bug#28855: 26.0.90; display-line-numbers-mode does not respect (line|wrap)-prefix '(space :align-to N) text property

[Paul Rankin <hello@paulwrankin.com>]

On Tue, 17 Oct 2017, at 02:04 PM, Eli Zaretskii wrote:
> > :align-to does align to its value, it just doesn't currently update it
> > to account for the space taken by line numbers.

Justifying a bug doesn’t fix it.

> > It's clear that the change I have in mind will solve your specific
> > problem, I just want to hear from others whether it could harm
> > something.
> 
> Btw, in case it wasn't clear: a solution for this is already available --
> use line-number-display-width when computing the value of :align-to.
> Like tabulated-list-mode already does.
> 
> I'm just trying to establish if a more convenient solution could be possible.

Further to the cited discussion, if taken to its logical conclusions, this approach reaches a point of absurdity, e.g.

Three lines with respective :align-to property values of 0, 2 and 4 should appear like this:

    foo
      bar
        baz

However what we get when these lines occur at line 1000 with display-line-numbers-mode enabled is:

    1000 foo
    1001 bar
    1002 baz

Or, given that the line numbers take up a width of 4 characters, and we don’t account for this width, then logically do we now truncate the leading 4 and 2 characters....?

    1000 
    1001 r
    1002 baz