* bug#17236: undo-only hangs when nils double up
@ 2014-04-10 16:15 Barry OReilly
2014-04-10 17:23 ` Andreas Schwab
2014-04-10 20:30 ` Stefan Monnier
0 siblings, 2 replies; 4+ messages in thread
From: Barry OReilly @ 2014-04-10 16:15 UTC (permalink / raw)
To: 17236
When there are consecutive nils in buffer-undo-list, undo-only can
hang. For example, if buffer-undo-list begins with (nil nil ...), then
the first undo-only succeeds, changes nothing, and inserts an identity
mapping into undo-equiv-table. The second undo-only hangs because the
identity mapping causes an infinite recursive lookup in
undo-equiv-table.
Perhaps the bug is in the Emacs package (Evil in this case) that
doubles up the nils. I ask here because the undo code already seems to
try to account for these to some extent. eg there are a few of these
in the undo function:
(while (eq (car list) nil)
(setq list (cdr list)))
Is this an Emacs bug or an Evil bug?
^ permalink raw reply [flat|nested] 4+ messages in thread
* bug#17236: undo-only hangs when nils double up
2014-04-10 16:15 bug#17236: undo-only hangs when nils double up Barry OReilly
@ 2014-04-10 17:23 ` Andreas Schwab
2014-04-10 20:30 ` Stefan Monnier
1 sibling, 0 replies; 4+ messages in thread
From: Andreas Schwab @ 2014-04-10 17:23 UTC (permalink / raw)
To: Barry OReilly; +Cc: 17236
Barry OReilly <gundaetiapo@gmail.com> writes:
> When there are consecutive nils in buffer-undo-list, undo-only can
> hang.
undo-boundary never creates such an entry.
Andreas.
--
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5
"And now for something completely different."
^ permalink raw reply [flat|nested] 4+ messages in thread
* bug#17236: undo-only hangs when nils double up
2014-04-10 16:15 bug#17236: undo-only hangs when nils double up Barry OReilly
2014-04-10 17:23 ` Andreas Schwab
@ 2014-04-10 20:30 ` Stefan Monnier
2014-04-12 19:24 ` Barry OReilly
1 sibling, 1 reply; 4+ messages in thread
From: Stefan Monnier @ 2014-04-10 20:30 UTC (permalink / raw)
To: Barry OReilly; +Cc: 17236
> Is this an Emacs bug or an Evil bug?
Putting a double nil in the undo-list is an error, so Evil is to blame.
But that doesn't excuse the inf-loop. We should check with `eq' that we
don't add an identity mapping to undo-equiv-table.
Stefan
^ permalink raw reply [flat|nested] 4+ messages in thread
* bug#17236: undo-only hangs when nils double up
2014-04-10 20:30 ` Stefan Monnier
@ 2014-04-12 19:24 ` Barry OReilly
0 siblings, 0 replies; 4+ messages in thread
From: Barry OReilly @ 2014-04-12 19:24 UTC (permalink / raw)
Cc: 17236-done
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Rev 116951. The Evil bug was also reported and fixed.
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^ permalink raw reply [flat|nested] 4+ messages in thread
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2014-04-10 16:15 bug#17236: undo-only hangs when nils double up Barry OReilly
2014-04-10 17:23 ` Andreas Schwab
2014-04-10 20:30 ` Stefan Monnier
2014-04-12 19:24 ` Barry OReilly
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