fix: Do not panic if rust-analyzer fails to spawn the discover command

crates/rust-analyzer/src/command.rs

@@ -10,6 +10,7 @@ use std::{
     process::{ChildStderr, ChildStdout, Command, Stdio},
 };
 
+use anyhow::Context;
 use crossbeam_channel::Sender;
 use paths::Utf8PathBuf;
 use process_wrap::std::{StdChildWrapper, StdCommandWrap};
@@ -156,7 +157,7 @@ impl<T: Sized + Send + 'static> CommandHandle<T> {
         parser: impl JsonLinesParser<T>,
         sender: Sender<T>,
         out_file: Option<Utf8PathBuf>,
-    ) -> std::io::Result<Self> {
+    ) -> anyhow::Result<Self> {
         command.stdout(Stdio::piped()).stderr(Stdio::piped()).stdin(Stdio::null());
 
         let program = command.get_program().into();
@@ -168,7 +169,10 @@ impl<T: Sized + Send + 'static> CommandHandle<T> {
         child.wrap(process_wrap::std::ProcessSession);
         #[cfg(windows)]
         child.wrap(process_wrap::std::JobObject);
-        let mut child = child.spawn().map(JodGroupChild)?;
+        let mut child = child
+            .spawn()
+            .map(JodGroupChild)
+            .with_context(|| "Failed to spawn command: {child:?}")?;
 
         let stdout = child.0.stdout().take().unwrap();
         let stderr = child.0.stderr().take().unwrap();

crates/rust-analyzer/src/discover.rs

@@ -1,6 +1,6 @@
 //! Infrastructure for lazy project discovery. Currently only support rust-project.json discovery
 //! via a custom discover command.
-use std::{io, path::Path};
+use std::path::Path;
 
 use crossbeam_channel::Sender;
 use ide_db::FxHashMap;
@@ -47,7 +47,7 @@ impl DiscoverCommand {
         &self,
         discover_arg: DiscoverArgument,
         current_dir: &Path,
-    ) -> io::Result<DiscoverHandle> {
+    ) -> anyhow::Result<DiscoverHandle> {
         let command = &self.command[0];
         let args = &self.command[1..];
 

crates/rust-analyzer/src/main_loop.rs

@@ -825,33 +825,29 @@ impl GlobalState {
             }
             Task::DiscoverLinkedProjects(arg) => {
                 if let Some(cfg) = self.config.discover_workspace_config() {
-                    // the clone is unfortunately necessary to avoid a borrowck error when
-                    // `self.report_progress` is called later
-                    let title = &cfg.progress_label.clone();
                     let command = cfg.command.clone();
                     let discover = DiscoverCommand::new(self.discover_sender.clone(), command);
 
-                    if self.discover_jobs_active == 0 {
-                        self.report_progress(title, Progress::Begin, None, None, None);
-                    }
-                    self.discover_jobs_active += 1;
-
                     let arg = match arg {
                         DiscoverProjectParam::Buildfile(it) => DiscoverArgument::Buildfile(it),
                         DiscoverProjectParam::Path(it) => DiscoverArgument::Path(it),
                     };
 
-                    let handle = discover
-                        .spawn(
-                            arg,
-                            &std::env::current_dir()
-                                .expect("Failed to get cwd during project discovery"),
-                        )
-                        .unwrap_or_else(|e| {
-                            panic!("Failed to spawn project discovery command: {e}")
-                        });
-
-                    self.discover_handles.push(handle);
+                    match discover.spawn(arg, self.config.root_path().as_ref()) {
+                        Ok(handle) => {
+                            if self.discover_jobs_active == 0 {
+                                let title = &cfg.progress_label.clone();
+                                self.report_progress(title, Progress::Begin, None, None, None);
+                            }
+                            self.discover_jobs_active += 1;
+                            self.discover_handles.push(handle)
+                        }
+                        Err(e) => self.show_message(
+                            lsp_types::MessageType::ERROR,
+                            format!("Failed to spawn project discovery command: {e:#}"),
+                            false,
+                        ),
+                    }
                 }
             }
             Task::FetchBuildData(progress) => {

crates/rust-analyzer/src/test_runner.rs

@@ -101,7 +101,7 @@ impl CargoTestHandle {
         ws_target_dir: Option<&Utf8Path>,
         test_target: TestTarget,
         sender: Sender<CargoTestMessage>,
-    ) -> std::io::Result<Self> {
+    ) -> anyhow::Result<Self> {
         let mut cmd = toolchain::command(Tool::Cargo.path(), root, &options.extra_env);
         cmd.env("RUSTC_BOOTSTRAP", "1");
         cmd.arg("--color=always");