1 files changed, 43 insertions, 0 deletions
diff --git a/Lib/lib2to3/fixes/fix_zip.py b/Lib/lib2to3/fixes/fix_zip.py
new file mode 100644
index 0000000..e072713
--- /dev/null
+++ b/Lib/lib2to3/fixes/fix_zip.py
@@ -0,0 +1,43 @@
+"""
+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 . import basefix
+from .util import Name, Call, does_tree_import, in_special_context
+
+class FixZip(basefix.BaseFix):
+
+    PATTERN = """
+    power< 'zip' args=trailer< '(' [any] ')' >
+    >
+    """
+
+    def start_tree(self, *args):
+        super(FixZip, self).start_tree(*args)
+        self._future_zip_found = None
+
+    def has_future_zip(self, node):
+        if self._future_zip_found is not None:
+            return self._future_zip_found
+        self._future_zip_found = does_tree_import('future_builtins', 'zip', node)
+        return self._future_zip_found
+
+    def transform(self, node, results):
+        if self.has_future_zip(node):
+            # If a future zip has been imported for this file, we won't
+            # be making any modifications
+            return
+
+        if in_special_context(node):
+            return None
+        new = node.clone()
+        new.set_prefix("")
+        new = Call(Name("list"), [new])
+        new.set_prefix(node.get_prefix())
+        return new