Add :config-clear and :config-unset

See #2794

doc/changelog.asciidoc

@@ -60,7 +60,10 @@ Added
   Together with the previous setting, this should make wrapper scripts
   unnecessary.
 - Proxy authentication is now supported with the QtWebEngine backend.
-- New `:config-cycle` command to cycle an option between multiple values.
+- New config commands:
+  - `:config-cycle` to cycle an option between multiple values.
+  - `:config-unset` to remove a configured option
+  - `:config-clear` to remove all configured options
 
 Changed
 ~~~~~~~

doc/help/commands.asciidoc

@@ -31,7 +31,9 @@ It is possible to run or bind multiple commands by separating them with `;;`.
 |<<bookmark-load,bookmark-load>>|Load a bookmark.
 |<<buffer,buffer>>|Select tab by index or url/title best match.
 |<<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-unset,config-unset>>|Unset an option.
 |<<download,download>>|Download a given URL, or current page if no URL given.
 |<<download-cancel,download-cancel>>|Cancel the last/[count]th download.
 |<<download-clear,download-clear>>|Remove all finished downloads from the list.
@@ -202,6 +204,16 @@ The tab index to focus, starting with 1.
 === close
 Close the current window.
 
+[[config-clear]]
+=== config-clear
+Syntax: +:config-clear [*--save*]+
+
+Set all settings back to their default.
+
+==== optional arguments
+* +*-s*+, +*--save*+: If given, all configuration in autoconfig.yml is also removed.
+
+
 [[config-cycle]]
 === config-cycle
 Syntax: +:config-cycle [*--temp*] [*--print*] 'option' 'values' ['values' ...]+
@@ -216,6 +228,20 @@ Cycle an option between multiple values.
 * +*-t*+, +*--temp*+: Set value temporarily until qutebrowser is closed.
 * +*-p*+, +*--print*+: Print the value after setting.
 
+[[config-unset]]
+=== config-unset
+Syntax: +:config-unset [*--temp*] 'option'+
+
+Unset an option.
+
+This sets an option back to its default and removes it from autoconfig.yml.
+
+==== positional arguments
+* +'option'+: The name of the option.
+
+==== optional arguments
+* +*-t*+, +*--temp*+: Don't touch autoconfig.yml.
+
 [[download]]
 === download
 Syntax: +:download [*--mhtml*] [*--dest* 'dest'] ['url'] ['dest-old']+

qutebrowser/config/config.py

@@ -319,6 +319,32 @@ class Config(QObject):
         if save_yaml:
             self._yaml[name] = converted
 
+    def unset(self, name, *, save_yaml=False):
+        """Set the given setting back to its default."""
+        self.get_opt(name)
+        try:
+            del self._values[name]
+        except KeyError:
+            return
+        self.changed.emit(name)
+
+        if save_yaml:
+            self._yaml.unset(name)
+
+    def clear(self, *, save_yaml=False):
+        """Clear all settings in the config.
+
+        If save_yaml=True is given, also remove all customization from the YAML
+        file.
+        """
+        old_values = self._values
+        self._values = {}
+        for name in old_values:
+            self.changed.emit(name)
+
+        if save_yaml:
+            self._yaml.clear()
+
     def update_mutables(self, *, save_yaml=False):
         """Update mutable settings if they changed.
 

qutebrowser/config/configcommands.py

@@ -178,3 +178,28 @@ class ConfigCommands:
 
         if print_:
             self._print_value(option)
+
+    @cmdutils.register(instance='config-commands')
+    @cmdutils.argument('option', completion=configmodel.option)
+    def config_unset(self, option, temp=False):
+        """Unset an option.
+
+        This sets an option back to its default and removes it from
+        autoconfig.yml.
+
+        Args:
+            option: The name of the option.
+            temp: Don't touch autoconfig.yml.
+        """
+        with self._handle_config_error():
+            self._config.unset(option, save_yaml=not temp)
+
+    @cmdutils.register(instance='config-commands')
+    def config_clear(self, save=False):
+        """Set all settings back to their default.
+
+        Args:
+            save: If given, all configuration in autoconfig.yml is also
+                  removed.
+        """
+        self._config.clear(save_yaml=save)

qutebrowser/config/configfiles.py

@@ -102,9 +102,8 @@ class YamlConfig(QObject):
         return self._values[name]
 
     def __setitem__(self, name, value):
-        self.changed.emit()
-        self._dirty = True
         self._values[name] = value
+        self._mark_changed()
 
     def __contains__(self, name):
         return name in self._values
@@ -112,6 +111,11 @@ class YamlConfig(QObject):
     def __iter__(self):
         return iter(self._values.items())
 
+    def _mark_changed(self):
+        """Mark the YAML config as changed."""
+        self._dirty = True
+        self.changed.emit()
+
     def _save(self):
         """Save the settings to the YAML file if they've changed."""
         if not self._dirty:
@@ -167,6 +171,19 @@ class YamlConfig(QObject):
         self._values = global_obj
