Lock shared for commands that don't write artifacts

tooling/nargo_cli/src/cli/mod.rs

@@ -135,17 +135,19 @@ pub(crate) fn start_cli() -> eyre::Result<()> {
         config.program_dir = program_dir;
     }
 
-    let lock_file = if needs_lock(&command) {
-        let toml_path = get_package_manifest(&config.program_dir)?;
-        let file = File::open(toml_path).expect("Expected Nargo.toml to exist");
-        if file.try_lock_exclusive().is_err() {
+    let toml_path = get_package_manifest(&config.program_dir)?;
+    let lock_file = File::open(toml_path).expect("Expected Nargo.toml to exist");
+
+    if needs_exclusive_lock(&command) {
+        if lock_file.try_lock_exclusive().is_err() {
             eprintln!("Waiting for lock on Nargo.toml...");
         }
-
-        file.lock_exclusive().expect("Failed to lock Nargo.toml");
-        Some(file)
+        lock_file.lock_exclusive().expect("Failed to lock Nargo.toml");
     } else {
-        None
+        if lock_file.try_lock_shared().is_err() {
+            eprintln!("Waiting for lock on Nargo.toml...");
+        }
+        lock_file.lock_shared().expect("Failed to lock Nargo.toml");
     };
 
     match command {
@@ -164,9 +166,7 @@ pub(crate) fn start_cli() -> eyre::Result<()> {
         NargoCommand::GenerateCompletionScript(args) => generate_completion_script_cmd::run(args),
     }?;
 
-    if let Some(lock_file) = lock_file {
-        lock_file.unlock().expect("Failed to unlock Nargo.toml");
-    }
+    lock_file.unlock().expect("Failed to unlock Nargo.toml");
 
     Ok(())
 }
@@ -215,7 +215,7 @@ fn command_dir(cmd: &NargoCommand, program_dir: &Path) -> Result<Option<PathBuf>
     Ok(Some(nargo_toml::find_root(program_dir, workspace)?))
 }
 
-fn needs_lock(cmd: &NargoCommand) -> bool {
+fn needs_exclusive_lock(cmd: &NargoCommand) -> bool {
     match cmd {
         NargoCommand::Check(..)
         | NargoCommand::Compile(..)