Deleting multiline text in frames cause crash

I can reproduce, but so far, only with this particular score. Something seems wrong with the text here - I don't always get a crash, but when I do delete lines, the empty lines remain. Anything unusual about how it was created? Were any pre-release builds involved?

I can reproduce from scratch, but I did not yet understood (I hope soon...!) all the ins and outs of this issue. Tricky and weird issue!

The steps:
1) Create new score, or open this file: 7 test scratch.mscz
2) Add an horizontal frame
3) In this frame, add text
4) Leave a gap between the first line of text and the followings. Like this.

5) Now, remove this gap -> Escape
Inexpected result:

6) Return to the previous step ( #4) -> select ABC / ABC / JKL (see attached image below)
If you hit DEL, all the text frame disappears, and if you hit Backspace -> Crash
Sometimes, you receive the reverse result! Do not know why!

Some variations according to the context and the content of the text!

- With this file: 8 test scratch.mscz ,
you need to select the four ABC (after the gap always), sometimes select three ABC is sufficient! -> DEL or Backspace -> you receive a crash (or all text is deleted, or the two in same time!)

- To finish, with this file (different letters), all the steps works fine! 6 test scratch.mscz

Note that a part of this issue (step #5) fails also with a vertical frame,

and "seems" work with frame text. Seems because sometimes not apparently.
Arhhh... once and for all, very unstable! :(

Well, I advance...
For the step #5, the conditions are:
Same letters: in the first text line, in second text line (after the gap), and in the last text line.
See this file to check: new test scratch.mscz
Indeed, you may replace in the third line ( D E F) by an other (A B C): no incidence, in the sense that it fails.
But if you replace the last line (A B C) by (D E F), it works...
For the explanation of the crash, I continue... at least I try!

So, now, I can reproduce constantly the crash.
1) Open this file: 1new test scratch-2.mscz
2) Switch to text edit mode to be at the start of the second text line

3) BackSpace

4) BEFORE escape, select three text lines: 2,3,4 (if you select only two lines, no issue...)

5) Hit DEL or BackSpace

Result: crash, or all text deleted (or the two) : it depends, according to the "mood" of the file for an unknown reason (or due to the instability created by this issue?)

To summarize, it seems that this part (step #5 always) of this issue - see image below - is crucial (but not the only one?) in the occurrence of the crash? This is my understanding for now.

And to finish for today, note again that changing the content of a text line (with the same steps that in the previous comment #5) changes the "game".
As it stands, this remains a mystery to me.
3new test scratch-2.mscz

Great, thanks for the investigation!

An additional element of reflection:

Open this file: 7 test scratch.mscz

At the step # 5 (remove the gap between the first and the second text line -> Escape), you receive this.

So, as you see, the third line, besides the fact that it has not at the expected location, is the same as the second one (and the first also?)
Consequently, following the steps of the comment # 5: crash (or all text deleted) after DEL or BackSpace

- Now, open this file: 7 test scratch bis.mscz
First result: the third line is always in a bad place. But this text line is different from the second (and the first also?)

Result after the same steps in comment #5: it works!

That much is #34526: Special characters and newlines are not pasted correctly in edit mode and may indeed be related - somehow, this all has to do with handling of the newline character I am thinking.

one of the root causes is here https://github.com/musescore/MuseScore/blob/af0e7f13fe9eb5914af3bc69c26…

We potentially delete several lines when we should delete only one because contains() uses == and potentially several lines are empty and so they are equal...

After further investigation (always tricky and consuming time!), it seems that one must distinguish two related issues.

A) First, there is a very former issue that I can always reproduce in the time since a year (and probably before) e.g. with this Nightly: 56177c3, and these steps:

1) New score
2) Insert horizontal frame
3) Add text (the conditions are four similar text lines, with three letters minimum by line), but in contrast with the "second" issue (evocated in a second point below), adding a gap between the first and the second text line is not necessary to create this issue

4) So, select the last three text lines -> BackSpace
Result: correct, in the sense of these lines are deleted, and the first remains.

5) But, if you continue by: Escape -> Undo -> Re-select the same three last lines -> Del
Result: all the text frame is deleted (the four lines) and crash after Undo

Note that if you reverse the scenario at the step #4: Begin to hit Del -> Escape -> Undo -> Re-select -> BackSpace -> Undo -> Crash

B) The "second" issue (remove the gap between the first and second text line -> Escape, with an inexpected result), see also comment #2, occurs very latest. I see a change around February 17-18.


E.g, I receive a correct result with this Nightly on February 16: 91a2d01

After checking, but I am not sure of that at all, this commit might be involved? https://github.com/musescore/MuseScore/commit/db79435ebdfe3d681dc9d2686…
To fix: #47636: Text in Text-Frames not being seen in parts

Fixed in 5f354a9c54

Automatically closed -- issue fixed for 2 weeks with no activity.