bug#65631: Xref updates stack in case of error

[Dmitry Gutov]

Hi!

On 30/08/2023 20:16, Juri Linkov wrote:
> > > 1. move point to any word
> > > 2. type 'M-.' (xref-find-definitions)
> > > 3. an error is displayed correctly "No definitions found for: This"
> > >
> > > But the problem is that an unrecognized word is added to the xref stack.
> > > So the context menu shows "Go Back", and 'M-,' (xref-go-back) goes back
> > > to that word.
> > FWIW, I'm not sure this is necessarily a bug.  It looks like a bug in
> > your case, because you deliberately tricked Xref into using a word
> > that is definitely not a program symbol.  But that is not the case in
> > a more reasonable situation, where point is on a symbol, but for some
> > reason the symbol's definition is not found, e.g., because the TAGS
> > table needs to be regenerated.
> In case of error, point doesn't move.  So there is no need to go back.

At this point, I was kind of feeling that this is a known-but-tolerated 
behavior (that some might already be relying on, also known as "spacebar 
heater" effect), but if it's still annoying, let's see about a fix.

How's the attached patch?

xref--push-markers.diff
Description: Text Data