Allow noqa to apply to lines due to continuationnoqa_continuation

5 files changed, 122 insertions, 30 deletions

diff --git a/src/flake8/checker.py b/src/flake8/checker.py
index 5482454..572c153 100644
--- a/src/flake8/checker.py
+++ b/src/flake8/checker.py
@@ -406,20 +406,20 @@ class FileChecker(object):
             self.report("E902", 0, 0, message)
             return None
 
-    def report(self, error_code, line_number, column, text, line=None):
-        # type: (str, int, int, str, Optional[str]) -> str
+    def report(self, error_code, line_number, column, text):
+        # type: (Optional[str], int, int, str) -> str
         """Report an error by storing it in the results list."""
         if error_code is None:
             error_code, text = text.split(" ", 1)
 
-        physical_line = line
         # If we're recovering from a problem in _make_processor, we will not
         # have this attribute.
-        if not physical_line and getattr(self, "processor", None):
-            physical_line = self.processor.line_for(line_number)
+        if hasattr(self, "processor"):
+            line = self.processor.noqa_line_for(line_number)
+        else:
+            line = None
 
-        error = (error_code, line_number, column, text, physical_line)
-        self.results.append(error)
+        self.results.append((error_code, line_number, column, text, line))
         return error_code
 
     def run_check(self, plugin, **arguments):
@@ -483,7 +483,7 @@ class FileChecker(object):
             column -= column_offset
         return row, column
 
-    def run_ast_checks(self):
+    def run_ast_checks(self):  # type: () -> None
         """Run all checks expecting an abstract syntax tree."""
         try:
             ast = self.processor.build_ast()
@@ -534,7 +534,7 @@ class FileChecker(object):
 
         self.processor.next_logical_line()
 
-    def run_physical_checks(self, physical_line, override_error_line=None):
+    def run_physical_checks(self, physical_line):
         """Run all checks for a given physical line.
 
         A single physical check may return multiple errors.
@@ -562,7 +562,6 @@ class FileChecker(object):
                         line_number=self.processor.line_number,
                         column=column_offset,
                         text=text,
-                        line=(override_error_line or physical_line),
                     )
 
     def process_tokens(self):
@@ -640,9 +639,7 @@ class FileChecker(object):
             line_no = token[2][0]
             with self.processor.inside_multiline(line_number=line_no):
                 for line in self.processor.split_line(token):
-                    self.run_physical_checks(
-                        line + "\n", override_error_line=token[4]
-                    )
+                    self.run_physical_checks(line + "\n")
 
 
 def _pool_init():
diff --git a/src/flake8/processor.py b/src/flake8/processor.py
index aa7f1d8..0375ed9 100644
--- a/src/flake8/processor.py
+++ b/src/flake8/processor.py
@@ -108,6 +108,8 @@ class FileProcessor(object):
         #: Statistics dictionary
         self.statistics = {"logical lines": 0}
         self._file_tokens = None  # type: Optional[List[_Token]]
+        # map from line number to the line we'll search for `noqa` in
+        self._noqa_line_mapping = None  # type: Optional[Dict[int, str]]
 
     @property
     def file_tokens(self):  # type: () -> List[_Token]
@@ -275,16 +277,51 @@ class FileProcessor(object):
         except (tokenize.TokenError, SyntaxError) as exc:
             raise exceptions.InvalidSyntax(exception=exc)
 
-    def line_for(self, line_number):
-        # type: (int) -> Optional[str]
-        """Retrieve the physical line at the specified line number."""
-        adjusted_line_number = line_number - 1
+    def _noqa_line_range(self, min_line, max_line):
+        # type: (int, int) -> Dict[int, str]
+        line_range = range(min_line, max_line + 1)
+        joined = "".join(self.lines[min_line - 1 : max_line])
+        return dict.fromkeys(line_range, joined)
+
+    def noqa_line_for(self, line_number):  # type: (int) -> Optional[str]
+        """Retrieve the line which will be used to determine noqa."""
+        if self._noqa_line_mapping is None:
+            try:
+                file_tokens = self.file_tokens
+            except exceptions.InvalidSyntax:
+                # if we failed to parse the file tokens, we'll always fail in
+                # the future, so set this so the code does not try again
+                self._noqa_line_mapping = {}
+            else:
+                ret = {}
+
+                min_line = len(self.lines) + 2
+                max_line = -1
+                for tp, _, (s_line, _), (e_line, _), _ in file_tokens:
+                    if tp == tokenize.ENDMARKER:
+                        break
+
+                    min_line = min(min_line, s_line)
+                    max_line = max(max_line, e_line)
+
+                    if tp in (tokenize.NL, tokenize.NEWLINE):
+                        ret.update(self._noqa_line_range(min_line, max_line))
+
+                        min_line = len(self.lines) + 2
+                        max_line = -1
+
+                # in newer versions of python, a `NEWLINE` token is inserted
+                # at the end of the file even if it doesn't have one.
+                # on old pythons, they will not have hit a `NEWLINE`
+                if max_line != -1:
+                    ret.update(self._noqa_line_range(min_line, max_line))
+
+                self._noqa_line_mapping = ret
+
         # NOTE(sigmavirus24): Some plugins choose to report errors for empty
         # files on Line 1. In those cases, we shouldn't bother trying to
         # retrieve a physical line (since none exist).
-        if 0 <= adjusted_line_number < len(self.lines):
-            return self.lines[adjusted_line_number]
-        return None
+        return self._noqa_line_mapping.get(line_number)
 
     def next_line(self):  # type: () -> str
         """Get the next line from the list."""
diff --git a/tests/integration/test_checker.py b/tests/integration/test_checker.py
index 93cc239..096b350 100644
--- a/tests/integration/test_checker.py
+++ b/tests/integration/test_checker.py
@@ -15,7 +15,7 @@ EXPECTED_RESULT_PHYSICAL_LINE = (
     0,
     1,
     'Expected Message',
-    PHYSICAL_LINE,
+    None,
 )
 
 
@@ -153,11 +153,10 @@ def test_line_check_results(plugin_target, len_results):
     """Test the FileChecker class handling results from line checks."""
     file_checker = mock_file_checker_with_plugin(plugin_target)
 
-    # Results will be store in an internal array
+    # Results will be stored in an internal array
     file_checker.run_physical_checks(PHYSICAL_LINE)
-    assert file_checker.results == [
-        EXPECTED_RESULT_PHYSICAL_LINE
-    ] * len_results
+    expected = [EXPECTED_RESULT_PHYSICAL_LINE] * len_results
+    assert file_checker.results == expected
 
 
 PLACEHOLDER_CODE = 'some_line = "of" * code'
diff --git a/tests/integration/test_main.py b/tests/integration/test_main.py
index db307ba..b67992b 100644
--- a/tests/integration/test_main.py
+++ b/tests/integration/test_main.py
@@ -182,6 +182,25 @@ t.py:1:15: E711 comparison to None should be 'if cond is None:'
 '''
 
 
+def test_specific_noqa_on_line_with_continuation(tmpdir, capsys):
+    """See https://gitlab.com/pycqa/flake8/issues/375."""
+    t_py_src = '''\
+from os \\
+    import path  # noqa: F401
+
+x = """
+    trailing whitespace: \n
+"""  # noqa: W291
+'''
+
+    with tmpdir.as_cwd():
+        tmpdir.join('t.py').write(t_py_src)
+        _call_main(['t.py'], retv=0)
+
+    out, err = capsys.readouterr()
+    assert out == err == ''
+
+
 def test_obtaining_args_from_sys_argv_when_not_explicity_provided(capsys):
     """Test that arguments are obtained from 'sys.argv'."""
     with mock.patch('sys.argv', ['flake8', '--help']):
diff --git a/tests/unit/test_file_processor.py b/tests/unit/test_file_processor.py
index e5367a8..044d11b 100644
--- a/tests/unit/test_file_processor.py
+++ b/tests/unit/test_file_processor.py
@@ -122,16 +122,56 @@ def test_read_lines_ignores_empty_display_name(
     assert file_processor.filename == 'stdin'
 
 
-def test_line_for(default_options):
+def test_noqa_line_for(default_options):
     """Verify we grab the correct line from the cached lines."""
     file_processor = processor.FileProcessor('-', default_options, lines=[
-        'Line 1',
-        'Line 2',
-        'Line 3',
+        'Line 1\n',
+        'Line 2\n',
+        'Line 3\n',
     ])
 
     for i in range(1, 4):
-        assert file_processor.line_for(i) == 'Line {0}'.format(i)
+        assert file_processor.noqa_line_for(i) == 'Line {0}\n'.format(i)
+
+
+def test_noqa_line_for_continuation(default_options):
+    """Verify that the correct "line" is retrieved for continuation."""
+    src = '''\
+from foo \\
+    import bar  # 2
+
+x = """
+hello
+world
+"""  # 7
+'''
+    lines = src.splitlines(True)
+    file_processor = processor.FileProcessor('-', default_options, lines=lines)
+
+    assert file_processor.noqa_line_for(0) is None
+
+    l_1_2 = 'from foo \\\n    import bar  # 2\n'
+    assert file_processor.noqa_line_for(1) == l_1_2
+    assert file_processor.noqa_line_for(2) == l_1_2
+
+    assert file_processor.noqa_line_for(3) == '\n'
+
+    l_4_7 = 'x = """\nhello\nworld\n"""  # 7\n'
+    for i in (4, 5, 6, 7):
+        assert file_processor.noqa_line_for(i) == l_4_7
+
+    assert file_processor.noqa_line_for(8) is None
+
+
+def test_noqa_line_for_no_eol_at_end_of_file(default_options):
+    """Verify that we properly handle noqa line at the end of the file."""
+    src = 'from foo \\\nimport bar'  # no end of file newline
+    lines = src.splitlines(True)
+    file_processor = processor.FileProcessor('-', default_options, lines=lines)
+
+    l_1_2 = 'from foo \\\nimport bar'
+    assert file_processor.noqa_line_for(1) == l_1_2
+    assert file_processor.noqa_line_for(2) == l_1_2
 
 
 def test_next_line(default_options):