Outline view only filled after typing

[mrx23dot]

Issue Type: Bug

Outline view works before installing Pylance.
I install Pylance
python.languageServer is set from Jedi to Pylance
Then Outline view is only populated when I start typing.

My guess is that the parsing engine is not started till I start typing.

Extension version: 2021.9.1
VS Code version: Code 1.60.1 (83bd43bc519d15e50c4272c6cf5c1479df196a4d, 2021-09-10T17:07:10.714Z)
OS version: Windows_NT x64 10.0.18363
Restricted Mode: No

System Info

Item	Value
CPUs	Intel(R) Core(TM) i7-10510U CPU @ 1.80GHz (8 x 2304)
GPU Status	2d_canvas: enabled gpu_compositing: enabled multiple_raster_threads: enabled_on oop_rasterization: enabled opengl: enabled_on rasterization: enabled skia_renderer: enabled_on video_decode: enabled vulkan: disabled_off webgl: enabled webgl2: enabled
Load (avg)	undefined
Memory (System)	15.81GB (4.09GB free)
Process Argv	--crash-reporter-id e4b48720-5a3d-4415-bc92-03f829fdb834
Screen Reader	no
VM	0%

A/B Experiments

vsliv368:30146709
vsreu685:30147344
python383:30185418
vspyt653:30270858
pythonvspyt602:30300191
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pythonptprofiler:30281270
vshan820:30294714
vstes263:30335439
vscoreces:30358480
pythondataviewer:30285071
pythonvsuse255:30340121
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pythonvspyt200:30340761
vscextlangct:30333562
binariesv615:30325510
vsccppwt:30364497
pythonvssor306:30344512
bridge0708:30335490
pygetstartedc2:30360494
bridge0723:30353136
pythonrunftest32:30365366
pythonf5test824:30361777
javagetstartedt:30364666
pythonvspyt187:30365361
pydsgst2:30361792
vscus224cf:30367820
vssid140cf:30363604
vssur157:30367808

[erictraut]

This is related to #1424.

I suspect it's due to an interaction between the Python extension and Pylance. If the initial outline request arrives before the Python extension is fully initialized, the request is not forwarded to Pylance. That's just a theory based on the symptoms.

[jakebailey]

How annoying; I really thought this race had long since been fixed.

Overall, this whole thing is confusing. What makes the outline different than something like semantic tokens, which is also sent when a file is opened or the LS starts?

@mrx23dot If you can reproduce this easily, would you mind gathering an LSP trace doing the steps you described?

You can enable LSP tracing by setting the (undocumented) setting "python.trace.server": "verbose", reloading, then copy the output from the Python Language Server output window.

[mrx23dot]

Sure, before line 4660 is the startup, then I start typing.

lang_serv_log.txt

It's reproducible with a clean install, without any settings. Everything should be latest version.

[erictraut]

The outline information comes from the LSP request 'textDocument/documentSymbol'. You can see this was requested at line 6872 and was returned at line 6880 in the log. It is not requested prior to that. This request should have been received just after the document was opened (line 722).

[jakebailey]

Thanks for the logs; I can definitely see that there's no documentSymbol before the first didChange. This to me smells like a client bug; surely VS Code should be sending the request after it opens the document. We don't even get one. (And we are also very happy to handle documentSymbol on unopened documents too; it's just that VS Code didn't even send the request...)

[erictraut]

When I investigated this earlier, I was never able to get this to repro with pyright, but I was able to repro it with pylance + the Python extension. So I suspect it's a race condition somewhere. My guess is that it's in the Python extension, but it's possible that it's in VS Code itself, and the longer startup time of the Python extension triggers the race condition.

[mrx23dot]

If we are sure that pylance displays every signal from VS without filtering that would mean VS didn't emit the signal.

[heejaechang]

@mrx23dot I can't repro this with the latest pylance. please reopen if it still repro.