This patch changes the default behaviour of the builtin charmap

codec to not apply Latin-1 mappings for keys which are not found
in the mapping dictionaries, but instead treat them as undefined
mappings.

The patch was originally written by Martin v. Loewis with some
additional (cosmetic) changes and an updated test script
by Marc-Andre Lemburg.

The standard codecs were recreated from the most current files
available at the Unicode.org site using the Tools/scripts/gencodec.py
tool.

This patch closes the bugs #116285 and #119960.

1 files changed, 15 insertions, 0 deletions

diff --git a/Lib/codecs.py b/Lib/codecs.py
index fca0f8e287..993113752e 100644
--- a/Lib/codecs.py
+++ b/Lib/codecs.py
@@ -539,6 +539,21 @@ def EncodedFile(file, data_encoding, file_encoding=None, errors='strict'):
     sr.file_encoding = file_encoding
     return sr
 
+### Helpers for charmap-based codecs
+
+def make_identity_dict(rng):
+
+    """ make_identity_dict(rng) -> dict
+
+        Return a dictionary where elements of the rng sequence are
+        mapped to themselves.
+        
+    """
+    res = {}
+    for i in rng:
+        res[i]=i
+    return res
+
 ### Tests
 
 if __name__ == '__main__':