Add check O346 to disallow backslash line continuation

Change-Id: I992737cd73a8c883dc1580e744c93b4a33a1d01e

octaviaclient/hacking/checks.py

@@ -247,6 +247,27 @@ def check_no_eventlet_imports(logical_line):
         yield logical_line.index('eventlet'), msg
 
 
+def check_line_continuation_no_backslash(logical_line, tokens):
+    """O346 - Don't use backslashes for line continuation.
+
+    :param logical_line: The logical line to check. Not actually used.
+    :param tokens: List of tokens to check.
+    :returns: None if the tokens don't contain any issues, otherwise a tuple
+    is yielded that contains the offending index in the logical line and a
+    message describe the check validation failure.
+    """
+    backslash = None
+    for token_type, text, start, end, orig_line in tokens:
+        m = re.match(r'.*(\\)\n', orig_line)
+        if m:
+            backslash = (start[0], m.start(1))
+            break
+
+    if backslash is not None:
+        msg = 'O346 Backslash line continuations not allowed'
+        yield backslash, msg
+
+
 def factory(register):
     register(assert_true_instance)
     register(assert_equal_or_not_none)
@@ -261,3 +282,4 @@ def factory(register):
     register(check_no_basestring)
     register(check_python3_no_iteritems)
     register(check_no_eventlet_imports)
+    register(check_line_continuation_no_backslash)

octaviaclient/tests/unit/test_hacking.py

@@ -142,3 +142,10 @@ class HackingTestCase(base.BaseTestCase):
 
         self.assertEqual(0, len(list(checks.no_xrange(
             "range(45)"))))
+
+    def test_line_continuation_no_backslash(self):
+        results = list(checks.check_line_continuation_no_backslash(
+            '', [(1, 'import', (2, 0), (2, 6), 'import \\\n'),
+                 (1, 'os', (3, 4), (3, 6), '    os\n')]))
+        self.assertEqual(1, len(results))
+        self.assertEqual((2, 7), results[0][0])