Merge branch 'output_file_fix' into 'master'

Fix --output-file regression

Closes #637

See merge request pycqa/flake8!426

src/flake8/api/legacy.py

@@ -29,7 +29,7 @@ def get_style_guide(**kwargs):
         :class:`StyleGuide`
     """
     application = app.Application()
-    prelim_opts, remaining_args = application.parse_preliminary_options([])
+    prelim_opts = application.parse_preliminary_options([])
     flake8.configure_logging(prelim_opts.verbose, prelim_opts.output_file)
     config_finder = config.ConfigFileFinder(
         application.program,
@@ -40,9 +40,7 @@ def get_style_guide(**kwargs):
 
     application.find_plugins(config_finder)
     application.register_plugin_options()
-    application.parse_configuration_and_cli(
-        config_finder, remaining_args,
-    )
+    application.parse_configuration_and_cli(config_finder, [])
     # We basically want application.initialize to be called but with these
     # options set instead before we make our formatter, notifier, internal
     # style guide and file checker manager.

src/flake8/main/application.py

@@ -5,7 +5,7 @@ import argparse
 import logging
 import sys
 import time
-from typing import Dict, List, Optional, Set, Tuple
+from typing import Dict, List, Optional, Set
 
 import flake8
 from flake8 import checker
@@ -95,7 +95,7 @@ class Application(object):
         self.parsed_diff = {}  # type: Dict[str, Set[int]]
 
     def parse_preliminary_options(self, argv):
-        # type: (List[str]) -> Tuple[argparse.Namespace, List[str]]
+        # type: (List[str]) -> argparse.Namespace
         """Get preliminary options from the CLI, pre-plugin-loading.
 
         We need to know the values of a few standard options so that we can
@@ -112,7 +112,7 @@ class Application(object):
         :rtype:
             (argparse.Namespace, list)
         """
-        return self.prelim_arg_parser.parse_known_args(argv)
+        return self.prelim_arg_parser.parse_known_args(argv)[0]
 
     def exit(self):
         # type: () -> None
@@ -312,7 +312,7 @@ class Application(object):
         """
         # NOTE(sigmavirus24): When updating this, make sure you also update
         # our legacy API calls to these same methods.
-        prelim_opts, remaining_args = self.parse_preliminary_options(argv)
+        prelim_opts = self.parse_preliminary_options(argv)
         flake8.configure_logging(prelim_opts.verbose, prelim_opts.output_file)
         config_finder = config.ConfigFileFinder(
             self.program,
@@ -322,9 +322,7 @@ class Application(object):
         )
         self.find_plugins(config_finder)
         self.register_plugin_options()
-        self.parse_configuration_and_cli(
-            config_finder, remaining_args,
-        )
+        self.parse_configuration_and_cli(config_finder, argv)
         self.make_formatter()
         self.make_guide()
         self.make_file_checker_manager()

tests/integration/test_main.py

@@ -246,3 +246,17 @@ def test_file_not_found(tmpdir, capsys):
     out, err = capsys.readouterr()
     assert out.startswith("i-do-not-exist:0:1: E902")
     assert err == ""
+
+
+def test_output_file(tmpdir, capsys):
+    """Ensure that --output-file is honored."""
+    tmpdir.join('t.py').write('import os\n')
+
+    with tmpdir.as_cwd():
+        _call_main(['t.py', '--output-file=f'], retv=1)
+
+    out, err = capsys.readouterr()
+    assert out == err == ""
+
+    expected = "t.py:1:1: F401 'os' imported but unused\n"
+    assert tmpdir.join('f').read() == expected

tests/unit/test_application.py

@@ -79,28 +79,22 @@ def test_returns_specified_plugin(application):
 
 def test_prelim_opts_args(application):
     """Verify we get sensible prelim opts and args."""
-    opts, args = application.parse_preliminary_options(
+    opts = application.parse_preliminary_options(
         ['--foo', '--verbose', 'src', 'setup.py', '--statistics', '--version'])
 
     assert opts.verbose
-    assert args == ['--foo', 'src', 'setup.py', '--statistics', '--version']
 
 
 def test_prelim_opts_ignore_help(application):
     """Verify -h/--help is not handled."""
-    # GIVEN
-
-    # WHEN
-    _, args = application.parse_preliminary_options(['--help', '-h'])
-
-    # THEN
-    assert args == ['--help', '-h']
+    # normally argparse would `SystemExit` on `--help`
+    application.parse_preliminary_options(['--help', '-h'])
 
 
 def test_prelim_opts_handles_empty(application):
     """Verify empty argv lists are handled correctly."""
-    irrelevant_args = ['myexe', '/path/to/foo']
+    # this would set `.verbose` but we validate that it does not
+    irrelevant_args = ['--verbose']
     with mock.patch.object(sys, 'argv', irrelevant_args):
-        opts, args = application.parse_preliminary_options([])
-
-        assert args == []
+        opts = application.parse_preliminary_options([])
+        assert not opts.verbose

tests/unit/test_legacy_api.py

@@ -19,7 +19,7 @@ def test_get_style_guide():
         verbose=0,
     )
     mockedapp = mock.Mock()
-    mockedapp.parse_preliminary_options.return_value = (prelim_opts, [])
+    mockedapp.parse_preliminary_options.return_value = prelim_opts
     mockedapp.program = 'flake8'
     with mock.patch('flake8.api.legacy.config.ConfigFileFinder') as mock_config_finder:  # noqa: E501
         config_finder = ConfigFileFinder(mockedapp.program)