Raise CommandError instead of message.error where possible

qutebrowser/browser/commands.py

@@ -631,9 +631,8 @@ class CommandDispatcher:
         cur = self._tabs.currentWidget()
         if cur.inspector is None:
             if not config.get('general', 'developer-extras'):
-                message.error("Please enable developer-extras before using "
-                              "the webinspector!")
-                return
+                raise CommandError("Please enable developer-extras before "
+                                   "using the webinspector!")
             cur.inspector = QWebInspector()
             cur.inspector.setPage(cur.page())
             cur.inspector.show()
@@ -641,9 +640,8 @@ class CommandDispatcher:
             cur.inspector.hide()
         else:
             if not config.get('general', 'developer-extras'):
-                message.error("Please enable developer-extras before using "
-                              "the webinspector!")
-                return
+                raise CommandError("Please enable developer-extras before "
+                                   "using the webinspector!")
             else:
                 cur.inspector.show()
 
@@ -660,8 +658,7 @@ class CommandDispatcher:
         elem = frame.findFirstElement(webelem.SELECTORS[
             webelem.Group.editable_focused])
         if elem.isNull():
-            message.error("No editable element focused!")
-            return
+            raise CommandError("No editable element focused!")
         text = elem.evaluateJavaScript('this.value')
         self._editor = ExternalEditor()
         self._editor.editing_finished.connect(
@@ -678,7 +675,6 @@ class CommandDispatcher:
             text: The new text to insert.
         """
         if elem.isNull():
-            message.error("Element vanished while editing!")
-            return
+            raise CommandError("Element vanished while editing!")
         text = webelem.javascript_escape(text)
         elem.evaluateJavaScript("this.value='{}'".format(text))

qutebrowser/commands/userscripts.py

@@ -28,6 +28,7 @@ from PyQt5.QtCore import (pyqtSignal, QObject, QThread, QStandardPaths,
 import qutebrowser.utils.message as message
 from qutebrowser.utils.misc import get_standard_dir
 from qutebrowser.utils.log import procs as logger
+from qutebrowser.commands.exceptions import CommandError
 
 
 class _BlockingFIFOReader(QObject):
@@ -138,6 +139,8 @@ class _BaseUserscriptRunner(QObject):
         try:
             os.remove(self.filepath)
         except PermissionError:
+            # NOTE: Do not replace this with "raise CommandError" as it's
+            # executed async.
             message.error("Failed to delete tempfile...")
         self.filepath = None
         self.proc = None
@@ -164,6 +167,8 @@ class _BaseUserscriptRunner(QObject):
     def on_proc_error(self, error):
         """Called when the process encountered an error."""
         msg = self.PROCESS_MESSAGES[error]
+        # NOTE: Do not replace this with "raise CommandError" as it's
+        # executed async.
         message.error("Error while calling userscript: {}".format(msg))
 
 
@@ -284,7 +289,7 @@ class _DummyUserscriptRunner:
 
     def run(self, _cmd, *_args, _env=None):
         """Print an error as userscripts are not supported."""
-        message.error("Userscripts are not supported on this platform!")
+        raise CommandError("Userscripts are not supported on this platform!")
 
 
 # Here we basically just assign a generic UserscriptRunner class which does the

qutebrowser/config/config.py

@@ -303,7 +303,7 @@ class ConfigManager(QObject):
             self.set('conf', sectname, optname, value)
         except (NoOptionError, NoSectionError, ValidationError,
                 ValueError) as e:
-            message.error("set: {} - {}".format(e.__class__.__name__, e))
+            raise CommandError("set: {} - {}".format(e.__class__.__name__, e))
 
     @cmdutils.register(name='set-temp', instance='config',
                        completion=['section', 'option', 'value'])
@@ -315,7 +315,7 @@ class ConfigManager(QObject):
         try:
             self.set('temp', sectname, optname, value)
         except (NoOptionError, NoSectionError, ValidationError) as e:
-            message.error("set: {} - {}".format(e.__class__.__name__, e))
+            raise CommandError("set: {} - {}".format(e.__class__.__name__, e))
 
     def set(self, layer, sectname, optname, value):
         """Set an option.

qutebrowser/utils/editor.py

@@ -46,6 +46,8 @@ class ExternalEditor(QObject):
         try:
             os.remove(self.filename)
         except PermissionError:
+            # NOTE: Do not replace this with "raise CommandError" as it's
+            # executed async.
             message.error("Failed to delete tempfile...")
         self.text = None
         self.oshandle = None
@@ -67,6 +69,8 @@ class ExternalEditor(QObject):
             return
         try:
             if exitcode != 0:
+                # NOTE: Do not replace this with "raise CommandError" as it's
+                # executed async.
                 message.error("Editor did quit abnormally (status {})!".format(
                     exitcode))
                 return
@@ -89,6 +93,8 @@ class ExternalEditor(QObject):
                                  "from the process."),
             QProcess.UnknownError: "An unknown error occurred.",
         }
+        # NOTE: Do not replace this with "raise CommandError" as it's
+        # executed async.
         message.error("Error while calling editor: {}".format(messages[error]))
         self._cleanup()