fix: Fix DidSaveDocument requests blocking the server on startup

crates/ide/src/lib.rs

@@ -486,6 +486,16 @@ pub fn crates_for(&self, file_id: FileId) -> Cancellable<Vec<CrateId>> {
         self.with_db(|db| parent_module::crates_for(db, file_id))
     }
 
+    /// Returns crates this file belongs too.
+    pub fn transitive_rev_deps(&self, crate_id: CrateId) -> Cancellable<Vec<CrateId>> {
+        self.with_db(|db| db.crate_graph().transitive_rev_deps(crate_id).collect())
+    }
+
+    /// Returns crates this file *might* belong too.
+    pub fn relevant_crates_for(&self, file_id: FileId) -> Cancellable<Vec<CrateId>> {
+        self.with_db(|db| db.relevant_crates(file_id).iter().copied().collect())
+    }
+
     /// Returns the edition of the given crate.
     pub fn crate_edition(&self, crate_id: CrateId) -> Cancellable<Edition> {
         self.with_db(|db| db.crate_graph()[crate_id].edition)

crates/ide/src/parent_module.rs

@@ -1,8 +1,9 @@
-use hir::Semantics;
+use hir::{db::DefDatabase, Semantics};
 use ide_db::{
     base_db::{CrateId, FileId, FileLoader, FilePosition},
     RootDatabase,
 };
+use itertools::Itertools;
 use syntax::{
     algo::find_node_at_offset,
     ast::{self, AstNode},
@@ -55,7 +56,12 @@ pub(crate) fn parent_module(db: &RootDatabase, position: FilePosition) -> Vec<Na
 
 /// Returns `Vec` for the same reason as `parent_module`
 pub(crate) fn crates_for(db: &RootDatabase, file_id: FileId) -> Vec<CrateId> {
-    db.relevant_crates(file_id).iter().copied().collect()
+    db.relevant_crates(file_id)
+        .iter()
+        .copied()
+        .filter(|&crate_id| db.crate_def_map(crate_id).modules_for_file(file_id).next().is_some())
+        .sorted()
+        .collect()
 }
 
 #[cfg(test)]

crates/rust-analyzer/src/cargo_target_spec.rs

@@ -118,7 +118,11 @@ pub(crate) fn for_file(
         global_state_snapshot: &GlobalStateSnapshot,
         file_id: FileId,
     ) -> Result<Option<CargoTargetSpec>> {
-        let (cargo_ws, target) = match global_state_snapshot.cargo_target_for_file_id(file_id) {
+        let crate_id = match &*global_state_snapshot.analysis.crates_for(file_id)? {
+            &[crate_id, ..] => crate_id,
+            _ => return Ok(None),
+        };
+        let (cargo_ws, target) = match global_state_snapshot.cargo_target_for_crate_root(crate_id) {
             Some(it) => it,
             None => return Ok(None),
         };

crates/rust-analyzer/src/global_state.rs

@@ -8,7 +8,7 @@
 use crossbeam_channel::{unbounded, Receiver, Sender};
 use flycheck::FlycheckHandle;
 use ide::{Analysis, AnalysisHost, Cancellable, Change, FileId};
-use ide_db::base_db::{FileLoader, SourceDatabase};
+use ide_db::base_db::{CrateId, FileLoader, SourceDatabase};
 use lsp_types::{SemanticTokens, Url};
 use parking_lot::{Mutex, RwLock};
 use proc_macro_api::ProcMacroServer;
@@ -64,7 +64,7 @@ pub(crate) struct GlobalState {
     pub(crate) source_root_config: SourceRootConfig,
     pub(crate) proc_macro_clients: Vec<Result<ProcMacroServer, String>>,
 
-    pub(crate) flycheck: Vec<FlycheckHandle>,
+    pub(crate) flycheck: Arc<[FlycheckHandle]>,
     pub(crate) flycheck_sender: Sender<flycheck::Message>,
     pub(crate) flycheck_receiver: Receiver<flycheck::Message>,
 
@@ -117,6 +117,7 @@ pub(crate) struct GlobalStateSnapshot {
     vfs: Arc<RwLock<(vfs::Vfs, NoHashHashMap<FileId, LineEndings>)>>,
     pub(crate) workspaces: Arc<Vec<ProjectWorkspace>>,
     pub(crate) proc_macros_loaded: bool,
+    pub(crate) flycheck: Arc<[FlycheckHandle]>,
 }
 
 impl std::panic::UnwindSafe for GlobalStateSnapshot {}
@@ -155,7 +156,7 @@ pub(crate) fn new(sender: Sender<lsp_server::Message>, config: Config) -> Global
             source_root_config: SourceRootConfig::default(),
             proc_macro_clients: vec![],
 
-            flycheck: Vec::new(),
+            flycheck: Arc::new([]),
             flycheck_sender,
             flycheck_receiver,
 
@@ -295,6 +296,7 @@ pub(crate) fn snapshot(&self) -> GlobalStateSnapshot {
             mem_docs: self.mem_docs.clone(),
             semantic_tokens_cache: Arc::clone(&self.semantic_tokens_cache),
             proc_macros_loaded: !self.fetch_build_data_queue.last_op_result().0.is_empty(),
+            flycheck: self.flycheck.clone(),
         }
     }
 
@@ -398,10 +400,15 @@ pub(crate) fn anchored_path(&self, path: &AnchoredPathBuf) -> Url {
         url_from_abs_path(path)
     }
 
-    pub(crate) fn cargo_target_for_file_id(
+    pub(crate) fn file_id_to_file_path(&self, file_id: FileId) -> vfs::VfsPath {
+        self.vfs.read().0.file_path(file_id)
+    }
+
+    pub(crate) fn cargo_target_for_crate_root(
         &self,
-        file_id: FileId,
+        crate_id: CrateId,
     ) -> Option<(&CargoWorkspace, Target)> {
+        let file_id = self.analysis.crate_root(crate_id).ok()?;
         let path = self.vfs.read().0.file_path(file_id);
         let path = path.as_path()?;
         self.workspaces.iter().find_map(|ws| match ws {

crates/rust-analyzer/src/handlers.rs

@@ -1782,7 +1782,15 @@ fn run_rustfmt(
 ) -> Result<Option<Vec<lsp_types::TextEdit>>> {
     let file_id = from_proto::file_id(snap, &text_document.uri)?;
     let file = snap.analysis.file_text(file_id)?;
-    let crate_ids = snap.analysis.crates_for(file_id)?;
+
+    // find the edition of the package the file belongs to
+    // (if it belongs to multiple we'll just pick the first one and pray)
+    let edition = snap
+        .analysis
+        .relevant_crates_for(file_id)?
+        .into_iter()
+        .find_map(|crate_id| snap.cargo_target_for_crate_root(crate_id))
+        .map(|(ws, target)| ws[ws[target].package].edition);
 
     let line_index = snap.file_line_index(file_id)?;
 
@@ -1808,9 +1816,7 @@ fn run_rustfmt(
                     );
                 }
             }
-            if let Some(&crate_id) = crate_ids.first() {
+            if let Some(edition) = edition {
-                // Assume all crates are in the same edition
-                let edition = snap.analysis.crate_edition(crate_id)?;
                 cmd.arg("--edition");
                 cmd.arg(edition.to_string());
             }

crates/rust-analyzer/src/main_loop.rs

@@ -10,7 +10,7 @@
 use always_assert::always;
 use crossbeam_channel::{select, Receiver};
 use flycheck::FlycheckHandle;
-use ide_db::base_db::{SourceDatabase, SourceDatabaseExt, VfsPath};
+use ide_db::base_db::{SourceDatabaseExt, VfsPath};
 use itertools::Itertools;
 use lsp_server::{Connection, Notification, Request};
 use lsp_types::notification::Notification as _;
@@ -191,7 +191,7 @@ fn handle_event(&mut self, event: Event) -> Result<()> {
         // NOTE: don't count blocking select! call as a loop-turn time
         let _p = profile::span("GlobalState::handle_event");
 
