6 files changed, 25 insertions, 3 deletions

diff --git a/crates/project_model/src/lib.rs b/crates/project_model/src/lib.rs
index 8c6cf94c2..c2fde00d5 100644
--- a/crates/project_model/src/lib.rs
+++ b/crates/project_model/src/lib.rs
@@ -50,6 +50,7 @@ pub use proc_macro_api::ProcMacroClient;
 pub enum ProjectManifest {
     ProjectJson(AbsPathBuf),
     CargoToml(AbsPathBuf),
+    DetachedFile(AbsPathBuf),
 }
 
 impl ProjectManifest {
diff --git a/crates/project_model/src/workspace.rs b/crates/project_model/src/workspace.rs
index 607e62ea5..5fd648710 100644
--- a/crates/project_model/src/workspace.rs
+++ b/crates/project_model/src/workspace.rs
@@ -148,6 +148,9 @@ impl ProjectWorkspace {
                 let rustc_cfg = rustc_cfg::get(Some(&cargo_toml), config.target.as_deref());
                 ProjectWorkspace::Cargo { cargo, sysroot, rustc, rustc_cfg }
             }
+            ProjectManifest::DetachedFile(_) => {
+                todo!("TODO kb")
+            }
         };
 
         Ok(res)
diff --git a/crates/rust-analyzer/src/bin/main.rs b/crates/rust-analyzer/src/bin/main.rs
index f0abb5b15..7ee35d52b 100644
--- a/crates/rust-analyzer/src/bin/main.rs
+++ b/crates/rust-analyzer/src/bin/main.rs
@@ -214,7 +214,7 @@ fn run_server() -> Result<()> {
 
             let discovered = ProjectManifest::discover_all(&workspace_roots);
             log::info!("discovered projects: {:?}", discovered);
-            if discovered.is_empty() {
+            if discovered.is_empty() && config.detached_files().is_empty() {
                 log::error!("failed to find any projects in {:?}", workspace_roots);
             }
 
diff --git a/crates/rust-analyzer/src/config.rs b/crates/rust-analyzer/src/config.rs
index b700d025f..570534c9a 100644
--- a/crates/rust-analyzer/src/config.rs
+++ b/crates/rust-analyzer/src/config.rs
@@ -236,6 +236,7 @@ impl Default for ConfigData {
 pub struct Config {
     caps: lsp_types::ClientCapabilities,
     data: ConfigData,
+    detached_files: Vec<ProjectManifest>,
     pub discovered_projects: Option<Vec<ProjectManifest>>,
     pub root_path: AbsPathBuf,
 }
@@ -328,13 +329,24 @@ pub struct WorkspaceSymbolConfig {
 
 impl Config {
     pub fn new(root_path: AbsPathBuf, caps: ClientCapabilities) -> Self {
-        Config { caps, data: ConfigData::default(), discovered_projects: None, root_path }
+        Config {
+            caps,
+            data: ConfigData::default(),
+            detached_files: Vec::new(),
+            discovered_projects: None,
+            root_path,
+        }
     }
-    pub fn update(&mut self, json: serde_json::Value) {
+    pub fn update(&mut self, mut json: serde_json::Value) {
         log::info!("updating config from JSON: {:#}", json);
         if json.is_null() || json.as_object().map_or(false, |it| it.is_empty()) {
             return;
         }
+        self.detached_files = get_field::<Vec<PathBuf>>(&mut json, "detachedFiles", None, "[]")
+            .into_iter()
+            .map(AbsPathBuf::assert)
+            .map(ProjectManifest::DetachedFile)
+            .collect();
         self.data = ConfigData::from_json(json);
     }
 
@@ -387,6 +399,10 @@ impl Config {
         }
     }
 
+    pub fn detached_files(&self) -> &[ProjectManifest] {
+        &self.detached_files
+    }
+
     pub fn did_save_text_document_dynamic_registration(&self) -> bool {
         let caps =
             try_or!(self.caps.text_document.as_ref()?.synchronization.clone()?, Default::default());
diff --git a/crates/rust-analyzer/src/main_loop.rs b/crates/rust-analyzer/src/main_loop.rs
index f837b89dd..cb002f700 100644
--- a/crates/rust-analyzer/src/main_loop.rs
+++ b/crates/rust-analyzer/src/main_loop.rs
@@ -103,6 +103,7 @@ impl fmt::Debug for Event {
 impl GlobalState {
     fn run(mut self, inbox: Receiver<lsp_server::Message>) -> Result<()> {
         if self.config.linked_projects().is_empty()
+            && self.config.detached_files().is_empty()
             && self.config.notifications().cargo_toml_not_found
         {
             self.show_message(
diff --git a/crates/rust-analyzer/src/reload.rs b/crates/rust-analyzer/src/reload.rs
index 0ae2758cc..cfa95275d 100644
--- a/crates/rust-analyzer/src/reload.rs
+++ b/crates/rust-analyzer/src/reload.rs
@@ -146,6 +146,7 @@ impl GlobalState {
         log::info!("will fetch workspaces");
 
         self.task_pool.handle.spawn_with_sender({
+            // TODO kb reload workspace here?
             let linked_projects = self.config.linked_projects();
             let cargo_config = self.config.cargo();