futurize: change fix_future_builtins to add only those imports that are needed

Author: edschofield

libfuturize/fixes2/fix_future_builtins.py

@@ -1,28 +1,67 @@
 """
 For the ``future`` package.
 
-Adds this import line:
+Adds this import line::
 
-    from future.builtins import *
+    from future.builtins import XYZ
 
-after any other imports (in an initial block of them).
+for each of the functions XYZ that is used in the module from those in
+future.builtins.
+
+Adds these imports after any other imports (in an initial block of them).
 """
 
-from lib2to3.fixer_base import BaseFix
+from __future__ import unicode_literals
+
+from lib2to3 import fixer_base
 from lib2to3.pygram import python_symbols as syms
 from libfuturize.fixer_util import touch_import_top
 
 
-class FixFutureBuiltins(BaseFix):
+"""
+Fixer that changes zip(seq0, seq1, ...) into list(zip(seq0, seq1, ...)
+unless there exists a 'from future_builtins import zip' statement in the
+top-level namespace.
+
+We avoid the transformation if the zip() call is directly contained in
+iter(<>), list(<>), tuple(<>), sorted(<>), ...join(<>), or for V in <>:.
+"""
+
+# Local imports
+from lib2to3.fixer_util import Name, Call, in_special_context
+
+# from future.builtins.iterators import (filter, map, zip)
+# from future.builtins.misc import (ascii, chr, hex, input, isinstance, oct, open)
+# from future.builtins.backports import (bytes, int, range, round, str, super)
+
+replaced_builtins = '''filter map zip
+                       ascii chr hex input isinstance oct open bytes int range
+                       bytes int range round str super'''.split()
+
+expression = '|'.join(["name='{}'".format(name) for name in replaced_builtins])
+
+
+class FixFutureBuiltins(fixer_base.BaseFix):
     BM_compatible = True
-    PATTERN = "file_input"
-    run_order = 7
-
-    def match(self, node):
-        if node.type == syms.file_input:
-            return True
-        return False
-    
+    run_order = 8
+
+    # Example:
+    # PATTERN = """
+    #           power<
+    #              (name='print'|name='input'|name='raw_input') trailer< '(' args=[any] ')' >
+    #           rest=any* >
+    #           """
+
+    PATTERN = """
+              power<
+                 ({}) trailer< '(' args=[any] ')' >
+              rest=any* >
+              """.format(expression)
+
     def transform(self, node, results):
-        touch_import_top(u'future.builtins', u'*', node)
+        name = results["name"]
+        touch_import_top(u'future.builtins', name.value, node)
+        # name.replace(Name(u"input", prefix=name.prefix))
+
+
 

libfuturize/main.py

@@ -185,20 +185,21 @@ def main(args=None):
     # the current state of each module. (This can simplify testing, and can
     # reduce the need to think about Py2 compatibility when editing the code
     # further.)
-    explicit = set()
+    extra_fixes = set()
     if options.all_imports:
         prefix = 'libfuturize.fixes2.'
         if options.stage1:
-            explicit.add(prefix +
+            extra_fixes.add(prefix +
                             'fix_add__future__imports_except_unicode_literals')
         else:
             # In case the user hasn't run stage1 for some reason:
-            explicit.add(prefix + 'fix_add__future__imports')
-            explicit.add(prefix + 'fix_add_future_standard_library_import')
+            extra_fixes.add(prefix + 'fix_add__future__imports')
+            extra_fixes.add(prefix + 'fix_add_future_standard_library_import')
+            extra_fixes.add(prefix + 'fix_add_all_future_builtins')
 
-    fixer_names = avail_fixes | explicit - unwanted_fixes
+    fixer_names = avail_fixes | extra_fixes - unwanted_fixes
 
-    rt = StdoutRefactoringTool(sorted(fixer_names), flags, explicit,
+    rt = StdoutRefactoringTool(sorted(fixer_names), flags, set(),
                                options.nobackups, not options.no_diffs)
 
     # Refactor all files and directories passed as arguments