bug#41860: 27.0.91; Can't use `tabulated-list-(narrow|widen)-current-column' on last column

[Drew Adams]

> > Use command `buffer-menu' and then try to narrow or widen the rightmost
> > column (the file name).  `{' and `}' have no effect (and there isn't
> > even any error message or other feedback).
> 
> The last column has infinite width, so I don't see how you could make
> it wider or narrower.  (I agree that we should consider signaling a
> user-error in this case.)

If the last column always has infinite width then
that's another way of expressing this design bug.

Users should be able to narrow its width - truncate
it, just as they can narrow the width of the other
columns.  That's the point.

> > This is an important use case, especially with a frame or window whose
> > width is made to fit the displayed content.
> 
> This seems to imply that the use case in which this is somehow an
> issue includes more than you've reported.  Can you add to your
> description the minimal configuration that could explain why this
> behavior seemed to be a problem?

There's no separate requirement.  Users should be
able to limit the width of the last column, just
as they can limit the width of any other column.
That's all.

I gave an example, and a recipe for it, using
buffer-menu.  If you want to show the file-name
column with only a limited width, then that
should be possible.  Especially now that we've
added the ability to interactively widen and
narrow column incrementally.

In the buffer list, if you have 10 buffers, and
only two of them are file buffers, and you don't
care to see the entire file names but instead
want to limit the width of that last column, you
should be able to do so.  Instead, it takes up
most of the table, even when you don't need to
see all of it.  You should be able to expand and
contract its width, just as you can for other
columns.

Saying that this is just the way it is, which is
what you seem to be saying, is another way of
reiterating the design limitation that this bug
report reports.

> > This isn't a failing only of
> > `tabulated-list-(narrow|widen)-current-column'.  It's a failing of the
> > current design of `tabulated-list-print-col'.
> 
> Any basis for such general claim?  Which design is at fault here?

Explained in the bug report: `tabulated-list-print-col'
treats the last column specially - it doesn't allow
limiting its width, i.e., truncating it.

;; Truncate labels if necessary (except last column).
                                 ^^^^^^^^^^^^^^^^^^

This is apparently by design - it's currently a design
limitation of t-l-mode, apparently.  It's not a bug
in implementing that design, but an intentional part
of the design.  Or so it seems, not only from the
code but from that comment.

Regardless of my interpretation of where the bug is -
code or design, ` tabulated-list-print-col' or not,
the current limitation is clear.