RE: bug#10385: e binding in info-mode

[Drew Adams]

> >> There is more trouble when this obsolete feature
> >
> > Since when is it obsolete?
> 
> Since its inception.  Info-edit was never documented in info.texi.
> (And perhaps references to `Info-edit-map' should be removed 
> from elisp.texi)

That a feature is not documented everywhere, or is poor or misguided, does not
mean that it is obsolete.

It is certainly not the case that a command that has been bound to a key
(especially for decades) can be said to be undocumented or invisible/unknown to
users.  Let alone considered obsolete.

Think how many commands and key bindings are not documented in any manual.  They
are certainly not all - or even any of them - "obsolete" since their inception.
Emacs documentation is not limited to manuals, and user awareness of features is
not even limited to any form of documentation.  We provide source code, and that
is the foundation of user communication.

Typically, for a feature or a product to be considered obsolete (officially), it
must first be officially deprecated.  And typically there is a period of time
between deprecation and obsolescence - typically a relatively major release or
more.

Typically, an obsolete feature is no longer supported, and a deprecated feature
is still supported.

For example, it might be decided to announce the deprecation of this option in
24.1, and then make it obsolete in 24.2 (since Emacs point releases are
relatively major).

Given such a decision, it would change from a defcustom to a defvar, or even be
eliminated altogether, in 24.2, depending on what was intended wrt desupport (as
an option or even as a variable).

> > Why does it hurt for this to be a defcustom?
> 
> Think about a novice looking at the available options
> in the Customization group `info'.  It would be a disservice
> to teach them that editing Info nodes is a good idea.

The existence of a user option is not the same thing as suggesting that changing
its value is necessarily a good idea.  We have lots of user options that it
might not be a good idea for a novice, in particular, to customize.  We provide
plenty of rope for users to hang themselves, often even using only Customize.