Incorrect character highlighting in de-bruijn about avy

[abo-abo]

Sometimes, it'll highlight it all correctly, and sometimes, it'll highlight it all wrong. This is an example where part of the highlighting is wrong.

Closing as not reproducible. If you manage to reliably reproduce it, please reopen.

[PythonNut]

@tsdh You've reproduced this, right?

[tsdh]

@PythonNut @abo-abo Yes, I can with the current avy version and emacs -Q. See the two screenshots which also contain the recipe.

As you can see, the overlays in the ;; preceding the lisp comment at the top of the buffer are correct, i.e., every matching char is shown in blue. This should also happen to the long semicolon sequences below but there blue and red alternate.

In contrast to @PythonNut, this is completely reproducible and deterministic here. Or wait, it depends on length of, well, I don't really know. All I can say is that THIS is displayed correctly

;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;;;;;;;;;;;;;;;

while THIS isn't

;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;;;;;;;;;;;;;;;;

The difference is just that the latter has one semicolon more in the last line...

[abo-abo]

See the two screenshots which also contain the recipe.

I'd prefer not to copy sensitive text from the screenshot. Could you just paste the whole text here?

[tsdh]

Yes, of course. Consider this test file avy-bug.el.

;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;

Then start emacs like so: emacs -Q -l ~/path/to/avy/avy.el --eval "(setq avy-style 'de-bruijn)" ~/avy-bug.el and do M-x avy-goto-char RET ; and you'll get the wrong highlighting.

As soon as you delete one single ; (no matter in which line) and try to jump to ; again, the highlighting is correct.

Oh, it's actually the same when you put the contents all on the same line, or break it into 10 or 20 lines, or add spaces in between, etc.. So with the avy defaults, at most 81 consecutive (with only arbitrary whitespace in between) matches work, with 82 and up it doesn't anymore.

Hm, what's 81 for a magic number? Well, by default avy-keys has the length 9, and 9^2 is 81...

[abo-abo]

Can you check again? I think this could be fixed.

[tsdh]

No, I'm sorry, it's still wrong in the same way as explained in my last comment: 81 consecutive matching chars => everything's ok, 82 consecutive matching chars => wrong highlighting.

[abo-abo]

The bug was caused by the assumption that overlays-in is sorted (which it was randomly). Please check if it's fixed now.

[tsdh]

Yes, it is fixed. Thanks a lot!