Memory leak and other issues when saving settings

[mimvdb]

Windows Terminal version (or Windows build number)

1.8.1521.0 (also observed on source build 2021-07-11)

Other Software

No response

Steps to reproduce

Open the settings dialog and spam click save. No option needs to be changed.

Video: 13 seconds in, the settings could not be reloaded from file (not sure if it is not loading or file corruption).
https://user-images.githubusercontent.com/2277504/125179830-a31f3a00-e1f2-11eb-8b6f-6f6aa07896c5.mp4

Expected Behavior

Memory stays roughly the same, settings file can be loaded after saving, main UI does not extend past its borders.

Actual Behavior

Memory grows and is not reclaimed, settings file can sometimes not be loaded after saving, UI grows past its borders during reloading.

(Second and third only discovered after deciding to record a video for the memory leak)

Not sure if you want separate tracking issues for these, let me know.

[zadjii-msft]

Not sure if you want separate tracking issues for these, let me know.

Typically, yea, we'd prefer separate issues, but since you've already got #10619 open for the overflow bit, we can just leave this open for the memory leak. I've got a strong suspicion that the memory leak and the "failed to load settings" dialog will end up with the same root cause ☺️

[mimvdb]

Unfortunately the question here seems to be what doesn't leak.

• The settings.Copy() doesn't seem to leak 😄
• Determining selectedItemTag

Besides that pretty much any interaction the MainPage::UpdateSettings has with the UI causes the growing memory as seen in the video. Some particulars:

• Any call to _Navigate seems to leak, setting the CacheSize of the contentFrame to 0 doesn't help
• Calls that manipulate the menuItems such as menuItems.ReplaceAll or Clear/Append leak even when the same elements are used
• Calling ReplaceAll twice or Clear/Appending multiple times back to back causes a crash for some reason

I'm stopping my investigation here. Perhaps it is easier to debug with access to the Windows.UI.* source if the terminal team has access?