Merge #1137

1137: Adds support for multiple editor workspaces on initialization r=matklad a=jrvidal

OK, so this "simple hack" turned out to be way more contrived than I expected :joy:

### What works
This patch only handles multi-folder editor workspaces _on initialization_.
  * I've found that modifying the layout of a workspace in VSCode just reloads the extension, so this hack should be enough for now.
  * Not sure about how emacs-lsp behaves, but we fallback gracefully to the mono-folder workspace, so it should be fine.

### What doesn't work
* [x] `cargo watch` can only watch a single root folder with a `Cargo.toml`. I've left this part untouched but we could either warn that it's not supported or launch _multiple_ `cargo-watch` processes.
* [x] The `rust-analyzer/runnables` command is not functional, since we don't send the correct `cwd`.
* [x] Should we add some happy path test to `heavy_tests`?
* [ ] Going from a single `root` to multiple `roots` leaves us with a couple of `n * m` loops that smell a bit. The number of folders in the editor workspace is probably low though.

Co-authored-by: Roberto Vidal <[email protected]>

1 files changed, 1 insertions, 0 deletions

diff --git a/crates/ra_lsp_server/src/req.rs b/crates/ra_lsp_server/src/req.rs
index e0571fd78..4f35ab9b5 100644
--- a/crates/ra_lsp_server/src/req.rs
+++ b/crates/ra_lsp_server/src/req.rs
@@ -163,6 +163,7 @@ pub struct Runnable {
     pub bin: String,
     pub args: Vec<String>,
     pub env: FxHashMap<String, String>,
+    pub cwd: Option<String>,
 }
 
 #[derive(Serialize, Debug)]