Expose "effective" SourceFileConfiguration to other extensions

[henryju]

Hi,

Context: I am a developer of the SonarLint static code analyzer. We (SonarSource) have a C/C++ analyzer, and this is one of the most voted feature request by our users to add support of analyzing C/C++ code in VSCode:
https://community.sonarsource.com/t/sonarlint-for-vscode-c-c-support/4732/9
https://community.sonarsource.com/t/sonarlint-vscode-cfamily-support/14566/4

In order to analyze C/C++ source files, our analyzer needs to know compilation settings (compiler, flags, includes, ...). I started to study your extension, and discovered c_cpp_properties.json configuration file, as well as the ability for third party extensions to contribute configuration directly using the extension API:
https://github.com/microsoft/vscode-cpptools-api/blob/master/api.ts#L137

I found very similar requests (#1524, #3978) that were closed after the active configuration was exposed, and suggesting to rely on c_cpp_properties.json. But to me this is not a good solution as configuration may also come from the provider api.

I wonder if you would be open to create a new API, not to contribute SourceFileConfiguration, but for a third party extension to read the effective SourceFileConfiguration (the one you will use on the language server side, after resolving all contributions, and maybe after resolving default compiler includes).

FYI we already did a similar collaboration with the Java team from Microsoft, to enable Java code analysis :)
SonarSource/sonarlint-vscode#28 (comment)

[bobbrow]

I think we could do this without a modification to the API. I would rather expose this information as a Command.

[henryju]

Thanks for considering this.
As a personal choice, I would prefer to rely on a clean API, documented, possibly versioned. I feel using commands to exchange data between extensions is a bit 'hacky'.
But in the end this doesn't make a big difference for us, so it's up to you :)
If you could provide a custom/experimental build of vscode-cpptools with this API/command, I would be more than happy to try it and give feedback.

[J-u-n-o]

Personally I can live if I have to enter the values using a project setting/configuration. Or rely on the "C/C++ IntelliSense, debugging, and code browsing." extension. It also analyses the source files for coloring and jumping to definitions.
But probably this is already considered.

[github-actions]

This feature request has received enough votes to be added to our backlog.