Add option to disable show-source for calling tools

src/flake8/main/options.py

@@ -282,6 +282,13 @@ def register_default_options(option_manager):
         parse_from_config=True,
         help="Show the source generate each error or warning.",
     )
+    add_option(
+        "--no-show-source",
+        action="store_false",
+        dest="show_source",
+        parse_from_config=False,
+        help="Negate --show-source",
+    )
 
     add_option(
         "--statistics",

tests/integration/test_main.py

@@ -108,6 +108,31 @@ t.py:2:1: F401 'sys' imported but unused
     assert err == ''
 
 
+def test_show_source_option(tmpdir, capsys):
+    """Ensure that --show-source and --no-show-source work."""
+    with tmpdir.as_cwd():
+        tmpdir.join('tox.ini').write('[flake8]\nshow_source = true\n')
+        tmpdir.join('t.py').write('import os\n')
+        _call_main(['t.py'], retv=1)
+
+    out, err = capsys.readouterr()
+    assert out == '''\
+t.py:1:1: F401 'os' imported but unused
+import os
+^
+'''
+    assert err == ''
+
+    with tmpdir.as_cwd():
+        _call_main(['t.py', '--no-show-source'], retv=1)
+
+    out, err = capsys.readouterr()
+    assert out == '''\
+t.py:1:1: F401 'os' imported but unused
+'''
+    assert err == ''
+
+
 def test_extend_exclude(tmpdir, capsys):
     """Ensure that `flake8 --extend-exclude` works."""
     for d in ['project', 'vendor', 'legacy', '.git', '.tox', '.hg']: