Don't reset indent_char when we encounter E101

src/flake8/checker.py

@@ -558,16 +558,13 @@ class FileChecker(object):
 
                 for result_single in result:
                     column_offset, text = result_single
-                    error_code = self.report(
+                    self.report(
                         error_code=None,
                         line_number=self.processor.line_number,
                         column=column_offset,
                         text=text,
                         line=(override_error_line or physical_line),
                     )
-                    self.processor.check_physical_error(
-                        error_code, physical_line
-                    )
 
     def process_tokens(self):
         """Process tokens and trigger checks.

src/flake8/processor.py

@@ -261,12 +261,6 @@ class FileProcessor(object):
                     )
         return arguments
 
-    def check_physical_error(self, error_code, line):
-        # type: (str, str) -> None
-        """Update attributes based on error code and line."""
-        if error_code == "E101":
-            self.indent_char = line[0]
-
     def generate_tokens(self):  # type: () -> Generator[_Token, None, None]
         """Tokenize the file and yield the tokens.
 

tests/integration/test_main.py

@@ -51,6 +51,25 @@ index d64ac39..7d943de 100644
     assert err == ''
 
 
+def test_e101_indent_char_does_not_reset(tmpdir, capsys):
+    """Ensure that E101 with an existing indent_char does not reset it."""
+    t_py_contents = """\
+if True:
+    print('space indented')
+
+s = '''\
+\ttab indented
+'''  # noqa: E101
+
+if True:
+    print('space indented')
+"""
+
+    with tmpdir.as_cwd():
+        tmpdir.join('t.py').write(t_py_contents)
+        _call_main(['t.py'])
+
+
 def test_statistics_option(tmpdir, capsys):
     """Ensure that `flake8 --statistics` works."""
     with tmpdir.as_cwd():

tests/unit/test_file_processor.py

@@ -146,24 +146,6 @@ def test_next_line(default_options):
         assert file_processor.line_number == i
 
 
-@pytest.mark.parametrize('error_code, line, expected_indent_char', [
-    ('E101', '\t\ta = 1', '\t'),
-    ('E101', '    a = 1', ' '),
-    ('W101', 'frobulate()', None),
-    ('F821', 'class FizBuz:', None),
-])
-def test_check_physical_error(
-        error_code, line, expected_indent_char, default_options,
-):
-    """Verify we update the indet char for the appropriate error code."""
-    file_processor = processor.FileProcessor('-', default_options, lines=[
-        'Line 1',
-    ])
-
-    file_processor.check_physical_error(error_code, line)
-    assert file_processor.indent_char == expected_indent_char
-
-
 @pytest.mark.parametrize('params, args, expected_kwargs', [
     ({'blank_before': True, 'blank_lines': True},
         None,