VS Code problem matcher are restricted to be static "regexes". You can't
create a problem matcher dynamically, and you can't use custom code in
lieu of problem matcher.
This creates a problem for rust/cargo compiler errors. They use paths
relative to the root of the Cargo workspace, but VS Code doesn't
necessary know where that root is.
Luckily, there's a way out: our current problem matcher is defined like
this:
"fileLocation": [ "autoDetect", "${workspaceRoot}" ],
That means that relative pahts would be resoleved relative to workspace
root. VS Code allows to specify a command inside `${}`. So we can plug
custom logic there to fetch Cargo's workspace root!
And that's exactly what this PR is doing!
4580: Fix invoking cargo without consulting CARGO env var or standard installation paths r=matklad a=Veetaha
Followup for #4329
The pr essentially fixes [this bug](https://youtu.be/EzQ7YIIo1rY?t=2189)
cc @lefticus
Co-authored-by: veetaha <veetaha2@gmail.com>
This is useful when an extension (e.g. Nix Environment Selector) or launch
configuration sets one or more environment variables.
When `env` is not explicitly specified in the options passed to
`child_process.spawn()` or `vscode.ShellExecution()`, then `process.env` gets
applied automatically. But when an explicit `env` is set, it should inherit from
`process.env` rather than replace it completely.
As per matklad, we now pass the responsibility for finding the binary to the frontend.
Also, added caching for finding the binary path to reduce
the amount of filesystem interactions.