         self._dirty = False
 
+    def unset(self, name):
+        """Remove the given option name if it's configured."""
+        try:
+            del self._values[name]
+        except KeyError:
+            return
+        self._mark_changed()
+
+    def clear(self):
+        """Clear all values from the YAML file."""
+        self._values = []
+        self._mark_changed()
+
 
 class ConfigAPI:
 

tests/helpers/stubs.py

@@ -432,6 +432,12 @@ class FakeYamlConfig:
     def __getitem__(self, key):
         return self._values[key]
 
+    def unset(self, name):
+        self._values.pop(name, None)
+
+    def clear(self):
+        self._values = []
+
 
 class StatusBarCommandStub(QLineEdit):
 

tests/unit/config/test_config.py

@@ -279,6 +279,56 @@ class TestConfig:
         conf._set_value(opt, 'never')
         assert conf._values['tabs.show'] == 'never'
 
+    @pytest.mark.parametrize('save_yaml', [True, False])
+    def test_unset(self, conf, qtbot, save_yaml):
+        name = 'tabs.show'
+        conf.set_obj(name, 'never', save_yaml=True)
+        assert conf.get(name) == 'never'
+
+        with qtbot.wait_signal(conf.changed):
+            conf.unset(name, save_yaml=save_yaml)
+
+        assert conf.get(name) == 'always'
+        if save_yaml:
+            assert name not in conf._yaml
+        else:
+            assert conf._yaml[name] == 'never'
+
+    def test_unset_never_set(self, conf, qtbot):
+        name = 'tabs.show'
+        assert conf.get(name) == 'always'
+
+        with qtbot.assert_not_emitted(conf.changed):
+            conf.unset(name)
+
+        assert conf.get(name) == 'always'
+
+    def test_unset_unknown(self, conf):
+        with pytest.raises(configexc.NoOptionError):
+            conf.unset('tabs')
+
+    @pytest.mark.parametrize('save_yaml', [True, False])
+    def test_clear(self, conf, qtbot, save_yaml):
+        name1 = 'tabs.show'
+        name2 = 'content.plugins'
+        conf.set_obj(name1, 'never', save_yaml=True)
+        conf.set_obj(name2, True, save_yaml=True)
+        assert conf._values[name1] == 'never'
+        assert conf._values[name2] is True
+
+        with qtbot.waitSignals([conf.changed, conf.changed]) as blocker:
+            conf.clear(save_yaml=save_yaml)
+
+        options = [e.args[0] for e in blocker.all_signals_and_args]
+        assert options == [name1, name2]
+
+        if save_yaml:
+            assert name1 not in conf._yaml
+            assert name2 not in conf._yaml
+        else:
+            assert conf._yaml[name1] == 'never'
+            assert conf._yaml[name2] is True
+
     def test_read_yaml(self, conf):
         assert not conf._yaml.loaded
         conf._yaml['content.plugins'] = True

tests/unit/config/test_configcommands.py

@@ -228,6 +228,41 @@ class TestCycle:
         assert msg.text == 'auto_save.session = true'
 
 
+class TestUnsetAndClear:
+
+    """Test :config-unset and :config-clear."""
+
+    @pytest.mark.parametrize('temp', [True, False])
+    def test_unset(self, commands, config_stub, temp):
+        name = 'tabs.show'
+        config_stub.set_obj(name, 'never', save_yaml=True)
+
+        commands.config_unset(name, temp=temp)
+
+        assert config_stub.get(name) == 'always'
+        if temp:
+            assert config_stub._yaml[name] == 'never'
+        else:
+            assert name not in config_stub._yaml
+
+    def test_unset_unknown_option(self, commands):
+        with pytest.raises(cmdexc.CommandError, match="No option 'tabs'"):
+            commands.config_unset('tabs')
+
+    @pytest.mark.parametrize('save', [True, False])
+    def test_clear(self, commands, config_stub, save):
+        name = 'tabs.show'
+        config_stub.set_obj(name, 'never', save_yaml=True)
+
+        commands.config_clear(save=save)
+
+        assert config_stub.get(name) == 'always'
+        if save:
+            assert name not in config_stub._yaml
+        else:
+            assert config_stub._yaml[name] == 'never'
+
+
 class TestBind:
 
     """Tests for :bind and :unbind."""

tests/unit/config/test_configfiles.py

@@ -209,6 +209,31 @@ class TestYaml:
         assert isinstance(error.exception, OSError)
         assert error.traceback is None
 
+    def test_unset(self, qtbot, config_tmpdir):
+        name = 'tabs.show'
+        yaml = configfiles.YamlConfig()
+        yaml[name] = 'never'
+
+        with qtbot.wait_signal(yaml.changed):
+            yaml.unset(name)
+
+        assert name not in yaml
+
+    def test_unset_never_set(self, qtbot, config_tmpdir):
+        yaml = configfiles.YamlConfig()
+        with qtbot.assert_not_emitted(yaml.changed):
+            yaml.unset('tabs.show')
+
+    def test_clear(self, qtbot, config_tmpdir):
+        name = 'tabs.show'
+        yaml = configfiles.YamlConfig()
+        yaml[name] = 'never'
+
+        with qtbot.wait_signal(yaml.changed):
+            yaml.clear()
+
+        assert name not in yaml
+
 
 class ConfPy: