assembly: check library has at least one export

assembly/src/library/mod.rs

@@ -72,12 +72,16 @@ impl Library {
     /// Constructs a new [`Library`] from the provided MAST forest and a set of exports.
     ///
     /// # Errors
+    /// Returns an error if the set of exports is empty.
     /// Returns an error if any of the specified exports do not have a corresponding procedure root
     /// in the provided MAST forest.
     pub fn new(
         mast_forest: Arc<MastForest>,
         exports: BTreeMap<QualifiedProcedureName, MastNodeId>,
     ) -> Result<Self, LibraryError> {
+        if exports.is_empty() {
+            return Err(LibraryError::NoExport);
+        }
         for (fqn, &proc_body_id) in exports.iter() {
             if !mast_forest.is_procedure_root(proc_body_id) {
                 return Err(LibraryError::NoProcedureRootForExport { procedure_path: fqn.clone() });
@@ -177,6 +181,9 @@ impl Deserializable for Library {
         let mast_forest = Arc::new(MastForest::read_from(source)?);
 
         let num_exports = source.read_usize()?;
+        if num_exports == 0 {
+            return Err(DeserializationError::InvalidValue(String::from("No exported procedures")));
+        };
         let mut exports = BTreeMap::new();
         for _ in 0..num_exports {
             let proc_module = source.read()?;
@@ -353,10 +360,6 @@ impl TryFrom<Library> for KernelLibrary {
     type Error = LibraryError;
 
     fn try_from(library: Library) -> Result<Self, Self::Error> {
-        if library.exports.is_empty() {
-            return Err(LibraryError::NoExport);
-        }
-
         let kernel_path = LibraryPath::from(LibraryNamespace::Kernel);
         let mut proc_digests = Vec::with_capacity(library.exports.len());
 

miden/masm-examples/bundle/lib_noexports/lib.masm

@@ -0,0 +1,3 @@
+proc.lib_proc
+    swap
+end

miden/tests/integration/cli/cli_test.rs

@@ -47,3 +47,12 @@ fn cli_bundle_debug() {
     cmd.arg("bundle").arg("--debug").arg("./masm-examples/bundle/lib");
     cmd.assert().success();
 }
+
+#[test]
+fn cli_bundle_no_exports() {
+    let mut cmd = bin_under_test().command();
+    cmd.arg("bundle").arg("./masm-examples/bundle/lib_noexports");
+    cmd.assert()
+        .failure()
+        .stderr(predicate::str::contains("library must contain at least one exported procedure"));
+}