Add some more init checks and use Tk for errors

qutebrowser/qutebrowser.py

@@ -15,14 +15,27 @@
 # You should have received a copy of the GNU General Public License
 # along with qutebrowser.  If not, see <http://www.gnu.org/licenses/>.
 
-"""Early initialization and main entry pint."""
+"""Early initialization and main entry point."""
 
-
-from argparse import ArgumentParser
+import sys
 
 import qutebrowser
-from qutebrowser.utils.checkpyver import check_python_version
+try:
+    from qutebrowser.utils.checkpyver import check_python_version
+except ImportError:
+    try:
+        # python2
+        from .utils.checkpyver import check_python_version
+    except (SystemError, ValueError):
+        # Import without module - SystemError on Python3, ValueError (?!?) on
+        # Python2
+        sys.stderr.write("Please don't run this script directly, do something "
+                         "like   python3 -m qutebrowser   instead.\n")
+        sys.stderr.flush()
+        sys.exit(100)
 check_python_version()
+
+from argparse import ArgumentParser
 import qutebrowser.utils.earlyinit as earlyinit
 
 

qutebrowser/utils/checkpyver.py

@@ -22,6 +22,18 @@ This should import and run fine with both python2 and python3.
 
 import sys
 
+try:
+    # Python3
+    from tkinter import Tk, messagebox
+except ImportError:
+    try:
+        # Python2
+        from Tkinter import Tk
+        import tkMessageBox as messagebox
+    except ImportError:
+        # Some Python without Tk
+        Tk = None
+
 
 # First we check the version of Python. This code should run fine with python2
 # and python3. We don't have Qt available here yet, so we just print an error
@@ -32,8 +44,13 @@ def check_python_version():
         # We don't use .format() and print_function here just in case someone
         # still has < 2.6 installed.
         version_str = '.'.join(map(str, sys.version_info[:3]))
-        sys.stderr.write("Fatal error: At least Python 3.3 is required to run "
-                         "qutebrowser, but " + version_str + " is "
-                         "installed!\n")
-        sys.stderr.flush()
+        text = ("At least Python 3.3 is required to run qutebrowser, but " +
+                version_str + " is installed!\n")
+        if Tk:
+            root = Tk()
+            root.withdraw()
+            messagebox.showerror("qutebrowser: Fatal error!", text)
+        else:
+            sys.stderr.write(text)
+            sys.stderr.flush()
         sys.exit(1)

qutebrowser/utils/earlyinit.py

@@ -25,6 +25,10 @@ import sys
 import faulthandler
 import traceback
 import signal
+try:
+    from tkinter import Tk, messagebox
+except ImportError:
+    Tk = None
 
 
 def _missing_str(name, debian=None, arch=None, windows=None, pip=None):
@@ -175,7 +179,12 @@ def check_pyqt_core():
                                     "or the standalone qutebrowser exe.\n"
                                     "http://www.riverbankcomputing.co.uk/"
                                     "software/pyqt/download5")
-        print(text)
+        if Tk:
+            root = Tk()
+            root.withdraw()
+            messagebox.showerror("qutebrowser: Fatal error!", text)
+        else:
+            print(text, file=sys.stderr)
         if '--debug' in sys.argv:
             print(file=sys.stderr)
             traceback.print_exc()