remote: Show an error message when 'Push' fails

"git push" might fail but we provide no indication of this to
the user.  Show a helpful error message when this happens.

Closes #69

Signed-off-by: David Aguilar <davvid@gmail.com>

cola/controllers/remote.py

@@ -209,5 +209,12 @@ def remote_callback():
                 output = self.tr('Already up-to-date.')
             # Force the status to 1 so that we always display the log
             qtutils.log(1, output)
+
+            if status != 0 and action == 'push':
+                message = 'Error pushing to "%s".\n\nPull first?' % remote
+                qtutils.critical('Push Error',
+                                 message=message, details=output)
+
             self.view.accept()
+
         return remote_callback

cola/qtutils.py

@@ -90,6 +90,25 @@ def information(title, message=None):
     parent = QtGui.QApplication.instance().activeWindow()
     QtGui.QMessageBox.information(parent, title, message)
 
+
+def critical(title, message=None, details=None):
+    """Show a warning with the provided title and message."""
+    if message is None:
+        message = title
+    title = tr(title)
+    message = tr(message)
+    parent = QtGui.QApplication.instance().activeWindow()
+    mbox = QtGui.QMessageBox(parent)
+    mbox.setWindowTitle(title)
+    mbox.setTextFormat(QtCore.Qt.PlainText)
+    mbox.setText(message)
+    mbox.setIcon(QtGui.QMessageBox.Critical)
+    mbox.setStandardButtons(QtGui.QMessageBox.Close)
+    mbox.setDefaultButton(QtGui.QMessageBox.Close)
+    if details:
+        mbox.setDetailedText(details)
+    mbox.exec_()
+
 # Register globally with the notifier
 cola.notifier().connect(signals.information, information)