Use the fact that empty sequences are false.

parser/tst/caching.py

@@ -208,7 +208,7 @@ class AAParserAltCacheBasicTests(AAParserBasicCachingTests):
         self.cache_dir = self.get_cache_dir()
 
     def tearDown(self):
-        if len(os.listdir(self.unused_cache_loc)) > 0:
+        if os.listdir(self.unused_cache_loc):
             self.fail("original cache dir '%s' not empty" % self.unused_cache_loc)
         super().tearDown()
 
@@ -515,7 +515,7 @@ class AAParserAltCacheTests(AAParserCachingTests):
         self.cache_file = os.path.join(self.cache_dir, PROFILE)
 
     def tearDown(self):
-        if self.check_orig_cache and len(os.listdir(self.orig_cache_dir)) > 0:
+        if self.check_orig_cache and os.listdir(self.orig_cache_dir):
             self.fail("original cache dir '%s' not empty" % self.orig_cache_dir)
         super().tearDown()
 

parser/tst/gen-xtrans.py

@@ -91,7 +91,7 @@ def build_rule(leading, qual, name, perm, target):
     else:
         rule += "\t%s %s %s" % (qual, name, perm)
 
-    if target != "":
+    if target:
         rule += " -> %s" % target
 
     rule += ",\n"

utils/apparmor/aa.py

@@ -352,7 +352,7 @@ def get_output(params):
     output = output.decode('utf-8').split('\n')
 
     # Remove the extra empty string caused due to \n if present
-    if output[len(output) - 1] == '':
+    if not output[-1]:
         output.pop()
 
     return (ret, output)
@@ -637,7 +637,7 @@ def change_profile_flags(prof_filename, program, flag, set_flag):
     found = False
     depth = -1
 
-    if not flag or (type(flag) is str and flag.strip() == ''):
+    if not flag or (type(flag) is str and not flag.strip()):
         raise AppArmorBug('New flag for %s is empty' % prof_filename)
 
     with open_file_read(prof_filename) as f_in:

utils/apparmor/common.py

@@ -99,7 +99,7 @@ def recursive_print(src, dpth=0, key=''):
         if empty:
             print(tabs + '[--- empty ---]')
     elif isinstance(src, list) or isinstance(src, tuple):
-        if len(src) == 0:
+        if not src:
             print(tabs + '[--- empty ---]')
         else:
             print(tabs + "[")

utils/apparmor/easyprof.py

@@ -610,7 +610,7 @@ class AppArmorEasyProfile:
         search = '###VAR###'
         prefix = find_prefix(policy, search)
         s = "%s# No template variables specified" % prefix
-        if len(template_var) > 0:
+        if template_var:
             s = "%s# Specified profile variables" % (prefix)
             template_var.sort()
             for i in template_var:
@@ -620,7 +620,7 @@ class AppArmorEasyProfile:
         search = '###READS###'
         prefix = find_prefix(policy, search)
         s = "%s# No read paths specified" % prefix
-        if len(read_path) > 0:
+        if read_path:
             s = "%s# Specified read permissions" % (prefix)
             read_path.sort()
             for i in read_path:
@@ -631,7 +631,7 @@ class AppArmorEasyProfile:
         search = '###WRITES###'
         prefix = find_prefix(policy, search)
         s = "%s# No write paths specified" % prefix
-        if len(write_path) > 0:
+        if write_path:
             s = "%s# Specified write permissions" % (prefix)
             write_path.sort()
             for i in write_path:

utils/apparmor/regex.py

@@ -138,7 +138,7 @@ def parse_profile_start_line(line, filename):
         else:
             result[section] = None
 
-    if result['flags'] and result['flags'].strip() == '':
+    if result['flags'] and not result['flags'].strip():
         raise AppArmorException(
             _('Invalid syntax in %(filename)s: Empty set of flags in line %(line)s.'
               % {'filename': filename, 'line': line}))
@@ -204,11 +204,10 @@ def re_match_include_parse(line, rule_name):
         path = matches.group('quotedpath')
         # LP: 1738880 - parser doesn't handle relative paths everywhere, and
         # neither do we (see aa.py)
-        if rule_name == 'include' and len(path) > 0 and path[0] != '/':
+        if rule_name == 'include' and path and path[0] != '/':
             raise AppArmorException(_('Syntax error: %s must use quoted path or <...>') % rule_name)
 
-    # if path is empty or the empty string
+    if not path:
-    if path is None or path == "":
         raise AppArmorException(_('Syntax error: %s rule with empty filename') % rule_name)
 
