Re: request to revert the chnage of revno 112925

[Paul Eggert]

On 06/19/2013 08:35 AM, Kenichi Handa wrote:
> I'd like to find a better solution, but at first please
> clarify the requirements.

I assume these requirements should be the same for Elisp
files as for other files that Emacs is asked to read;
if not, could this be clarified?

> * What to do with an ASCII file?  Previously find-file for
>   such a file results in undecided-xxx
>   buffer-file-coding-system.  Now it's utf-8-xxx.

To help think this through, could you please explain
the practical consequences of this change?
If I edit a file that's undecided-xxx, and insert
a character that can be encoded either as UTF-8 or
as ISO-2022-JP say, the buffer becomes utf-8-xxx,
right?  So in that scenario there is not much practical
difference.  What scenarios entail significant differences
depending on whether the file is undecided-xxx or utf-8-xxx?

> * What to do with an invalid UTF-8 file.  Previously,
>   find-file detects a proper coding-system for such a file.
>   Now utf-8 is forced and any invalid UTF-8 byte sequences
>   are decoded as raw bytes.

Surely this should be fixed: the file should be decoded
properly, as before.

> * What to do with null byte detection.  Previously, if a
>   *.el file contains a null byte and
>   inhibit-null-byte-detection is nil (the default), it's
>   detected as a binary file.  Now utf-8 is forced regardless
>   of inhibit-null-byte-detection.

I suggest going back to the old behavior (that's the normal
behavior for random files that Emacs edits, right?).
Elisp files normally don't contain null bytes; such files are not
considered to be text files in the POSIXish world.