Re: "fake" style requires at least one real match?

[Bart Schaefer <schaefer@xxxxxxxxxxxxxxxx>]

On Nov 5, 11:42pm, Bart Schaefer wrote:
}
} I have no immediate idea what to do about this.  We can't rewrite
} every caller of _description to delta $compstate[nmatches] just
} in case a fake style was used.  And in fact it only matters when
} ONLY the fake matches are added, as the Subject: says ...

I looked through all the functions that call _description and for
the vast majority of them this only matters indirectly to the caller
of the function; that is, the usage is equivalent to

    _description ...
    compadd ...
    return

which means that unless the caller is testing the return value to
decide whether to proceed with another completion, adding fake matches
in _description does not affect anything.  Ignoring for the moment
functions that might appear directly in the 'completer' style, that
leaves the following callers of _description:

_requested and _next_label both ignore the result of _description and
always return zero after calling it.

_alternative does the "right thing" and uses a delta of nmatches to
decide what to return.

_values uses _all_labels and a _next_label loop.

_next_tags redefines _all_labels and _next_label, so I'm going to
ignore it for this purpose.

And then there's _arguments, which has a _tags loop but is a wrapper
that calls back to whatever was passed into it; so there's really no
reasonable way to analyze it.

I think, therefore, the only reasonable thing is to fix _all_labels,
which should by proxy fix _values.  However, it's a little more
complicated than I first thought.

A compounding problem is that we're calling _tilde from _alternative.
_alternative does its own call to _description on line 28, inside
the _tags loop.  Inside _tilde, we start another _tags loop, which
eventually calls _all_labels, which calls _description *again*.  The
fake matches were already added by the first call in _alternative,
so compstate[nmatches] is unchanged and can't work as a test for the
appropriate return value for _all_labels.

For the moment I'm stuck.  Sorry for the play-by-play.  Ideas welcome.

Probably not worth holding up a release, if one is being considered.