bpo-43510: Implement PEP 597 opt-in EncodingWarning. (GH-19481)
See [PEP 597](https://www.python.org/dev/peps/pep-0597/).
* Add `-X warn_default_encoding` and `PYTHONWARNDEFAULTENCODING`.
* Add EncodingWarning
* Add io.text_encoding()
* open(), TextIOWrapper() emits EncodingWarning when encoding is omitted and warn_default_encoding is enabled.
* _pyio.TextIOWrapper() uses UTF-8 as fallback default encoding used when failed to import locale module. (used during building Python)
* bz2, configparser, gzip, lzma, pathlib, tempfile modules use io.text_encoding().
* What's new entry
diff --git a/Objects/exceptions.c b/Objects/exceptions.c
index 88e2287..dfa069e 100644
--- a/Objects/exceptions.c
+++ b/Objects/exceptions.c
@@ -2465,6 +2465,13 @@ SimpleExtendsException(PyExc_Warning, BytesWarning,
/*
+ * EncodingWarning extends Warning
+ */
+SimpleExtendsException(PyExc_Warning, EncodingWarning,
+ "Base class for warnings about encodings.");
+
+
+/*
* ResourceWarning extends Warning
*/
SimpleExtendsException(PyExc_Warning, ResourceWarning,
@@ -2592,6 +2599,7 @@ _PyExc_Init(PyInterpreterState *interp)
PRE_INIT(BufferError);
PRE_INIT(Warning);
PRE_INIT(UserWarning);
+ PRE_INIT(EncodingWarning);
PRE_INIT(DeprecationWarning);
PRE_INIT(PendingDeprecationWarning);
PRE_INIT(SyntaxWarning);
@@ -2731,6 +2739,7 @@ _PyBuiltins_AddExceptions(PyObject *bltinmod)
POST_INIT(BufferError);
POST_INIT(Warning);
POST_INIT(UserWarning);
+ POST_INIT(EncodingWarning);
POST_INIT(DeprecationWarning);
POST_INIT(PendingDeprecationWarning);
POST_INIT(SyntaxWarning);