trace: don't use a tempfile in apply_fixers anymore

my2to3/fixes/__init__.py

-import lib2to3.fixer_base
-import os
-
-
-class BaseFix(lib2to3.fixer_base.BaseFix):
-  def start_tree(self, tree, filename):
-    # See my2to3.trace.apply_fixers
-    sep = '-' * 5 # Arbitrary
-    if sep in filename:
-      filename = filename.split(sep, 1)[1].replace(sep, os.sep)
-
-    super(BaseFix, self).start_tree(tree, filename)

my2to3/fixes/fix_division_support.py

 import __builtin__
 from collections import defaultdict
+from lib2to3.fixer_base import BaseFix
 import lib2to3.pgen2
 from lib2to3.pygram import python_symbols as syms
 from lib2to3.pytree import Leaf, Node
@@ -7,7 +8,6 @@ import os
 import re
 
 from my2to3.util import add_future
-from my2to3.fixes import BaseFix
 
 trace_file_match = re.compile(r"^(.*)\|(.*)\|(.*) <type '(.*)'> / <type '(.*)'>$").match
 

my2to3/fixes/fix_division_trace.py

 # https://lab.nexedi.com/nexedi/erp5/snippets/475
 from collections import defaultdict
 import inspect
+from lib2to3.fixer_base import BaseFix
 import lib2to3.fixer_util
 import lib2to3.pgen2
 from lib2to3.pygram import python_symbols as syms
 from lib2to3.pytree import Node
 
-from my2to3.fixes import BaseFix
 from my2to3.trace import create_table, register_tracing_function
 from my2to3.util import parse_type
 

my2to3/fixes/fix_nested_except_trace.py

+from lib2to3.fixer_base import BaseFix
 from lib2to3.pygram import python_symbols as syms
 
-from my2to3.fixes import BaseFix
 from my2to3.trace import create_table
 
 

my2to3/trace.py

-import __builtin__, imp, os, sqlite3, sys, tempfile, types
+import __builtin__, imp, os, sqlite3, sys, types
 
+from lib2to3.pgen2 import tokenize
 from lib2to3.refactor import get_fixers_from_package, RefactoringTool
 
 database = "traces.db"
@@ -44,20 +45,16 @@ def get_fixers():
 
 
 def apply_fixers(string, name):
+  # This function is inspired by refactoring_tool.refactor_file
+
   refactoring_tool = RefactoringTool(fixer_names=get_fixers())
-  # A temporary file is used to enjoy the benefits of
-  # refactoring_tool.refactor_file (unlike directly using
-  # refactoring_tool.refactor_string).
-  #
-  # XXX: We add the original name via the suffix. Fixers are able to handle this
-  # (see my2to3.fixes.BaseFix). Let's find a better way.
-  sep = '-' * 5 # Arbitrary
-  with tempfile.NamedTemporaryFile(suffix=sep + name.replace(os.sep, sep)) as f:
-    f.write(string)
-    f.flush()
-    refactoring_tool.refactor_file(f.name, write=True)
-    f.seek(0)
-    return f.read()
+  encoding = tokenize.detect_encoding(lambda: string)[0]
+
+  string += "\n" # Silence certain parse errors
+  s = string.decode(encoding)
+  s = refactoring_tool.refactor_string(s, name)
+  # The [:-1] is to take off the \n we added earlier
+  return unicode(s)[:-1].encode(encoding)
 
 
 init_py = '__init__' + os.extsep + 'py'