Move python check to separate file

qutebrowser/app.py

@@ -18,8 +18,9 @@
 """Initialization of qutebrowser and application-wide things."""
 
 ### Things we want to do before normal imports ###
+from qutebrowser.utils.checkpyver import check_python_version
+check_python_version()
 import qutebrowser.utils.earlyinit as earlyinit
-earlyinit.check_python_version()
 earlyinit.init_faulthandler()
 earlyinit.fix_harfbuzz()
 earlyinit.check_pyqt_core()

qutebrowser/utils/checkpyver.py

@@ -0,0 +1,37 @@
+# This file is part of qutebrowser.
+#
+# qutebrowser is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# qutebrowser is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with qutebrowser.  If not, see <http://www.gnu.org/licenses/>.
+
+"""Check if qutebrowser is run with the correct python version.
+
+This should import and run fine with both python2 and python3.
+"""
+
+import sys
+
+
+# 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
+# to stderr.
+def check_python_version():
+    """Check if correct python version is run."""
+    if sys.hexversion < 0x03030000:
+        # 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()
+        sys.exit(1)

qutebrowser/utils/earlyinit.py

@@ -15,28 +15,17 @@
 
 """Things which need to be done really early (e.g. before importing Qt).
 
-These functions are supposed to get called in the order they're in this file.
-At the very start, we aren't even sure about the Python version used, so we
-import more exotic modules later.
+At this point we can be sure we have all python 3.3 features available.
 """
 
 import os
 import sys
+import faulthandler
+import textwrap
+import traceback
+from signal import SIGUSR1
 
 
-# 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
-# to stdout.
-def check_python_version():
-    """Check if correct python version is run."""
-    if sys.hexversion < 0x03030000:
-        print("Fatal error: At least Python 3.3 is required to run "
-              "qutebrowser, but {} is installed!".format(
-                  '.'.join(map(str, sys.version_info[:3]))))
-        sys.exit(1)
-
-
-# At this point we can be sure we have all python 3.3 features available.
 # Now we initialize the faulthandler as early as possible, so we theoretically
 # could catch segfaults occuring later.
 def init_faulthandler():
@@ -44,8 +33,6 @@ def init_faulthandler():
 
     This print a nice traceback on segfauls.
     """
-    import faulthandler
-    from signal import SIGUSR1
     if sys.stderr is not None:
         # When run with pythonw.exe, sys.stderr can be None:
         # https://docs.python.org/3/library/sys.html#sys.__stderr__
@@ -83,8 +70,6 @@ def fix_harfbuzz():
 # console.
 def check_pyqt_core():
     """Check if PyQt core is installed."""
-    import textwrap
-    import traceback
     try:
         import PyQt5.QtCore  # pylint: disable=unused-variable
     except ImportError:
@@ -107,9 +92,9 @@ def check_pyqt_core():
 
             For other distributions:
                 Check your package manager for similiarly named packages.
-            """).strip())
+            """).strip(), file=sys.stderr)
         if '--debug' in sys.argv:
-            print()
+            print(file=sys.stderr)
             traceback.print_exc()
         sys.exit(1)
 
@@ -119,8 +104,6 @@ def check_pyqt_core():
 def check_pyqt_webkit():
     """Check if PyQt WebKit is installed."""
     from PyQt5.QtWidgets import QApplication, QMessageBox
-    import textwrap
-    import traceback
     try:
         import PyQt5.QtWebKit  # pylint: disable=unused-variable
     except ImportError:
@@ -140,8 +123,9 @@ def check_pyqt_webkit():
                 Check your package manager for similiarly named packages.
             """).strip())
         if '--debug' in sys.argv:
-            print()
+            print(file=sys.stderr)
             traceback.print_exc()
         msgbox.resize(msgbox.sizeHint())
         msgbox.exec_()
         app.quit()
+        sys.exit(1)