23.0.60; Bug in BUF_SET_PT

23.0.60; Bug in BUF_SET_PT

[Johan Bockgård]

[Trunk and branch]

There is a problem with BUF_SET_PT (i.e. set_point_both with BUFFER !=
current_buffer).  It moves point in BUFFER, but properties and bindings
are always taken from the current buffer.  (BUF_SET_PT is used in two
places in Emacs, Feval_buffer and Finsert_file_contents; maybe they
should be using BUF_TEMP_SET_PT anyway?  Also, could set_point_both use
DEFAULT_INTERVAL_P instead of NULL_INTERVAL_P?)


-- 
Johan Bockgård

Re: 23.0.60; Bug in BUF_SET_PT

[Johan Bockgård]

bojohan+mail@dd.chalmers.se (Johan Bockgård) writes:

> [Trunk and branch]

Stefan has checked in a fix on the trunk, but the problem exists on the
Emacs 22 branch as well.

> There is a problem with BUF_SET_PT (i.e. set_point_both with BUFFER !=
> current_buffer).  It moves point in BUFFER, but properties and bindings
> are always taken from the current buffer.  (BUF_SET_PT is used in two
> places in Emacs, Feval_buffer and Finsert_file_contents; maybe they
> should be using BUF_TEMP_SET_PT anyway?  Also, could set_point_both use
> DEFAULT_INTERVAL_P instead of NULL_INTERVAL_P?)

-- 
Johan Bockgård

Re: 23.0.60; Bug in BUF_SET_PT

[Stefan Monnier]

>> [Trunk and branch]

> Stefan has checked in a fix on the trunk, but the problem exists on the
> Emacs 22 branch as well.

Like lots of other problems.
Do you have a real case where it introduces real breakage?


        Stefan

Re: 23.0.60; Bug in BUF_SET_PT

[Johan Bockgård]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

>>> [Trunk and branch]
>
>> Stefan has checked in a fix on the trunk, but the problem exists on the
>> Emacs 22 branch as well.
>
> Like lots of other problems.
> Do you have a real case where it introduces real breakage?

Yes, I have run into args-out-of-range errors in revert-buffer (that's
how I found the problem).  It's very rare though.

Debugger entered--Lisp error: (args-out-of-range 720381)
  insert-file-contents("[...]" t nil nil t)
  revert-buffer(nil t)

(If you want to be conservative on the branch, just make the BUF_SET_PT
--> BUF_TEMP_SET_PT change.)

-- 
Johan Bockgård

Re: 23.0.60; Bug in BUF_SET_PT

[Stefan Monnier]

>>>> [Trunk and branch]
>> 
>>> Stefan has checked in a fix on the trunk, but the problem exists on the
>>> Emacs 22 branch as well.
>> 
>> Like lots of other problems.
>> Do you have a real case where it introduces real breakage?

> Yes, I have run into args-out-of-range errors in revert-buffer (that's
> how I found the problem).  It's very rare though.

> Debugger entered--Lisp error: (args-out-of-range 720381)
>   insert-file-contents("[...]" t nil nil t)
>   revert-buffer(nil t)

I expect this to be very rare indeed, since the problem has been around
for ages.

> (If you want to be conservative on the branch, just make the BUF_SET_PT
> --> BUF_TEMP_SET_PT change.)

Of course, that's the only part I'd commit.  But even this will have to
wait for after-22.2.


        Stefan