Memory leak upon opening MusicXML file exported from Sibelius #23276
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I should mention that I asked the collaborator to send me the individual parts that he'd tweaked instead of the whole score, and those opened fine. I noticed they'd been exported as .musicxml rather than .mxl files, which I guess might contribute. They're inside the ZIP attached below :) |
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The score from musescore#23276 contains a weird situation: notes in voice 2, while there is a measure repeat sign in voice 1. And that repeated for the entire score. The playback model would render a measure repeat in two situations: 1) when finding one 2) when a segment's measure turns out to be a measure repeat measure. "Rendering" means here that it looks back at the previous measure and renders that to the location of the measure repeat. So, for measure 2 of that score from that issue, it would first encounter the measure repeat element and render playback for it, and thus for the voice 2 notes, it would notice that their measure is a measure repeat measure and thus render the measure repeat _again_. So, we re-look at measure 1 twice. For measure 2, that was just a bit wasteful, but on the other hand not catastrophic. Where it gets exciting is _beyond_ measure 2. Measure 3 contains the same situation as measure 2. So, for measure 3, we look back at measure 2 twice. But for each time that we look at measure 2, we look twice at measure 1. So, now we look 4 times at measure 1! And it only gets worse from here; _exponentially_ worse, to be precise. We solve this by only checking whether the current measure is a measure repeat once per staff, i.e. at the first voice. This way, we're back in the linear world. (Well, rendering the n-th measure now takes linear time, so rendering n measures takes quadratic time.)
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It turned out that this was not a memory leak, and not even a real infinite loop, but a very bad case of exponential recursion. Fortunately, the solution was not too complicated. |
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Issue type
Import/export issue
Bug description
I'm currently collaborating on a score with a Sibelius user. He has sent me a MusicXML file with some changes, and when I open it MuseScore hangs and starts eating memory. The file is only 44KB, and it opens correctly in Soundslice, so I don't think it's corrupted.
I haven't had to import a MusicXML file since I switched to MS4, so I don't know if this is a new problem or if it's been present since the update. I also don't have MS3 installed on my current computer, so I'd rather not check if it opens in that. I do know that it happened both on the previous version I had installed (4.3.1, I believe) and the latest version (4.3.2), as I tried upgrading to see if it would resolve the problem. I definitely have opened MusicXML files from the same collaborator on MuseScore 3 without trouble, but as mentioned I haven't tested this specific file in MS3.
My system is running Windows 11 23H2, a Ryzen 7 7840HS, 32GB DDR5-5600 and a 500GB WD SN740. Let me know if you need anything more from me.
Thanks in advance for your help, and even bigger thanks for the awesome software! :)
Steps to reproduce
*compressed to ZIP as GitHub won't allow me to upload .mxl files
Screenshots/Screen recordings
In the below screenshot:
MuseScore Version
4.3.1, 4.3.2
Regression
I don't know
Operating system
Windows 11 23H2 (build 22631.3737)
Additional context
No response
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