Always use JavaScript to get selection

It looks like getting the selection via the widget has issues even with Qt 5.10.

On Windows, we always get wrong results.

On Linux, it seems to be flaky. I first thought this was because of a race
between JavaScript setting the selection and Qt getting it, as now we don't use
JS to get the selection anymore, so it's possible that we get it before the
older JS code finished running. However, even calling selectedText() from a JS
callback didn't seem to help...

Since has_selection also is flawed and it taking a callback would make code more
complex as well, let's just assume there is a selection if the text is not
empty. In fact, that is exactly what QtWebEngine does for hasSelection anyways!

Fixes #3523

qutebrowser/browser/browsertab.py

@@ -392,9 +392,6 @@ class AbstractCaret(QObject):
     def drop_selection(self):
         raise NotImplementedError
 
-    def has_selection(self):
-        raise NotImplementedError
-
     def selection(self, html=False, callback=None):
         raise NotImplementedError
 

qutebrowser/browser/commands.py

@@ -853,7 +853,7 @@ class CommandDispatcher:
             what = 'URL'  # For printing
         elif what == 'selection':
             def _selection_callback(s):
-                if not self._current_widget().caret.has_selection() or not s:
+                if not s:
                     message.info("Nothing to yank")
                     return
                 self._yank_to_target(s, sel, what, keep)
@@ -1267,7 +1267,7 @@ class CommandDispatcher:
             env['QUTE_TITLE'] = self._tabbed_browser.page_title(idx)
 
         tab = self._tabbed_browser.currentWidget()
-        if tab is not None and tab.caret.has_selection():
+        if tab is not None:
             env['QUTE_SELECTED_TEXT'] = selection
             try:
                 env['QUTE_SELECTED_HTML'] = tab.caret.selection(html=True)

qutebrowser/browser/webengine/webenginetab.py

@@ -289,24 +289,15 @@ class WebEngineCaret(browsertab.AbstractCaret):
     def drop_selection(self):
         self._js_call('dropSelection')
 
-    def has_selection(self):
-        if qtutils.version_check('5.10'):
-            return self._widget.hasSelection()
-        else:
-            # WORKAROUND for
-            # https://bugreports.qt.io/browse/QTBUG-53134
-            return True
-
     def selection(self, html=False, callback=None):
         if html:
             raise browsertab.UnsupportedOperationError
-        if qtutils.version_check('5.10'):
+        # Not using selectedText() as WORKAROUND for
-            callback(self._widget.selectedText())
-        else:
-            # WORKAROUND for
         # https://bugreports.qt.io/browse/QTBUG-53134
-            self._tab.run_js_async(
+        # Even on Qt 5.10 selectedText() seems to work poorly, see
-                javascript.assemble('caret', 'getSelection'), callback)
+        # https://github.com/qutebrowser/qutebrowser/issues/3523
+        self._tab.run_js_async(javascript.assemble('caret', 'getSelection'),
+                               callback)
 
     def _follow_selected_cb(self, js_elem, tab=False):
         """Callback for javascript which clicks the selected element.

qutebrowser/browser/webkit/webkittab.py

@@ -360,9 +360,6 @@ class WebKitCaret(browsertab.AbstractCaret):
     def drop_selection(self):
         self._widget.triggerPageAction(QWebPage.MoveToNextChar)
 
-    def has_selection(self):
-        return self._widget.hasSelection()
-
     def selection(self, html=False, callback=False):
         callback(self._selection(html))
 
@@ -373,8 +370,6 @@ class WebKitCaret(browsertab.AbstractCaret):
             return self._widget.selectedText()
 
     def follow_selected(self, *, tab=False):
-        if not self.has_selection():
-            return
         if QWebSettings.globalSettings().testAttribute(
                 QWebSettings.JavascriptEnabled):
             if tab:
@@ -383,6 +378,8 @@ class WebKitCaret(browsertab.AbstractCaret):
                 'window.getSelection().anchorNode.parentNode.click()')
         else:
             selection = self._selection(html=True)
+            if not selection:
+                return
             try:
                 selected_element = xml.etree.ElementTree.fromstring(
                     '<html>{}</html>'.format(selection)).find('a')