bug#19812: 24.4; suggest `shell-mode' not interactive

[Lars Ingebrigtsen <larsi@mouse.gnus.org>]

Eli Zaretskii <eliz@gnu.org> writes:

>> As you point out, there's a lot of modes that only make sense in certain
>> limited contexts, and having them be interactive isn't very helpful.
>> I'm not sure it's that much of a problem in general, but it is a
>> particular an issue with `shell-mode', since I'd guess that a lot of
>> people type that instead of `M-x shell-script-mode' when starting to
>> write new shell scripts.
>> 
>> The following fixes this particular issue.  Would something like this be
>> welcome?
>
> Are there no valid use cases where invoking shell-mode interactively
> makes sense?  If there are such use cases, we cannot disallow them
> now.

If I read the comments correctly, nobody had a use case for using `M-x
shell-mode'.  It was proposed that it could possibly be useful for
working in log files and the like, but that shell-mode doesn't currently
actually support that, so I went ahead and applied the patch to disable
the interactive use of the mode.

If this leads to problems for anybody, feel free to revert the commit.

-- 
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