Patch #1357836:

Prevent an invalid memory read from test_coding in case the done flag is set.
In that case, the loop isn't entered.  I wonder if rather than setting
the done flag in the cases before the loop, if they should just exit early.

This code looks like it should be refactored.

Backport candidate (also the early break above if decoding_fgets fails)

Free coding spec (cs) if there was an error to prevent mem leak.
Maybe backport candidate.

[Bugfix seems applicable to 2.4 to me. --amk]

  Bug #1378022, UTF-8 files with a leading BOM crashed the interpreter.
  Also bug #1435487 (dup).

Apply SF patch #1101726: Fix buffer overrun in tokenizer.c when a source file
with a PEP 263 encoding declaration results in long decoded line.

modes like non-interactive modes.  This allows for non-latin-1 users
to write unicode strings directly and sets Japanese users free from
weird manual escaping <wink> in shift_jis environments.
(Reviewed by Martin v. Loewis)

"@ seems the syntax that everybody can hate equally"
Implementation by Mark Russell, from SF #979728.

Remove the usage of PyErr_WarnExplicit() since this could cause
sensitive information from the source files to appear in e.g.
log files.

mark. Added unit test.

Ensure that the 'size' arg is correctly passed to the encoding reader to
prevent buffer overflows.