python: Add __future__ imports for python 3 compatibility

Except for src/ext, which we may not want to modify.

Closes ticket 32732.

contrib/client-tools/tor-resolve.py

 #!/usr/bin/python
 
+# Future imports for Python 2.7, mandatory in 3.0
+from __future__ import division
+from __future__ import print_function
+from __future__ import unicode_literals
+
 import socket
 import struct
 import sys

scripts/codegen/fuzzing_include_am.py

 #!/usr/bin/python
 
+# Future imports for Python 2.7, mandatory in 3.0
+from __future__ import division
+from __future__ import print_function
+from __future__ import unicode_literals
+
 FUZZERS = """
 	consensus
 	descriptor

scripts/codegen/gen_server_ciphers.py

@@ -8,6 +8,11 @@
 #
 # Run it on all the files in your openssl include directory.
 
+# Future imports for Python 2.7, mandatory in 3.0
+from __future__ import division
+from __future__ import print_function
+from __future__ import unicode_literals
+
 import re
 import sys
 

scripts/codegen/get_mozilla_ciphers.py

@@ -10,6 +10,11 @@
 # It takes two arguments: the location of a firefox source directory, and the
 # location of an openssl source directory.
 
+# Future imports for Python 2.7, mandatory in 3.0
+from __future__ import division
+from __future__ import print_function
+from __future__ import unicode_literals
+
 import os
 import re
 import sys

scripts/codegen/makedesc.py

@@ -9,6 +9,11 @@
 # I've used this to make inputs for unit tests.  I wouldn't suggest
 # using it for anything else.
 
+# Future imports for Python 2.7, mandatory in 3.0
+from __future__ import division
+from __future__ import print_function
+from __future__ import unicode_literals
+
 import base64
 import binascii
 import ctypes

scripts/maint/add_c_file.py

@@ -9,6 +9,11 @@
    % add_c_file.py ./src/feature/dirauth/ocelot.c
 """
 
+# Future imports for Python 2.7, mandatory in 3.0
+from __future__ import division
+from __future__ import print_function
+from __future__ import unicode_literals
+
 import os
 import re
 import time

scripts/maint/annotate_ifdef_directives.py

@@ -57,6 +57,11 @@ Note that only #else and #endif lines are annotated.  Existing comments
 on those lines are removed.
 """
 
+# Future imports for Python 2.7, mandatory in 3.0
+from __future__ import division
+from __future__ import print_function
+from __future__ import unicode_literals
+
 import re
 
 # Any block with fewer than this many lines does not need annotations.

scripts/maint/checkIncludes.py

@@ -5,6 +5,11 @@
 # functionality.  This is a stub file that exists so that older git
 # hooks will know where to look.
 
+# Future imports for Python 2.7, mandatory in 3.0
+from __future__ import division
+from __future__ import print_function
+from __future__ import unicode_literals
+
 import sys, os
 
 dirname = os.path.split(sys.argv[0])[0]

scripts/maint/format_changelog.py

@@ -9,7 +9,11 @@
 # To run it, pipe a section of the changelog (starting with "Changes
 # in Tor 0.x.y.z-alpha" through the script.)
 
+# Future imports for Python 2.7, mandatory in 3.0
+from __future__ import division
 from __future__ import print_function
+from __future__ import unicode_literals
+
 import os
 import re
 import sys

scripts/maint/lintChanges.py

 #!/usr/bin/python
 
+# Future imports for Python 2.7, mandatory in 3.0
+from __future__ import division
 from __future__ import print_function
-from __future__ import with_statement
+from __future__ import unicode_literals
+
 import sys
 import re
 import os

scripts/maint/locatemissingdoxygen.py

@@ -7,6 +7,11 @@
   to highlight the undocumented stuff.
 """
 
+# Future imports for Python 2.7, mandatory in 3.0
+from __future__ import division
+from __future__ import print_function
+from __future__ import unicode_literals
+
 import os
 import re
 import shutil

scripts/maint/practracker/includes.py

@@ -19,8 +19,10 @@
    Advisory .may_include files only result in warnings, rather than errors.
 """
 
-
+# Future imports for Python 2.7, mandatory in 3.0
+from __future__ import division
 from __future__ import print_function
+from __future__ import unicode_literals
 
 import fnmatch
 import os

scripts/maint/practracker/metrics.py

@@ -4,6 +4,11 @@
 # These are currently ad-hoc string operations and regexps.
 # We might want to use a proper static analysis library in the future, if we want to get more advanced metrics.
 
+# Future imports for Python 2.7, mandatory in 3.0
+from __future__ import division
+from __future__ import print_function
+from __future__ import unicode_literals
+
 import re
 
 def get_file_len(f):

scripts/maint/practracker/practracker.py

@@ -19,7 +19,10 @@ problems in the Tor source, use the --regen flag:
   $ python3 --regen ./scripts/maint/practracker/practracker.py .
 """
 
+# Future imports for Python 2.7, mandatory in 3.0
+from __future__ import division
 from __future__ import print_function
+from __future__ import unicode_literals
 
 import os, sys
 

scripts/maint/practracker/practracker_tests.py

@@ -2,6 +2,11 @@
 
 """Some simple tests for practracker metrics"""
 
+# Future imports for Python 2.7, mandatory in 3.0
+from __future__ import division
+from __future__ import print_function
+from __future__ import unicode_literals
+
 import unittest
 
 try:

scripts/maint/practracker/problem.py

@@ -7,7 +7,10 @@ problem is worse than a registered exception so that it only warns when things
 get worse.
 """
 
+# Future imports for Python 2.7, mandatory in 3.0
+from __future__ import division
 from __future__ import print_function
+from __future__ import unicode_literals
 
 import os.path
 import re

scripts/maint/practracker/util.py

+# Future imports for Python 2.7, mandatory in 3.0
+from __future__ import division
+from __future__ import print_function
+from __future__ import unicode_literals
+
 import os
 
 # We don't want to run metrics for unittests, automatically-generated C files,

scripts/maint/rectify_include_paths.py

 #!/usr/bin/python
 
+# Future imports for Python 2.7, mandatory in 3.0
+from __future__ import division
+from __future__ import print_function
+from __future__ import unicode_literals
+
 import os
 import os.path
 import re

scripts/maint/redox.py

@@ -29,6 +29,14 @@
 #     "mv fname.c.newdoc fname.c".  Otherwise, you'll need to merge
 #     the parts you like by hand.
 
+# Future imports for Python 2.7, mandatory in 3.0
+from __future__ import division
+from __future__ import print_function
+from __future__ import unicode_literals
+
+import re
+import sys
+
 # Which files should we ignore warning from?  Mostly, these are external
 # files that we've snarfed in from somebody else, whose C we do no intend
 # to document for them.
@@ -52,9 +60,6 @@ ADD_DOCDOCS_TO_TYPES += [ 'variable', ]
 # ====================
 # The rest of this should not need hacking.
 
-import re
-import sys
-
 KINDS = [ "type", "field", "typedef", "define", "function", "variable",
           "enumeration" ]
 

scripts/maint/rename_c_identifier.py

@@ -11,6 +11,11 @@ Helpful script to replace one or more C identifiers, and optionally
 generate a commit message explaining what happened.
 """
 
+# Future imports for Python 2.7, mandatory in 3.0
+from __future__ import division
+from __future__ import print_function
+from __future__ import unicode_literals
+
 import argparse
 import fileinput
 import os