bug#18308: 24.4.50; Info viewer cannot follow menu entry for '(texinfo) @- @hyphenation'

["Vincent Belaïche" <Vincent.b.1@hotmail.fr>]

Resent With cc to 18308@debbugs.gnu.org

Feedback inserted below...

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> Date: Thu, 21 Aug 2014 17:12:13 +0300
> From: eliz@gnu.org
> Subject: Re: bug#18308: 24.4.50; Info viewer cannot follow menu entry for '(texinfo) @- @hyphenation'
> To: vincent.b.1@hotmail.fr
> CC: 18308@debbugs.gnu.org
>
> > From: Vincent Belaïche <vincent.b.1@hotmail.fr>
> > Date: Thu, 21 Aug 2014 10:45:11 +0200
> > Cc: Vincent Belaïche <vincent.b.1@hotmail.fr>
> >
> > In texinfo manual, info node `(texinfo) Breaks', if I set pointer on
> > third menu entry and type RET, the I get message:
> >
> > user-error: No such node or anchor: @- @hyphenation
>
> This is not an Emacs bug, it's a bug in the Texinfo manual. For some
> reason, it sometimes refers to this node as "@- @hyphenation" (with 2
> spaces), and sometimes as "@- @hyphenation" (with only 1 space). The
> menu uses the former, while the node name uses the latter. So Emacs
> cannot find the node.
>
> > However, if I type '3', then I go to the wanted node.
>
> That's because the command bound to '3' normalizes the whitespace in
> the node name. I don't know why it does that, but that code exists
> since about forever.
>
> Maybe we could consider normalizing the whitespace in the 1st case as
> well, but that's just a work around for a buggy manual.


I would not say that this is a bug in the manual --- manuals are written
by human beings, and human beings are living creatures, just like bugs
are ;-) .

Rather, I think that this is a bug in the texinfo info compiler that
should:

1) produce some warning message, as a matter of fact the manual is not
   consistent with info node `(texinfo) Node Line Requirements' --- see
   below why

2) collapse multiple spaces to a single space in node names as the info
   file is produced.

In info node "(texinfo) Node Line Requirements", there is this
statement:


-----------------------------------------------------------------------
     Spaces before and after names on the '@node' line are ignored.
     Multiple whitespace characters "inside" a name are collapsed to a
     single space.  For example:

          @node  foo bar,
          @node foo bar ,
          @node foo  bar,
          @node  foo  bar ,

     all define the same node, namely 'foo bar'.  References to the node
     should all use that name, with no leading or trailing spaces a
     single internal space.
-----------------------------------------------------------------------

It seems that there is a typo in this node and the end of last sentence
should read: "with no leading or trailing spaces *AND* a single internal
space". Anyway, because the menu entry is a REFERENCE to the node, then
it should use this name with a single internal space. Because it does
not, the manual is not conformant to this spec.

So, I think that you treate the EMACS info viewer bug as you like ---
either close it, or think that you should make the info viewer more
robust by collapsing multiple internal spaces to a single space like the
'3' command does. My personal feeling is that you should robustify the
info viewer.

On my side I will open a bug Texinfo project to refer to this one and
ask for compiler to handle point 1) and 2) above and correct the typo in
the manual.

  Vincent.