Re: `save-excursion' defeated by `set-buffer'

["Andreas Röhler" <andreas.roehler@easy-emacs.de>]

Am 11.03.2011 02:28, schrieb Stefan Monnier:
>>> The difference between save-excursion and save-current-buffer is that
>>> the first doesn't just save&restore the current buffer but also "point&
>>> mark".  But if you do `set-buffer' right after save-excursion then most
>>> likely you will change neither point nor mark in the original buffer, so
>>> the extra work performed by save-excursion compared to
>>> save-current-buffer will be useless.
>>> Now that's just a waste of resources but is otherwise harmless.
>>>
>>> Unless of course `blub' is already the current buffer to start with.
>>>
>>> I.e. whether point movement in "..." is undone by save-excursion will
>>> depend dynamically upon whether the current buffer happens to be `blub',
>>> which leads to subtle bugs.  Hence the warning.
>
>> Thanks, this warning goes away if body is wrapped with a let:
>
>> (save-excursion
>>    (let ()
>>      (set-buffer blub)
>>        ...
>>        ))
>
> I see you apparently didn't understand much of what I wrote :-(
>
>
>          Stefan
>

Maybe let's put the question another way:

is there an example, where save-excursion will fail, ie not restore the 
buffer due to a set-buffer afterwards?

Thanks

Andreas