python: Fix invalid escape sequences.

It appears that Python silently treats invalid escape sequences in
strings as literals, e.g. "\." is the same as "\\.".  Newer versions of
checkpatch complain, and it does seem reasonable to me to fix these.

Acked-by: Numan Siddique <nusiddiq@redhat.com>
Tested-by: Numan Siddique <nusiddiq@redhat.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>

python/build/nroff.py

@@ -274,7 +274,7 @@ def diagram_to_nroff(nodes, para):
     text_s = '.br\n'.join(["\\fL%s\n" % s for s in text if s != ""])
     return para + """
 .\\" check if in troff mode (TTY)
-.if t \{
+.if t \\{
 .PS
 boxht = .2
 textht = 1/6
@@ -283,7 +283,7 @@ fillval = .2
 .PE
 \\}
 .\\" check if in nroff mode:
-.if n \{
+.if n \\{
 .nf
 """ + text_s + """\
 .fi

python/ovs/db/schema.py

@@ -73,7 +73,7 @@ class DbSchema(object):
         parser.finish()
 
         if (version is not None and
-            not re.match('[0-9]+\.[0-9]+\.[0-9]+$', version)):
+            not re.match(r'[0-9]+\.[0-9]+\.[0-9]+$', version)):
             raise error.Error('schema version "%s" not in format x.y.z'
                               % version)
 

python/ovs/json.py

@@ -177,7 +177,7 @@ class Parser(object):
             return False
 
     __number_re = re.compile("(-)?(0|[1-9][0-9]*)"
-            "(?:\.([0-9]+))?(?:[eE]([-+]?[0-9]+))?$")
+            r"(?:\.([0-9]+))?(?:[eE]([-+]?[0-9]+))?$")
 
     def __lex_finish_number(self):
         s = self.buffer
@@ -234,7 +234,7 @@ class Parser(object):
             self.__error("leading zeros not allowed")
         elif re.match("-([^0-9]|$)", s):
             self.__error("'-' must be followed by digit")
-        elif re.match("-?(0|[1-9][0-9]*)\.([^0-9]|$)", s):
+        elif re.match(r"-?(0|[1-9][0-9]*)\.([^0-9]|$)", s):
             self.__error("decimal point must be followed by digit")
         elif re.search("e[-+]?([^0-9]|$)", s):
             self.__error("exponent must contain at least one digit")

python/ovs/unixctl/__init__.py

@@ -73,7 +73,7 @@ def command_register(name, usage, min_args, max_args, callback, aux):
 def socket_name_from_target(target):
     assert isinstance(target, strtypes)
 
-    """ On Windows an absolute path contains ':' ( i.e: C:\ ) """
+    """ On Windows an absolute path contains ':' ( i.e: C:\\ ) """
     if target.startswith('/') or target.find(':') > -1:
         return 0, target
 

python/ovs/util.py

@@ -31,7 +31,7 @@ def abs_file_name(dir_, file_name):
     This differs from os.path.abspath() in that it will never change the
     meaning of a file name.
 
-    On Windows an absolute path contains ':' ( i.e: C:\ ) """
+    On Windows an absolute path contains ':' ( i.e: C:\\ ) """
     if file_name.startswith('/') or file_name.find(':') > -1:
         return file_name
     else:

python/ovs/vlog.py

@@ -142,7 +142,7 @@ class Vlog(object):
         return re.sub(match, replace, tmp)
 
     def _format_time(self, tmp):
-        date_regex = re.compile('(%(0?[1-9]?[dD])(\{(.*)\})?)')
+        date_regex = re.compile(r'(%(0?[1-9]?[dD])(\{(.*)\})?)')
         match = date_regex.search(tmp)
 
         if match is None: