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]>

5 files changed, 52 insertions, 25 deletions

diff --git a/crates/ra_lsp_server/src/main.rs b/crates/ra_lsp_server/src/main.rs
index eb4091a3d..82f52a6e8 100644
--- a/crates/ra_lsp_server/src/main.rs
+++ b/crates/ra_lsp_server/src/main.rs
@@ -40,12 +40,23 @@ fn main_inner() -> Result<()> {
     run_server(ra_lsp_server::server_capabilities(), receiver, sender, |params, r, s| {
         let root = params.root_uri.and_then(|it| it.to_file_path().ok()).unwrap_or(cwd);
 
+        let workspace_roots = params
+            .workspace_folders
+            .map(|workspaces| {
+                workspaces
+                    .into_iter()
+                    .filter_map(|it| it.uri.to_file_path().ok())
+                    .collect::<Vec<_>>()
+            })
+            .filter(|workspaces| !workspaces.is_empty())
+            .unwrap_or_else(|| vec![root]);
+
         let opts = params
             .initialization_options
             .and_then(|v| InitializationOptions::deserialize(v).ok())
             .unwrap_or(InitializationOptions::default());
 
-        ra_lsp_server::main_loop(root, opts, r, s)
+        ra_lsp_server::main_loop(workspace_roots, opts, r, s)
     })?;
     log::info!("shutting down IO...");
     threads.join()?;
diff --git a/crates/ra_lsp_server/src/main_loop.rs b/crates/ra_lsp_server/src/main_loop.rs
index 82410bee3..07ac4917a 100644
--- a/crates/ra_lsp_server/src/main_loop.rs
+++ b/crates/ra_lsp_server/src/main_loop.rs
@@ -48,7 +48,7 @@ enum Task {
 const THREADPOOL_SIZE: usize = 8;
 
 pub fn main_loop(
-    ws_root: PathBuf,
+    ws_roots: Vec<PathBuf>,
     options: InitializationOptions,
     msg_receiver: &Receiver<RawMessage>,
     msg_sender: &Sender<RawMessage>,
@@ -59,23 +59,26 @@ pub fn main_loop(
     // FIXME: support dynamic workspace loading.
     let workspaces = {
         let ws_worker = workspace_loader();
-        ws_worker.sender().send(ws_root.clone()).unwrap();
-        match ws_worker.receiver().recv().unwrap() {
-            Ok(ws) => vec![ws],
-            Err(e) => {
-                log::error!("loading workspace failed: {}", e);
-
-                show_message(
-                    req::MessageType::Error,
-                    format!("rust-analyzer failed to load workspace: {}", e),
-                    msg_sender,
-                );
-                Vec::new()
+        let mut loaded_workspaces = Vec::new();
+        for ws_root in &ws_roots {
+            ws_worker.sender().send(ws_root.clone()).unwrap();
+            match ws_worker.receiver().recv().unwrap() {
+                Ok(ws) => loaded_workspaces.push(ws),
+                Err(e) => {
+                    log::error!("loading workspace failed: {}", e);
+
+                    show_message(
+                        req::MessageType::Error,
+                        format!("rust-analyzer failed to load workspace: {}", e),
+                        msg_sender,
+                    );
+                }
             }
         }
+        loaded_workspaces
     };
 
-    let mut state = ServerWorldState::new(ws_root.clone(), workspaces);
+    let mut state = ServerWorldState::new(ws_roots, workspaces);
 
     log::info!("server initialized, serving requests");
 
diff --git a/crates/ra_lsp_server/src/main_loop/handlers.rs b/crates/ra_lsp_server/src/main_loop/handlers.rs
index b96deb061..41d1f759f 100644
--- a/crates/ra_lsp_server/src/main_loop/handlers.rs
+++ b/crates/ra_lsp_server/src/main_loop/handlers.rs
@@ -263,6 +263,7 @@ pub fn handle_runnables(
     let line_index = world.analysis().file_line_index(file_id);
     let offset = params.position.map(|it| it.conv_with(&line_index));
     let mut res = Vec::new();
+    let workspace_root = world.workspace_root_for(file_id);
     for runnable in world.analysis().runnables(file_id)? {
         if let Some(offset) = offset {
             if !runnable.range.contains_inclusive(offset) {
@@ -287,6 +288,7 @@ pub fn handle_runnables(
                 m.insert("RUST_BACKTRACE".to_string(), "short".to_string());
                 m
             },
+            cwd: workspace_root.map(|root| root.to_string_lossy().to_string()),
         };
         res.push(r);
     }
@@ -309,6 +311,7 @@ pub fn handle_runnables(
         bin: "cargo".to_string(),
         args: check_args,
         env: FxHashMap::default(),
+        cwd: workspace_root.map(|root| root.to_string_lossy().to_string()),
     });
     Ok(res)
 }
@@ -627,6 +630,7 @@ pub fn handle_code_lens(
     let line_index = world.analysis().file_line_index(file_id);
 
