problemmatcher gives inconsistent results

[mischw]

Issue Type: Bug

When running a simple custom problemmatcher it gives inconsistent results. Sometimes showing duplicate problems, sometimes not showing all problems.

I try to attach a video of the issue here:

I reload the window to show this is probably related but different behavior from #132551

recording.mp4

VS Code version: Code 1.60.0 (e7d7e9a, 2021-09-01T10:43:02.136Z)
OS version: Linux x64 5.13.13-1-MANJARO
Restricted Mode: No

System Info

Item	Value
CPUs	Intel(R) Core(TM) i5-5300U CPU @ 2.30GHz (4 x 2900)
GPU Status	2d_canvas: enabled gpu_compositing: enabled multiple_raster_threads: enabled_on oop_rasterization: disabled_off opengl: enabled_on rasterization: disabled_software skia_renderer: enabled_on video_decode: disabled_software vulkan: disabled_off webgl: enabled webgl2: enabled
Load (avg)	1, 2, 1
Memory (System)	7.47GB (0.65GB free)
Process Argv	--enable-features=UseOzonePlatform --ozone-platform=wayland --enable-gpu --unity-launch --crash-reporter-id 107c02ea-e02b-42e7-b8db-9d831efd30c2
Screen Reader	no
VM	0%
DESKTOP_SESSION	undefined
XDG_CURRENT_DESKTOP	sway
XDG_SESSION_DESKTOP	undefined
XDG_SESSION_TYPE	wayland

Extensions: none

[alexr00]

When you give the problem a different owner, then it is expected that the problem will show up again.

Tasks problem matching only accepts one problem per "location", where "location" is the file, line, and position of the problem. Since your sample has all problems occur in the same file on the same line, just one of the problems shows.

Are there any other behaviors shown in the video that I'm missing?

[mischw]

Ok, I wasn't aware that there is only one problem per location allowed.

But why does it then display two problems after changing the owner? (Video 00:35 to 00:45) Shouldn't it still be one problem per "location", since I didn't change the problem locations? Maybe it is one problem per location and owner, and the problem of the old owner is not deleted somehow?
I expected to have it display one problem, or all three of them. Showing two out of three problems seems random. If the "anothermessage" problem is only shown because the problemMatcher now has a different owner, then why does it show the "message" and the "anothermessage" as output? Maybe there is some internal state that did not get reinitialized when the owner changes?

Also, at 01:05 to 01:10 I change the owner once again, and it goes from two problems to three problems. But the last one is actually a duplicate of the second one (2 x "anothermessage"). Even if this is due to the third introduced owner, which I think is confusing in itself, the duplicate does make no sense to me.

[alexr00]

The owner is part of the ID of the problem so each time you run it it with a new owner you'll get a new problem. The old problem is not cleared because a problem matcher with the same owner has not been run again.