Don't raise CommandError in TabbedBrowser.current_url.

TabbedBrowser.current_url used to process the qtutils.QtValueError exception
and raise a cmdexc.CommandError based on it. While this was useful for some
callers, it made handling it in others weird, and it doesn't really belong
there - so now the caller handles this.

qutebrowser/browser/commands.py

@@ -92,7 +92,14 @@ class CommandDispatcher:
 
     def _current_url(self):
         """Convenience method to get the current url."""
-        return self._tabbed_browser().current_url()
+        try:
+            return self._tabbed_browser().current_url()
+        except qtutils.QtValueError as e:
+            msg = "Current URL is invalid"
+            if e.reason:
+                msg += " ({})".format(e.reason)
+            msg += "!"
+            raise cmdexc.CommandError(msg)
 
     def _current_widget(self):
         """Get the currently active widget from a command."""

qutebrowser/commands/runners.py

@@ -26,7 +26,7 @@ from PyQt5.QtWebKitWidgets import QWebPage
 
 from qutebrowser.config import config, configexc
 from qutebrowser.commands import cmdexc, cmdutils
-from qutebrowser.utils import message, log, utils, objreg
+from qutebrowser.utils import message, log, utils, objreg, qtutils
 from qutebrowser.misc import split
 
 
@@ -35,12 +35,18 @@ def replace_variables(win_id, arglist):
     args = []
     tabbed_browser = objreg.get('tabbed-browser', scope='window',
                                 window=win_id)
-    for arg in arglist:
-        if arg == '{url}':
-            # Note we have to do this in here as the user gets an error message
-            # by current_url if no URL is open yet.
+    if '{url}' in arglist:
+        try:
             url = tabbed_browser.current_url().toString(QUrl.FullyEncoded |
                                                         QUrl.RemovePassword)
+        except qtutils.QtValueError as e:
+            msg = "Current URL is invalid"
+            if e.reason:
+                msg += " ({})".format(e.reason)
+            msg += "!"
+            raise cmdexc.CommandError(msg)
+    for arg in arglist:
+        if arg == '{url}':
             args.append(url)
         else:
             args.append(arg)

qutebrowser/mainwindow/statusbar/command.py

@@ -26,7 +26,7 @@ from qutebrowser.keyinput import modeman, modeparsers
 from qutebrowser.commands import cmdexc, cmdutils
 from qutebrowser.misc import cmdhistory
 from qutebrowser.misc import miscwidgets as misc
-from qutebrowser.utils import usertypes, log, objreg
+from qutebrowser.utils import usertypes, log, objreg, qtutils
 
 
 class Command(misc.MinimalLineEditMixin, misc.CommandLineEdit):
@@ -110,8 +110,15 @@ class Command(misc.MinimalLineEditMixin, misc.CommandLineEdit):
         tabbed_browser = objreg.get('tabbed-browser', scope='window',
                                     window=self._win_id)
         if '{url}' in text:
-            url = tabbed_browser.current_url().toString(
-                QUrl.FullyEncoded | QUrl.RemovePassword)
+            try:
+                url = tabbed_browser.current_url().toString(
+                    QUrl.FullyEncoded | QUrl.RemovePassword)
+            except qtutils.QtValueError as e:
+                msg = "Current URL is invalid"
+                if e.reason:
+                    msg += " ({})".format(e.reason)
+                msg += "!"
+                raise cmdexc.CommandError(msg)
             # FIXME we currently replace the URL in any place in the arguments,
             # rather than just replacing it if it is a dedicated argument. We
             # could split the args, but then trailing spaces would be lost, so

qutebrowser/mainwindow/tabbedbrowser.py

@@ -28,7 +28,6 @@ from PyQt5.QtGui import QIcon
 from PyQt5.QtWebKitWidgets import QWebPage
 
 from qutebrowser.config import config
-from qutebrowser.commands import cmdexc
 from qutebrowser.keyinput import modeman
 from qutebrowser.mainwindow import tabwidget
 from qutebrowser.browser import signalfilter, commands, webview
@@ -187,14 +186,8 @@ class TabbedBrowser(tabwidget.TabWidget):
             url = QUrl()
         else:
             url = widget.cur_url
-        try:
-            qtutils.ensure_valid(url)
-        except qtutils.QtValueError as e:
-            msg = "Current URL is invalid"
-            if e.reason:
-                msg += " ({})".format(e.reason)
-            msg += "!"
-            raise cmdexc.CommandError(msg)
+        # It's possible for url to be invalid, but the caller will handle that.
+        qtutils.ensure_valid(url)
         return url
 
     def shutdown(self):