Extension API to open file in read-only mode

[Rexios80]

When working on Dart/Flutter projects, it is very easy to accidentally edit files in the pub cache when viewing the source files of dependencies. This corrupts the source, which leads to corrupted builds. We would like the ability for the Dart extension to mark these files as read-only.

See Dart-Code/Dart-Code#5993

[DanTup]

This also applies to other languages, for example node_modules, including the ones inside VS Code's own installation... I just ctrl+clicked through to C:\Users\danny\AppData\Local\Programs\Microsoft VS Code\cfbea10c5f\resources\app\extensions\node_modules\typescript\lib\lib.es5.d.ts and it'll happily let me modify the file without any complaints 🙃

[DanTup]

I just discovered files.readonlyInclude which might be the answer here. We should be able to contribute some configurationDefaults for this from Dart, and perhaps VS Code should include its own installation folders as defaults?

[vs-code-engineering]

This feature request is now a candidate for our backlog. The community has 60 days to upvote the issue. If it receives 20 upvotes we will move it to our backlog. If not, we will close it. To learn more about how we handle feature requests, please see our documentation.

Happy Coding!