--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/contrib/hgfixes/fix_leftover_imports.py	Sun Aug 08 15:48:58 2010 -0300
@@ -0,0 +1,108 @@
+"Fixer that translates some APIs ignored by the default 2to3 fixers."
+
+# FIXME: This fixer has some ugly hacks. Its main design is based on that of
+# fix_imports, from lib2to3. Unfortunately, the fix_imports framework only
+# changes module names "without dots", meaning it won't work for some changes
+# in the email module/package. Thus this fixer was born. I believe that with a
+# bit more thinking, a more generic fixer can be implemented, but I'll leave
+# that as future work.
+
+from lib2to3.fixer_util import Name
+from lib2to3.fixes import fix_imports
+
+# This maps the old names to the new names. Note that a drawback of the current
+# design is that the dictionary keys MUST have EXACTLY one dot (.) in them,
+# otherwise things will break. (If you don't need a module hierarchy, you're
+# better of just inherit from fix_imports and overriding the MAPPING dict.)
+
+MAPPING = {'email.Utils': 'email.utils',
+           'email.Errors': 'email.errors',
+           'email.Header': 'email.header',
+           'email.Parser': 'email.parser',
+           'email.Encoders': 'email.encoders',
+           'email.MIMEText': 'email.mime.text',
+           'email.MIMEBase': 'email.mime.base',
+           'email.Generator': 'email.generator',
+           'email.MIMEMultipart': 'email.mime.multipart',
+}
+
+def alternates(members):
+    return "(" + "|".join(map(repr, members)) + ")"
+
+def build_pattern(mapping=MAPPING):
+    packages = {}
+    for key in mapping:
+        # What we are doing here is the following: with dotted names, we'll
+        # have something like package_name <trailer '.' module>. Then, we are
+        # making a dictionary to copy this structure. For example, if
+        # mapping={'A.B': 'a.b', 'A.C': 'a.c'}, it will generate the dictionary
+        # {'A': ['b', 'c']} to, then, generate something like "A <trailer '.'
+        # ('b' | 'c')".
+        name = key.split('.')
+        prefix = name[0]
+        if prefix in packages:
+            packages[prefix].append(name[1:][0])
+        else:
+            packages[prefix] = name[1:]
+
+    mod_list = ' | '.join(["'%s' '.' ('%s')" %
+        (key, "' | '".join(packages[key])) for key in packages])
+    mod_list = '(' + mod_list + ' )'
+    bare_names = alternates(mapping.keys())
+
+    yield """name_import=import_name< 'import' module_name=dotted_name< %s > >
+          """ % mod_list
+
+    yield """name_import=import_name< 'import'
+            multiple_imports=dotted_as_names< any*
+            module_name=dotted_name< %s >
+            any* >
+            >""" % mod_list
+
+    packs = ' | '.join(["'%s' trailer<'.' ('%s')>" % (key,
+               "' | '".join(packages[key])) for key in packages])
+
+    yield "power< package=(%s) trailer<'.' any > any* >" % packs
+
+class FixLeftoverImports(fix_imports.FixImports):
+    # We want to run this fixer after fix_import has run (this shouldn't matter
+    # for hg, though, as setup3k prefers to run the default fixers first)
+    mapping = MAPPING
+
+    def build_pattern(self):
+        return "|".join(build_pattern(self.mapping))
+
+    def transform(self, node, results):
+        # Mostly copied from fix_imports.py
+        import_mod = results.get("module_name")
+        if import_mod:
+            try:
+                mod_name = import_mod.value
+            except AttributeError:
+                # XXX: A hack to remove whitespace prefixes and suffixes
+                mod_name = str(import_mod).strip()
+            new_name = self.mapping[mod_name]
+            import_mod.replace(Name(new_name, prefix=import_mod.prefix))
+            if "name_import" in results:
+                # If it's not a "from x import x, y" or "import x as y" import,
+                # marked its usage to be replaced.
+                self.replace[mod_name] = new_name
+            if "multiple_imports" in results:
+                # This is a nasty hack to fix multiple imports on a line (e.g.,
+                # "import StringIO, urlparse"). The problem is that I can't
+                # figure out an easy way to make a pattern recognize the keys of
+                # MAPPING randomly sprinkled in an import statement.
+                results = self.match(node)
+                if results:
+                    self.transform(node, results)
+        else:
+            # Replace usage of the module.
+            # Now this is, mostly, a hack
+            bare_name = results["package"][0]
+            bare_name_text = ''.join(map(str, results['package'])).strip()
+            new_name = self.replace.get(bare_name_text)
+            prefix = results['package'][0].prefix
+            if new_name:
+                bare_name.replace(Name(new_name, prefix=prefix))
+                results["package"][1].replace(Name(''))
+