Intelisense mulfunctions when RxCpp is used

[dzmitry-babrovich]

Issue Type: Bug

I have create repository at https://github.com/dzmitry-babrovich/rxcpp-intelisense-bug to reproduce the bug.
The container installs RxCpp and part of docker image generation. Check README.md for instructions how to reproduce intelisense mulfunctioning when RxCpp is used.

Extension version: 0.28.2
VS Code version: Code 1.45.1 (5763d909d5f12fe19f215cbfdd29a91c0fa9208a, 2020-05-14T08:27:22.494Z)
OS version: Linux x64 5.3.0-28-generic
Remote OS version: Linux x64 5.3.0-28-generic

System Info

Item	Value
CPUs	Intel(R) Core(TM) i7-10510U CPU @ 1.80GHz (8 x 3400)
GPU Status	2d_canvas: enabled flash_3d: enabled flash_stage3d: enabled flash_stage3d_baseline: enabled gpu_compositing: enabled multiple_raster_threads: enabled_on oop_rasterization: disabled_off protected_video_decode: unavailable_off rasterization: disabled_software skia_renderer: disabled_off_ok video_decode: unavailable_off viz_display_compositor: enabled_on viz_hit_test_surface_layer: disabled_off_ok webgl: enabled webgl2: enabled
Load (avg)	1, 0, 0
Memory (System)	15.43GB (7.79GB free)
Process Argv	--no-sandbox --unity-launch
Screen Reader	no
VM	0%
DESKTOP_SESSION	plasma
XDG_CURRENT_DESKTOP	KDE
XDG_SESSION_DESKTOP	KDE
XDG_SESSION_TYPE	x11

Item	Value
Remote	Dev Container: C++ Sample
OS	Linux x64 5.3.0-28-generic
CPUs	Intel(R) Core(TM) i7-10510U CPU @ 1.80GHz (8 x 3400)
Memory (System)	15.43GB (7.79GB free)
VM	0%

[michelleangela]

@dzmitry-babrovich
I tried the provided repro and was able to reproduce the issue when including any files from the /usr/local/include/rxcpp path and if the C++ standard version is C++14 or gnu++14 or less. Since the default C++ standard of the gcc-8 compiler that's installed on the docker image is gnu++14, this is what the extension uses as default.

I found that by setting the C++ standard to c++17 or gnu++17, then IntelliSense works again with the included RxCpp file. Is this the same case for your project or does the issue persist even when the C++ standard version is set correctly? Does RxCpp library depend on a specific C++ standard version?

[dzmitry-babrovich]

Hi @michelleangela,
I use RxCPP with C++14 because that's what our company uses. As far as I know RxCpp supports C++11 and above. Mind you compilation time is not great. Where does intelisense take it's compiler setting: from CMakeLists.txt or .vscode/c_cpp_properties.json - option cppStandard?

[michelleangela]

The C/C++ extension gets IntelliSense configuration from c_cpp_properties.json. Information from CMakeLists.txt can be passed on to the extension as well if the "configurationProvider" property is set (see https://code.visualstudio.com/docs/cpp/c-cpp-properties-schema-reference for more info about "configurationProvider ") to a CMake VSCode extension that extracts info from CMakeLists and provides it to the C/C++ extension. The C/C++ extension can also get IntelliSense configuration info from a compile_commands.json file, by setting the "compileCommands" property in c_cpp_properties.json to the path of a compile_commands.json. Only set either "configurationProvider" or "compileCommands", but not both. If neither of those two properties are set, then IntelliSense will get info from the set properties in c_cpp_properties.json (or default values if no c_cpp_properties.json is customized).

You can run C/C++: Log Diagnostics from the VS Code command palette to see the actual IntelliSense configurations that are used.

[dzmitry-babrovich]

Hi - I have added c_cpp_properties.json to the repo and pushed it up. Unfortunatelly I am still observing the same issue. Here what I get in log diagnostic:

-------- Diagnostics - 6/10/2020, 8:24:56 PM
Version: 0.28.3
Current Configuration:
{
"name": "Linux",
"defines": [],
"compilerPath": "/usr/bin/gcc",
"cStandard": "c18",
"cppStandard": "c++17",
"intelliSenseMode": "gcc-x64",
"includePath": [
"/usr/local/include"
],
"compilerArgs": [],
"browse": {
"path": [
"/usr/local/include",
"${workspaceFolder}"
],
"limitSymbolsToIncludedHeaders": true
}
}
Translation Unit Mappings:
[ /workspaces/rxcpp-intelisense-bug/main.cpp ]:
/workspaces/rxcpp-intelisense-bug/main.cpp
Translation Unit Configurations:
[ /workspaces/rxcpp-intelisense-bug/main.cpp ]:
Process ID: 429
Memory Usage: 0 MB
Compiler Path: /usr/bin/gcc
Includes:
/usr/include/c++/8
/usr/include/x86_64-linux-gnu/c++/8
/usr/include/c++/8/backward
/usr/lib/gcc/x86_64-linux-gnu/8/include
/usr/local/include
/usr/lib/gcc/x86_64-linux-gnu/8/include-fixed
/usr/include/x86_64-linux-gnu
/usr/include
Standard Version: c++17
IntelliSense Mode: gcc-x64
Other Flags:
--g++
--gnu_version=80300
Total Memory Usage: 0 MB

[michelleangela]

It looks like the issue may have something to do with the IntelliSense process (cpptools-srv) being slow to start, may be about 5-6 secs. Note that there will be an IntelliSense (cpptools-srv) per translation unit, but there should only be one extension process (cpptools). The extension process will spawn a cpptool-srv process per translation unit. If the log from C/C++: Log Diagnostics show that memory usage is 0 MB or says "no active translation units", it means the cpptools-srv is not running.

Regardless of the C++ standard version, IntelliSense was able to work provided that the cpptools-srv was able to start running. I haven't figure out yet what's causing the IntelliSense process to not start either immediately or not start at all, perhaps this has something to do with the container.

FYI: I didn't see the uploaded c_cpp_proeprties.json in https://github.com/dzmitry-babrovich/rxcpp-intelisense-bug/tree/master/.vscode, but this may not be a configuration issue, but I can just manually create a local copy of c_cpp_proeprties.json if needed.

[michelleangela]

This has been determined to be an issue with the IntelliSense engine that is shared with Visual Studio.

Edit:
A fix is in progress.

[sean-mcmanus]

This should be fixed with https://github.com/microsoft/vscode-cpptools/releases/tag/0.29.0-insiders .