Re: linum.el: problem (bug ?) fix and improvement

[Eli Zaretskii <eliz@gnu.org>]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Date: Thu, 12 May 2011 10:58:58 -0300
> Cc: emacs-devel@gnu.org
> 
> What we'd like here is for the redisplay to ignore the margin property
> placed on invisible text.

Are you sure?  Only part of a line could be invisible, in which case
it won't be easy to explain why we drop the before-string on the
floor.  I would be uneasy to make such radical changes on behalf of a
single use case.

> This boils down to making Emacs ignore
> `before-string' properties placed at the beginning of invisible text.
> I don't think it's always right to ignore them, tho.

There's explicit code to do it the way we do now:

	  /* If there are before-strings at the start of invisible
	     text, and the text is invisible because of a text
	     property, arrange to show before-strings because 20.x did
	     it that way.  (If the text is invisible because of an
	     overlay property instead of a text property, this is
	     already handled in the overlay code.)  */
	  if (NILP (overlay)
	      && get_overlay_strings (it, it->stop_charpos))
	    {
	      handled = HANDLED_RECOMPUTE_PROPS;
	      it->stack[it->sp - 1].display_ellipsis_p = display_ellipsis_p;
	    }

Just undoing this would be regression from Emacs 20.x.