-        tracing::debug!("handle_event({:?})", event);
+        tracing::debug!("{:?} handle_event({:?})", loop_start, event);
         let task_queue_len = self.task_pool.handle.len();
         if task_queue_len > 0 {
             tracing::info!("task queue len: {}", task_queue_len);
@@ -727,7 +727,7 @@ fn on_notification(&mut self, not: Notification) -> Result<()> {
                         .insert(path.clone(), DocumentData::new(params.text_document.version))
                         .is_err();
                     if already_exists {
-                        tracing::error!("duplicate DidOpenTextDocument: {}", path)
+                        tracing::error!("duplicate DidOpenTextDocument: {}", path);
                     }
                     this.vfs
                         .write()
@@ -774,69 +774,7 @@ fn on_notification(&mut self, not: Notification) -> Result<()> {
                 Ok(())
             })?
             .on::<lsp_types::notification::DidSaveTextDocument>(|this, params| {
-                let mut updated = false;
                 if let Ok(vfs_path) = from_proto::vfs_path(&params.text_document.uri) {
-                    let (vfs, _) = &*this.vfs.read();
-
-                    // Trigger flychecks for all workspaces that depend on the saved file
-                    if let Some(file_id) = vfs.file_id(&vfs_path) {
-                        let analysis = this.analysis_host.analysis();
-                        // Crates containing or depending on the saved file
-                        let crate_ids: Vec<_> = analysis
-                            .crates_for(file_id)?
-                            .into_iter()
-                            .flat_map(|id| {
-                                this.analysis_host
-                                    .raw_database()
-                                    .crate_graph()
-                                    .transitive_rev_deps(id)
-                            })
-                            .sorted()
-                            .unique()
-                            .collect();
-
-                        let crate_root_paths: Vec<_> = crate_ids
-                            .iter()
-                            .filter_map(|&crate_id| {
-                                analysis
-                                    .crate_root(crate_id)
-                                    .map(|file_id| {
-                                        vfs.file_path(file_id).as_path().map(ToOwned::to_owned)
-                                    })
-                                    .transpose()
-                            })
-                            .collect::<ide::Cancellable<_>>()?;
-                        let crate_root_paths: Vec<_> =
-                            crate_root_paths.iter().map(Deref::deref).collect();
-
-                        // Find all workspaces that have at least one target containing the saved file
-                        let workspace_ids =
-                            this.workspaces.iter().enumerate().filter(|(_, ws)| match ws {
-                                project_model::ProjectWorkspace::Cargo { cargo, .. } => {
-                                    cargo.packages().any(|pkg| {
-                                        cargo[pkg].targets.iter().any(|&it| {
-                                            crate_root_paths.contains(&cargo[it].root.as_path())
-                                        })
-                                    })
-                                }
-                                project_model::ProjectWorkspace::Json { project, .. } => project
-                                    .crates()
-                                    .any(|(c, _)| crate_ids.iter().any(|&crate_id| crate_id == c)),
-                                project_model::ProjectWorkspace::DetachedFiles { .. } => false,
-                            });
-
-                        // Find and trigger corresponding flychecks
-                        for flycheck in &this.flycheck {
-                            for (id, _) in workspace_ids.clone() {
-                                if id == flycheck.id() {
-                                    updated = true;
-                                    flycheck.restart();
-                                    continue;
-                                }
-                            }
-                        }
-                    }
-
                     // Re-fetch workspaces if a workspace related file has changed
                     if let Some(abs_path) = vfs_path.as_path() {
                         if reload::should_refresh_for_change(&abs_path, ChangeKind::Modify) {
@@ -844,13 +782,90 @@ fn on_notification(&mut self, not: Notification) -> Result<()> {
                                 .request_op(format!("DidSaveTextDocument {}", abs_path.display()));
                         }
                     }
+
+                    let file_id = this.vfs.read().0.file_id(&vfs_path);
+                    if let Some(file_id) = file_id {
+                        let world = this.snapshot();
+                        let mut updated = false;
+                        let task = move || -> std::result::Result<(), ide::Cancelled> {
+                            // Trigger flychecks for all workspaces that depend on the saved file
+                            // Crates containing or depending on the saved file
+                            let crate_ids: Vec<_> = world
+                                .analysis
+                                .crates_for(file_id)?
+                                .into_iter()
+                                .flat_map(|id| world.analysis.transitive_rev_deps(id))
+                                .flatten()
+                                .sorted()
+                                .unique()
+                                .collect();
+
+                            let crate_root_paths: Vec<_> = crate_ids
+                                .iter()
+                                .filter_map(|&crate_id| {
+                                    world
+                                        .analysis
+                                        .crate_root(crate_id)
+                                        .map(|file_id| {
+                                            world
+                                                .file_id_to_file_path(file_id)
+                                                .as_path()
+                                                .map(ToOwned::to_owned)
+                                        })
+                                        .transpose()
+                                })
+                                .collect::<ide::Cancellable<_>>()?;
+                            let crate_root_paths: Vec<_> =
+                                crate_root_paths.iter().map(Deref::deref).collect();
+
+                            // Find all workspaces that have at least one target containing the saved file
+                            let workspace_ids =
+                                world.workspaces.iter().enumerate().filter(|(_, ws)| match ws {
+                                    project_model::ProjectWorkspace::Cargo { cargo, .. } => {
+                                        cargo.packages().any(|pkg| {
+                                            cargo[pkg].targets.iter().any(|&it| {
+                                                crate_root_paths.contains(&cargo[it].root.as_path())
+                                            })
+                                        })
+                                    }
+                                    project_model::ProjectWorkspace::Json { project, .. } => {
+                                        project.crates().any(|(c, _)| {
+                                            crate_ids.iter().any(|&crate_id| crate_id == c)
+                                        })
+                                    }
+                                    project_model::ProjectWorkspace::DetachedFiles { .. } => false,
+                                });
+
+                            // Find and trigger corresponding flychecks
+                            for flycheck in world.flycheck.iter() {
+                                for (id, _) in workspace_ids.clone() {
+                                    if id == flycheck.id() {
+                                        updated = true;
+                                        flycheck.restart();
+                                        continue;
+                                    }
+                                }
+                            }
+                            // No specific flycheck was triggered, so let's trigger all of them.
+                            if !updated {
+                                for flycheck in world.flycheck.iter() {
+                                    flycheck.restart();
+                                }
+                            }
+                            Ok(())
+                        };
+                        this.task_pool.handle.spawn_with_sender(move |_| {
+                            if let Err(e) = std::panic::catch_unwind(task) {
+                                tracing::error!("DidSaveTextDocument flycheck task panicked: {e:?}")
+                            }
+                        });
+                        return Ok(());
+                    }
                 }
 
                 // No specific flycheck was triggered, so let's trigger all of them.
-                if !updated {
+                for flycheck in this.flycheck.iter() {
-                    for flycheck in &this.flycheck {
+                    flycheck.restart();
-                        flycheck.restart();
-                    }
                 }
                 Ok(())
             })?

crates/rust-analyzer/src/reload.rs

@@ -466,7 +466,7 @@ fn reload_flycheck(&mut self) {
         let config = match self.config.flycheck() {
             Some(it) => it,
             None => {
-                self.flycheck = Vec::new();
+                self.flycheck = Arc::new([]);
                 self.diagnostics.clear_check_all();
                 return;
             }
@@ -510,7 +510,8 @@ fn reload_flycheck(&mut self) {
                     })
                     .collect()
             }
-        };
+        }
+        .into();
     }
 }