Add a :config-edit command

See #2794

doc/help/commands.asciidoc

@@ -33,6 +33,7 @@ It is possible to run or bind multiple commands by separating them with `;;`.
 |<<close,close>>|Close the current window.
 |<<config-clear,config-clear>>|Set all settings back to their default.
 |<<config-cycle,config-cycle>>|Cycle an option between multiple values.
+|<<config-edit,config-edit>>|Open the config.py file in the editor.
 |<<config-source,config-source>>|Read a config.py file.
 |<<config-unset,config-unset>>|Unset an option.
 |<<download,download>>|Download a given URL, or current page if no URL given.
@@ -229,6 +230,15 @@ Cycle an option between multiple values.
 * +*-t*+, +*--temp*+: Set value temporarily until qutebrowser is closed.
 * +*-p*+, +*--print*+: Print the value after setting.
 
+[[config-edit]]
+=== config-edit
+Syntax: +:config-edit [*--no-source*]+
+
+Open the config.py file in the editor.
+
+==== optional arguments
+* +*-n*+, +*--no-source*+: Don't re-source the config file after editing.
+
 [[config-source]]
 === config-source
 Syntax: +:config-source [*--clear*] ['filename']+

qutebrowser/config/configcommands.py

@@ -28,6 +28,7 @@ from qutebrowser.commands import cmdexc, cmdutils
 from qutebrowser.completion.models import configmodel
 from qutebrowser.utils import objreg, utils, message, standarddir
 from qutebrowser.config import configtypes, configexc, configfiles
+from qutebrowser.misc import editor
 
 
 class ConfigCommands:
@@ -226,3 +227,27 @@ class ConfigCommands:
             configfiles.read_config_py(filename)
         except configexc.ConfigFileErrors as e:
             raise cmdexc.CommandError(e)
+
+    @cmdutils.register(instance='config-commands')
+    def config_edit(self, no_source=False):
+        """Open the config.py file in the editor.
+
+        Args:
+            no_source: Don't re-source the config file after editing.
+        """
+        def on_editing_finished():
+            """Source the new config when editing finished.
+
+            This can't use cmdexc.CommandError as it's run async.
+            """
+            try:
+                configfiles.read_config_py(filename)
+            except configexc.ConfigFileErrors as e:
+                message.error(str(e))
+
+        ed = editor.ExternalEditor(self._config)
+        if not no_source:
+            ed.editing_finished.connect(on_editing_finished)
+
+        filename = os.path.join(standarddir.config(), 'config.py')
+        ed.edit_file(filename)

tests/unit/config/test_configcommands.py

@@ -18,8 +18,10 @@
 
 """Tests for qutebrowser.config.configcommands."""
 
+import logging
+
 import pytest
-from PyQt5.QtCore import QUrl
+from PyQt5.QtCore import QUrl, QProcess
 
 from qutebrowser.config import configcommands
 from qutebrowser.commands import cmdexc
@@ -302,6 +304,53 @@ class TestSource:
         assert str(excinfo.value) == expected
 
 
+class TestEdit:
+
+    """Tests for :config-edit."""
+
+    def test_no_source(self, commands, mocker, config_tmpdir):
+        mock = mocker.patch('qutebrowser.config.configcommands.editor.'
+                            'ExternalEditor._start_editor', autospec=True)
+        commands.config_edit(no_source=True)
+        mock.assert_called_once()
+
+    @pytest.fixture
+    def patch_editor(self, mocker, config_tmpdir, data_tmpdir):
+        """Write a config.py file."""
+        def do_patch(text):
+            def _write_file(editor_self):
+                with open(editor_self._filename, 'w', encoding='utf-8') as f:
+                    f.write(text)
+                editor_self.on_proc_closed(0, QProcess.NormalExit)
+
+            return mocker.patch('qutebrowser.config.configcommands.editor.'
+                                'ExternalEditor._start_editor', autospec=True,
+                                side_effect=_write_file)
+
+        return do_patch
+
+    def test_with_sourcing(self, commands, config_stub, patch_editor):
+        assert config_stub.val.content.javascript.enabled
+        mock = patch_editor('c.content.javascript.enabled = False')
+
+        commands.config_edit()
+
+        mock.assert_called_once()
+        assert not config_stub.val.content.javascript.enabled
+
+    def test_error(self, commands, config_stub, patch_editor, message_mock,
+                   caplog):
+        patch_editor('c.foo = 42')
+
+        with caplog.at_level(logging.ERROR):
+            commands.config_edit()
+
+        msg = message_mock.getmsg()
+        expected = ("Errors occurred while reading config.py:\n"
+                    "  While setting 'foo': No option 'foo'")
+        assert msg.text == expected
+
+
 class TestBind:
 
     """Tests for :bind and :unbind."""

tests/unit/misc/test_editor.py

@@ -43,6 +43,7 @@ def editor(caplog):
     ed.editing_finished = mock.Mock()
     yield ed
     with caplog.at_level(logging.ERROR):
+        ed._remove_file = True
         ed._cleanup()