Ensure closing characters in strings are ignored (#2)

flake8_multiline_containers.py

@@ -41,29 +41,24 @@ class MultilineContainers:
     # The column where the last line that opened started
     last_starts_at = attr.ib(factory=list)
 
-    def _check_opening(
-        self,
-        open_character: str,
-        close_character: str,
-        line_number: int,
-        line: str,
-        error_code: ErrorCodes,
-    ):
-        """Implementation for JS101.
+    def _number_of_matches_in_line(
+            self,
+            open_character: str,
+            close_character: str,
+            line: str) -> tuple:
+        """Scan line and check how many times each character appears.
 
-        If open_character and close_character don't appear the same number of
-        times on the line, then open_character should be last character in the
-        line.
+        Characters inside strings are ignored.
 
         Arguments:
             open_character: Opening character for the container.
             close_character: Closing character for the container.
-            line_number: The number of the line. Reported back to flake8.
             line: The line to check.
-            error_code: The error to report if the validation fails.
+
+        Returns:
+            tuple
 
         """
-        # Scan the line for parts which are a string.
         open_matches_in_string = 0
         close_matches_in_string = 0
 
@@ -86,6 +81,34 @@ def _check_opening(
         open_times -= open_matches_in_string
         close_times -= close_matches_in_string
 
+        return open_times, close_times
+
+    def _check_opening(
+        self,
+        open_character: str,
+        close_character: str,
+        line_number: int,
+        line: str,
+        error_code: ErrorCodes,
+    ):
+        """Implementation for JS101.
+
+        If open_character and close_character don't appear the same number of
+        times on the line, then open_character should be last character in the
+        line.
+
+        Arguments:
+            open_character: Opening character for the container.
+            close_character: Closing character for the container.
+            line_number: The number of the line. Reported back to flake8.
+            line: The line to check.
+            error_code: The error to report if the validation fails.
+
+        """
+        open_times, close_times = self._number_of_matches_in_line(
+            open_character, close_character, line,
+        )
+
         if open_times >= 1 and open_times != close_times:
             self.last_starts_at.append(get_left_pad(line))
 
@@ -116,10 +139,11 @@ def _check_closing(
             error_code: The error to report if the validation fails.
 
         """
-        line_opens = True if open_character in line else False
-        line_closes = True if close_character in line else False
+        open_times, close_times = self._number_of_matches_in_line(
+            open_character, close_character, line,
+        )
 
-        if line_closes and not line_opens:
+        if close_times > 0 and open_times == 0:
             for index, i in enumerate(line):
                 if i == close_character:
                     if index != self.last_starts_at[-1]:

tests/dummy/string_examples.py

@@ -1,2 +1,8 @@
 s = '{', '}', "foo={a\n", 'bar'
 s = '{', '}', "foo=}a\n", 'bar'
+
+string_only_opens_sq = '[foobar'
+string_only_closes_sq = 'foobar]'
+
+string_only_opens_dq = "[foobar"
+string_only_closes_dq = "foobar]"