     let mut lenses: Vec<CodeLens> = Default::default();
+    let workspace_root = world.workspace_root_for(file_id);
 
     // Gather runnables
     for runnable in world.analysis().runnables(file_id)? {
@@ -647,6 +651,7 @@ pub fn handle_code_lens(
                 bin: "cargo".into(),
                 args,
                 env: Default::default(),
+                cwd: workspace_root.map(|root| root.to_string_lossy().to_string()),
             };
 
             let lens = CodeLens {
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)]
diff --git a/crates/ra_lsp_server/src/server_world.rs b/crates/ra_lsp_server/src/server_world.rs
index 4b1d592bb..b2808b817 100644
--- a/crates/ra_lsp_server/src/server_world.rs
+++ b/crates/ra_lsp_server/src/server_world.rs
@@ -1,5 +1,5 @@
 use std::{
-    path::PathBuf,
+    path::{Path, PathBuf},
     sync::Arc,
 };
 
@@ -24,7 +24,7 @@ use crate::{
 #[derive(Debug)]
 pub struct ServerWorldState {
     pub roots_to_scan: usize,
-    pub root: PathBuf,
+    pub roots: Vec<PathBuf>,
     pub workspaces: Arc<Vec<ProjectWorkspace>>,
     pub analysis_host: AnalysisHost,
     pub vfs: Arc<RwLock<Vfs>>,
@@ -37,19 +37,20 @@ pub struct ServerWorld {
 }
 
 impl ServerWorldState {
-    pub fn new(root: PathBuf, workspaces: Vec<ProjectWorkspace>) -> ServerWorldState {
+    pub fn new(folder_roots: Vec<PathBuf>, workspaces: Vec<ProjectWorkspace>) -> ServerWorldState {
         let mut change = AnalysisChange::new();
 
         let mut roots = Vec::new();
-        roots.push(IncludeRustFiles::member(root.clone()));
+        roots.extend(folder_roots.iter().cloned().map(IncludeRustFiles::member));
         for ws in workspaces.iter() {
             roots.extend(IncludeRustFiles::from_roots(ws.to_roots()));
         }
 
-        let (mut vfs, roots) = Vfs::new(roots);
-        let roots_to_scan = roots.len();
-        for r in roots {
-            let is_local = vfs.root2path(r).starts_with(&root);
+        let (mut vfs, vfs_roots) = Vfs::new(roots);
+        let roots_to_scan = vfs_roots.len();
+        for r in vfs_roots {
+            let vfs_root_path = vfs.root2path(r);
+            let is_local = folder_roots.iter().any(|it| vfs_root_path.starts_with(it));
             change.add_root(SourceRootId(r.0.into()), is_local);
         }
 
@@ -68,7 +69,7 @@ impl ServerWorldState {
         analysis_host.apply_change(change);
         ServerWorldState {
             roots_to_scan,
-            root,
+            roots: folder_roots,
             workspaces: Arc::new(workspaces),
             analysis_host,
             vfs: Arc::new(RwLock::new(vfs)),
@@ -90,7 +91,8 @@ impl ServerWorldState {
             match c {
                 VfsChange::AddRoot { root, files } => {
                     let root_path = self.vfs.read().root2path(root);
-                    if root_path.starts_with(&self.root) {
+                    let is_local = self.roots.iter().any(|r| root_path.starts_with(r));
+                    if is_local {
                         self.roots_to_scan -= 1;
                         for (file, path, text) in files {
                             change.add_file(
@@ -193,4 +195,9 @@ impl ServerWorld {
         res.push_str(&self.analysis.status());
         res
     }
+
+    pub fn workspace_root_for(&self, file_id: FileId) -> Option<&Path> {
+        let path = self.vfs.read().file2path(VfsFile(file_id.0.into()));
+        self.workspaces.iter().find_map(|ws| ws.workspace_root_for(&path))
+    }
 }