Issue #13930: Adds ability for 2to3 to write its output to a different

directory tree instead of overwriting the input files.  Adds three command
line options: -o/--output-dir, -W/--write-unchanged-files and --add-suffix.

Feature backports into stable release branches for 2to3 are allowed by
a special exemption:
 http://mail.python.org/pipermail/python-dev/2011-December/115089.html

1 files changed, 13 insertions, 7 deletions

diff --git a/Lib/lib2to3/refactor.py b/Lib/lib2to3/refactor.py
index ae5e40f..7cd034a 100644
--- a/Lib/lib2to3/refactor.py
+++ b/Lib/lib2to3/refactor.py
@@ -173,7 +173,8 @@ class FixerError(Exception):
 
 class RefactoringTool(object):
 
-    _default_options = {"print_function" : False}
+    _default_options = {"print_function" : False,
+                        "write_unchanged_files" : False}
 
     CLASS_PREFIX = "Fix" # The prefix for fixer classes
     FILE_PREFIX = "fix_" # The prefix for modules with a fixer within
@@ -195,6 +196,10 @@ class RefactoringTool(object):
             self.grammar = pygram.python_grammar_no_print_statement
         else:
             self.grammar = pygram.python_grammar
+        # When this is True, the refactor*() methods will call write_file() for
+        # files processed even if they were not changed during refactoring. If
+        # and only if the refactor method's write parameter was True.
+        self.write_unchanged_files = self.options.get("write_unchanged_files")
         self.errors = []
         self.logger = logging.getLogger("RefactoringTool")
         self.fixer_log = []
@@ -341,13 +346,13 @@ class RefactoringTool(object):
         if doctests_only:
             self.log_debug("Refactoring doctests in %s", filename)
             output = self.refactor_docstring(input, filename)
-            if output != input:
+            if self.write_unchanged_files or output != input:
                 self.processed_file(output, filename, input, write, encoding)
             else:
                 self.log_debug("No doctest changes in %s", filename)
         else:
             tree = self.refactor_string(input, filename)
-            if tree and tree.was_changed:
+            if self.write_unchanged_files or (tree and tree.was_changed):
                 # The [:-1] is to take off the \n we added earlier
                 self.processed_file(str(tree)[:-1], filename,
                                     write=write, encoding=encoding)
@@ -386,13 +391,13 @@ class RefactoringTool(object):
         if doctests_only:
             self.log_debug("Refactoring doctests in stdin")
             output = self.refactor_docstring(input, "<stdin>")
-            if output != input:
+            if self.write_unchanged_files or output != input:
                 self.processed_file(output, "<stdin>", input)
             else:
                 self.log_debug("No doctest changes in stdin")
         else:
             tree = self.refactor_string(input, "<stdin>")
-            if tree and tree.was_changed:
+            if self.write_unchanged_files or (tree and tree.was_changed):
                 self.processed_file(str(tree), "<stdin>", input)
             else:
                 self.log_debug("No changes in stdin")
@@ -502,7 +507,7 @@ class RefactoringTool(object):
     def processed_file(self, new_text, filename, old_text=None, write=False,
                        encoding=None):
         """
-        Called when a file has been refactored, and there are changes.
+        Called when a file has been refactored and there may be changes.
         """
         self.files.append(filename)
         if old_text is None:
@@ -513,7 +518,8 @@ class RefactoringTool(object):
         self.print_output(old_text, new_text, filename, equal)
         if equal:
             self.log_debug("No changes to %s", filename)
-            return
+            if not self.write_unchanged_files:
+                return
         if write:
             self.write_file(new_text, filename, old_text, encoding)
         else: