Dont import regex on calibre startup, since importing it seems to fail for unknown reasons on some linux installs

src/calibre/ebooks/css_transform_rules.py

@@ -9,15 +9,15 @@ from collections import OrderedDict
 import operator
 
 from cssutils.css import Property, CSSRule
-import regex
 
 from calibre import force_unicode
 from calibre.ebooks import parse_css_length
 from calibre.ebooks.oeb.normalize_css import normalizers, safe_parser
 
-REGEX_FLAGS = regex.VERSION1 | regex.UNICODE | regex.IGNORECASE
 
 def compile_pat(pat):
+    import regex
+    REGEX_FLAGS = regex.VERSION1 | regex.UNICODE | regex.IGNORECASE
     return regex.compile(pat, flags=REGEX_FLAGS)
 
 def all_properties(decl):
@@ -327,6 +327,7 @@ def export_rules(serialized_rules):
     return '\n'.join(lines).encode('utf-8')
 
 def import_rules(raw_data):
+    import regex
     pat = regex.compile('\s*(\S+)\s*:\s*(.+)', flags=regex.VERSION1)
     current_rule = {}
 

src/calibre/ebooks/metadata/tag_mapper.py

@@ -4,13 +4,11 @@
 
 from __future__ import (unicode_literals, division, absolute_import,
                         print_function)
-import regex
 from collections import deque
 
-REGEX_FLAGS = regex.VERSION1 | regex.WORD | regex.FULLCASE | regex.IGNORECASE | regex.UNICODE
-
-
 def compile_pat(pat):
+    import regex
+    REGEX_FLAGS = regex.VERSION1 | regex.WORD | regex.FULLCASE | regex.IGNORECASE | regex.UNICODE
     return regex.compile(pat, flags=REGEX_FLAGS)
 
 def matcher(rule):
@@ -57,7 +55,7 @@ def apply_rules(tag, rules):
                     break
                 if ac == 'replace':
                     if 'matches' in rule['match_type']:
-                        tag = regex.sub(rule['query'], rule['replace'], tag, flags=REGEX_FLAGS)
+                        tag = compile_pat(rule['query']).sub(rule['replace'], tag)
                     else:
                         tag = rule['replace']
                     if ',' in tag: