Auto merge of #12856 - Veykril:multi-proc-srv, r=Veykril

feat: Spawn a proc-macro-srv instance per workspace

cc https://github.com/rust-lang/rust-analyzer/issues/12855

The idea is to have each server be spawned with the appropriate toolchain, that way workspaces with differing toolchains shouldn't suffer from proc-macro abi mismatches.

crates/rust-analyzer/src/cli/load_cargo.rs

@@ -60,9 +60,9 @@ pub fn load_workspace(
 
     let proc_macro_client = if load_config.with_proc_macro {
         let path = AbsPathBuf::assert(std::env::current_exe()?);
-        Some(ProcMacroServer::spawn(path, &["proc-macro"]).unwrap())
+        Ok(ProcMacroServer::spawn(path, &["proc-macro"]).unwrap())
     } else {
-        None
+        Err("proc macro server not started".to_owned())
     };
 
     let crate_graph = ws.to_crate_graph(
@@ -89,7 +89,7 @@ pub fn load_workspace(
     if load_config.prefill_caches {
         host.analysis().parallel_prime_caches(1, |_| {})?;
     }
-    Ok((host, vfs, proc_macro_client))
+    Ok((host, vfs, proc_macro_client.ok()))
 }
 
 fn load_crate_graph(

crates/rust-analyzer/src/global_state.rs

@@ -61,7 +61,7 @@ pub(crate) struct GlobalState {
     pub(crate) proc_macro_changed: bool,
     pub(crate) last_reported_status: Option<lsp_ext::ServerStatusParams>,
     pub(crate) source_root_config: SourceRootConfig,
-    pub(crate) proc_macro_client: Option<ProcMacroServer>,
+    pub(crate) proc_macro_clients: Vec<Result<ProcMacroServer, String>>,
 
     pub(crate) flycheck: Vec<FlycheckHandle>,
     pub(crate) flycheck_sender: Sender<flycheck::Message>,
@@ -151,7 +151,7 @@ impl GlobalState {
             proc_macro_changed: false,
             last_reported_status: None,
             source_root_config: SourceRootConfig::default(),
-            proc_macro_client: None,
+            proc_macro_clients: vec![],
 
             flycheck: Vec::new(),
             flycheck_sender,

crates/rust-analyzer/src/handlers.rs

@@ -44,7 +44,7 @@ use crate::{
 };
 
 pub(crate) fn handle_workspace_reload(state: &mut GlobalState, _: ()) -> Result<()> {
-    state.proc_macro_client = None;
+    state.proc_macro_clients.clear();
     state.proc_macro_changed = false;
     state.fetch_workspaces_queue.request_op("reload workspace request".to_string());
     state.fetch_build_data_queue.request_op("reload workspace request".to_string());

crates/rust-analyzer/src/reload.rs

@@ -303,18 +303,21 @@ impl GlobalState {
         let files_config = self.config.files();
         let project_folders = ProjectFolders::new(&self.workspaces, &files_config.exclude);
 
-        if self.proc_macro_client.is_none() {
+        if self.proc_macro_clients.is_empty() {
             if let Some((path, args)) = self.config.proc_macro_srv() {
-                match ProcMacroServer::spawn(path.clone(), args) {
-                    Ok(it) => self.proc_macro_client = Some(it),
-                    Err(err) => {
-                        tracing::error!(
-                            "Failed to run proc_macro_srv from path {}, error: {:?}",
-                            path.display(),
-                            err
-                        );
-                    }
-                }
+                self.proc_macro_clients = (0..self.workspaces.len())
+                    .map(|_| {
+                        ProcMacroServer::spawn(path.clone(), args.clone()).map_err(|err| {
+                            let error = format!(
+                                "Failed to run proc_macro_srv from path {}, error: {:?}",
+                                path.display(),
+                                err
+                            );
+                            tracing::error!(error);
+                            error
+                        })
+                    })
+                    .collect();
             }
         }
 
@@ -331,15 +334,7 @@ impl GlobalState {
 
         // Create crate graph from all the workspaces
         let crate_graph = {
-            let proc_macro_client = self.proc_macro_client.as_ref();
             let dummy_replacements = self.config.dummy_replacements();
-            let mut load_proc_macro = move |crate_name: &str, path: &AbsPath| {
-                load_proc_macro(
-                    proc_macro_client,
-                    path,
-                    dummy_replacements.get(crate_name).map(|v| &**v).unwrap_or_default(),
-                )
-            };
 
             let vfs = &mut self.vfs.write().0;
             let loader = &mut self.loader;
@@ -359,7 +354,15 @@ impl GlobalState {
             };
 
             let mut crate_graph = CrateGraph::default();
-            for ws in self.workspaces.iter() {
+            for (idx, ws) in self.workspaces.iter().enumerate() {
+                let proc_macro_client = self.proc_macro_clients[idx].as_ref();
+                let mut load_proc_macro = move |crate_name: &str, path: &AbsPath| {
+                    load_proc_macro(
+                        proc_macro_client,
+                        path,
+                        dummy_replacements.get(crate_name).map(|v| &**v).unwrap_or_default(),
+                    )
+                };
                 crate_graph.extend(ws.to_crate_graph(&mut load_proc_macro, &mut load));
             }
             crate_graph
@@ -536,14 +539,14 @@ impl SourceRootConfig {
 /// Load the proc-macros for the given lib path, replacing all expanders whose names are in `dummy_replace`
 /// with an identity dummy expander.
 pub(crate) fn load_proc_macro(
-    server: Option<&ProcMacroServer>,
+    server: Result<&ProcMacroServer, &String>,
     path: &AbsPath,
     dummy_replace: &[Box<str>],
 ) -> ProcMacroLoadResult {
     let res: Result<Vec<_>, String> = (|| {
         let dylib = MacroDylib::new(path.to_path_buf())
             .map_err(|io| format!("Proc-macro dylib loading failed: {io}"))?;
-        let server = server.ok_or_else(|| format!("Proc-macro server not started"))?;
+        let server = server.map_err(ToOwned::to_owned)?;
         let vec = server.load_dylib(dylib).map_err(|e| format!("{e}"))?;
         if vec.is_empty() {
             return Err("proc macro library returned no proc macros".to_string());