Syntax highlighting became much slower with 'v0.39.2' and later

[onurusluca]

Related to #1615 also probably to #1600

Creating a more detailed and different issue on @johnsoncodehk request.

After some tests I found that with v0.39.2 Volar got very slow and sluggish.

v0.39.2 and later:

v0.39.1 and before (less than a second):

This problem may be caused by a commit after d27d989 or later . Because all the commits after that are included in v0.39.2.

I am looking into it but it would be better if someone with more experience in Volar took a look at it.

Sharing some details for context:

VsCode: June 2022 (version 1.69)

Operating System:
Microsoft Windows 10 Home 64-bit
CPU:
Intel(R) Core(TM) i7-10875H CPU @ 2.30GHz
Motherboard:
Alienware Alienware m17 R3 (U3E1)
RAM:
32.00 GB Unknown form factor Unknown 2667MHz
GPU:
Intel(R) UHD Graphics 1024 MB
NVIDIA GeForce RTX 2070 Super 4095 MB

System:
OS: Windows 10 10.0.19044
CPU: (16) x64 Intel(R) Core(TM) i7-10875H CPU @ 2.30GHz
Memory: 18.41 GB / 31.77 GB
Binaries:
Node: 18.7.0 - C:\Program Files\nodejs\node.EXE
npm: 8.10.0 - C:\Program Files\nodejs\npm.CMD
Browsers:
Edge: Spartan (44.19041.1266.0), Chromium (103.0.1264.77)
Internet Explorer: 11.0.19041.1566

[johnsoncodehk]

Thank to confirm the commit! GetDocumentVersionRequest is completely used for improve performance, it's removed because it don't have effect on my macbook now, maybe it just affect for windows. I will re-add it.

[onurusluca]

@johnsoncodehk Thanks for the quick reply. To be clear I don't know if GetDocumentVersionRequest causes the problem. It may be that commit or later.

I am more than happy to help testing anything.

[johnsoncodehk]

I found that d27d989 is released with v0.39.1, so it should not the reason.

I think 8673fa1 the most possible lead to this problem, please let me know if volar-0.39.5-alpha.2.vsix.zip can resolve the problem or not, this version try to revert that commit.

[onurusluca]

@johnsoncodehk Hey! Thanks for the reply. I tried this version and it works fine. Not slow, just good, No problems afaic.
Took a look at 8673fa1 . I think diagnostics take some time so slows down the syntax highlighting.

[BryceBarbara]

I'm able to see a performance impact between v0.39.1 and v0.39.2 as well.

v0.39.1	v0.39.2

[BryceBarbara]

Looks like v0.39.5-alpha.2 is also faster for me. I've recorded a gif of it just for sake of completeness:

[johnsoncodehk]

Thanks for the information, I'm not sure if 18b62d1 fixed this problem or not because I can't reproduce this problem on mac, please try v0.39.5 and let me know, thank you.