'auto' and segment['expand'] is None:
+						segment['expand'] = expand_functions.get(align)
+						if segment['expand'] is None:
+							self.pl.error('Align argument must be “r”, “l” or “c”, not “{0}”', align)
 
-				segment['contents'] = segment['before'] + u(segment['contents'] if segment['contents'] is not None else '') + segment['after']
-				# Align segment contents
-				if segment['width'] and segment['width'] != 'auto':
-					if segment['align'] == 'l':
-						segment['contents'] = segment['contents'].ljust(segment['width'])
-					elif segment['align'] == 'r':
-						segment['contents'] = segment['contents'].rjust(segment['width'])
-					elif segment['align'] == 'c':
-						segment['contents'] = segment['contents'].center(segment['width'])
-				# We need to yield a copy of the segment, or else mode-dependent
-				# segment contents can’t be cached correctly e.g. when caching
-				# non-current window contents for vim statuslines
-				yield segment.copy()
+					try:
+						segment['contents'] = segment['before'] + u(
+							segment['contents'] if segment['contents'] is not None else ''
+						) + segment['after']
+					except Exception as e:
+						self.pl.exception('Failed to compute segment contents: {0}', str(e))
+						segment['contents'] = safe_unicode(segment.get('contents'))
+					# Align segment contents
+					if segment['width'] and segment['width'] != 'auto':
+						if segment['align'] == 'l':
+							segment['contents'] = segment['contents'].ljust(segment['width'])
+						elif segment['align'] == 'r':
+							segment['contents'] = segment['contents'].rjust(segment['width'])
+						elif segment['align'] == 'c':
+							segment['contents'] = segment['contents'].center(segment['width'])
+					# We need to yield a copy of the segment, or else mode-dependent
+					# segment contents can’t be cached correctly e.g. when caching
+					# non-current window contents for vim statuslines
+					yield segment.copy()
+				except Exception as e:
+					self.pl.exception('Failed to compute segment: {0}', str(e))
+					fallback = get_fallback_segment()
+					fallback.update(side=side)
+					yield fallback