     # LP: #1738877 - parser doesn't handle files with spaces in the name

utils/apparmor/rule/__init__.py

@@ -78,7 +78,7 @@ class BaseRule:
         if rulepart == self.ALL:
             return None, True
         elif type(rulepart) is str:
-            if len(rulepart.strip()) == 0:
+            if not rulepart.strip():
                 raise AppArmorBug(
                     'Passed empty %(partname)s to %(classname)s: %(rulepart)s'
                     % {'partname': partname, 'classname': self.__class__.__name__, 'rulepart': str(rulepart)})
@@ -503,7 +503,7 @@ def check_and_split_list(lst, allowed_keywords, all_obj, classname, keyword_name
         return None, True, None
     elif type(lst) is str:
         result_list = {lst}
-    elif type(lst) in (list, tuple, set) and (len(lst) > 0 or allow_empty_list):
+    elif type(lst) in (list, tuple, set) and (lst or allow_empty_list):
         result_list = set(lst)
     else:
         raise AppArmorBug(

utils/apparmor/rule/capability.py

@@ -49,14 +49,14 @@ class CapabilityRule(BaseRule):
         else:
             if type(cap_list) is str:
                 self.capability = {cap_list}
-            elif type(cap_list) == list and len(cap_list) > 0:
+            elif type(cap_list) == list and cap_list:
                 self.capability = set(cap_list)
             else:
                 raise AppArmorBug('Passed unknown object to CapabilityRule: %s' % str(cap_list))
             # make sure none of the cap_list arguments are blank, in
             # case we decide to return one cap per output line
             for cap in self.capability:
-                if len(cap.strip()) == 0:
+                if not cap.strip():
                     raise AppArmorBug('Passed empty capability to CapabilityRule: %s' % str(cap_list))
 
     @classmethod

utils/apparmor/rule/dbus.py

@@ -132,7 +132,7 @@ class DbusRule(BaseRule):
                 # XXX move to function _split_access()?
                 access = strip_parenthesis(details.group('access'))
                 access = access.replace(',', ' ').split()  # split by ',' or whitespace
-                if access == []:  # XXX that happens for "dbus ( )," rules - correct behaviour? (also: same for signal rules?)
+                if not access:  # XXX that happens for "dbus ( )," rules - correct behaviour? (also: same for signal rules?)
                     access = DbusRule.ALL
             else:
                 access = DbusRule.ALL

utils/apparmor/rule/rlimit.py

@@ -154,7 +154,7 @@ class RlimitRule(BaseRule):
     def size_to_int(self, value):
         number, unit = split_unit(value)
 
-        if unit == '':
+        if not unit:
             pass
         elif unit == 'K' or unit == 'KB':
             number = number * 1024
@@ -170,7 +170,7 @@ class RlimitRule(BaseRule):
     def time_to_int(self, value, default_unit):
         number, unit = split_unit(value)
 
-        if unit == '':
+        if not unit:
             unit = default_unit
 
         if unit in ('us', 'microsecond', 'microseconds'):

utils/apparmor/sandbox.py

@@ -254,7 +254,7 @@ class SandboxXserver():
             os.environ['LANG'] = old_lang
 
         os.environ["DISPLAY"] = current
-        if display == "":
+        if not display:
             raise AppArmorException("Could not find available X display")
 
         # Use dedicated .Xauthority file

utils/apparmor/severity.py

@@ -35,7 +35,7 @@ class Severity:
         with open_file_read(dbname) as database:  # open(dbname, 'r')
             for lineno, line in enumerate(database, start=1):
                 line = line.strip()  # or only rstrip and lstrip?
-                if line == '' or line.startswith('#'):
+                if not line or line.startswith('#'):
                     continue
                 if line.startswith('/'):
                     try:
@@ -104,7 +104,7 @@ class Severity:
 
     def check_subtree(self, tree, mode, sev, segments):
         """Returns the max severity from the regex tree"""
-        if len(segments) == 0:
+        if not segments:
             first = ''
         else:
             first = segments[0]

utils/test/test-aa-easyprof.py

@@ -784,7 +784,7 @@ POLICYGROUPS_DIR="%s/templates"
         if name is not None:
             args.append('--name=%s' % name)
 
-        if len(extra_args) > 0:
+        if extra_args:
             args += extra_args
 
         args.append(self.binary)

utils/test/test-network.py

@@ -42,7 +42,7 @@ class NetworkKeywordsTest(AATest):
         for af_pair in af_pairs:
             af_name = af_pair.lstrip().split(" ")[0]
             # skip max af name definition
-            if len(af_name) > 0 and af_name != "max":
+            if af_name and af_name != "max":
                 af_names.append(af_name)
 
         missing_af_names = []

utils/vim/create-apparmor.vim.py

@@ -67,7 +67,7 @@ af_pairs = re.sub('AF_', '', output.strip()).lower().split(",")
 for af_pair in af_pairs:
     af_name = af_pair.lstrip().split(" ")[0]
     # skip max af name definition
-    if len(af_name) > 0 and af_name != "max":
+    if af_name and af_name != "max":
         af_names.append(af_name)
 
 # TODO: does a "debug" flag exist? Listed in apparmor.vim.in sdFlagKey,