fix: reject empty kernel packages before linking

Author: KitaroMoha563

CHANGELOG.md

@@ -22,6 +22,7 @@
 - Added regression coverage for the exact `max_num_continuations` continuation-stack boundary ([#2995](https://github.com/0xMiden/miden-vm/pull/2995)).
 - Fixed AEAD padding handling so encrypt does not overwrite memory next to the plaintext buffer and decrypt leaves the plaintext output tail untouched ([#3008](https://github.com/0xMiden/miden-vm/pull/3008)).
 - Fixed MAST compaction after debug info is cleared so compiler-generated packages do not grow ([#3044](https://github.com/0xMiden/miden-vm/pull/3044)).
+- Rejected empty kernel packages before linking so malformed dependency metadata returns a structured package error instead of reaching the linker's non-empty-kernel assertion ([#3082](https://github.com/0xMiden/miden-vm/pull/3082)).
 
 #### Changes
 

crates/assembly/src/tests.rs

@@ -4990,6 +4990,43 @@ fn regression_empty_kernel_library_is_rejected() {
     assert_diagnostic_lines!(err, "library must contain at least one exported procedure");
 }
 
+#[test]
+fn regression_empty_kernel_package_is_rejected_without_panicking() {
+    use std::panic::{AssertUnwindSafe, catch_unwind};
+
+    let context = TestContext::default();
+    let source_manager = context.source_manager();
+    let kernel_lib = Assembler::new(source_manager.clone())
+        .assemble_kernel(
+            r#"
+            pub proc foo
+                add
+            end
+            "#,
+        )
+        .expect("kernel assembly should succeed");
+    let mut package = *Package::from_library(
+        PackageId::from("kernel"),
+        "1.0.0".parse().unwrap(),
+        TargetType::Kernel,
+        Arc::new(kernel_lib.as_ref().clone()),
+        [],
+    );
+    package.manifest = PackageManifest::new([]).expect("empty package manifest should be valid");
+
+    let linked = catch_unwind(AssertUnwindSafe(|| {
+        Assembler::new(source_manager)
+            .link_package(Arc::new(package), miden_project::Linkage::Dynamic)
+    }));
+    assert!(linked.is_ok(), "assembler panicked while linking an empty kernel package");
+
+    let error = linked.unwrap().expect_err("empty kernel packages should be rejected");
+    assert_diagnostic_lines!(
+        error,
+        "invalid kernel package: does not export any kernel procedures"
+    );
+}
+
 /// Reproduces issue #3035: a MAST with padded basic blocks grows when debug info is cleared and the
 /// forest is compacted via self-merge.
 #[test]

crates/mast-package/src/package/mod.rs

@@ -145,6 +145,11 @@ impl Package {
                 }
             })
             .collect::<Vec<_>>();
+        if exports.is_empty() {
+            return Err(Report::msg(
+                "invalid kernel package: does not export any kernel procedures",
+            ));
+        }
         Kernel::new(&exports).map_err(|err| Report::msg(format!("invalid kernel package: {err}")))
     }
 
@@ -525,6 +530,23 @@ mod tests {
         build_package(name, TargetType::Kernel, &format!("{name}::boot"), [], Vec::new())
     }
 
+    #[test]
+    fn to_kernel_rejects_empty_kernel_exports() {
+        let mut package = build_package("kernel", TargetType::Kernel, "$kernel::boot", [], vec![]);
+        package.manifest =
+            PackageManifest::new([]).expect("empty package manifest should be valid");
+
+        let error = package
+            .to_kernel()
+            .expect_err("kernel packages without exported procedures should be rejected");
+
+        assert!(
+            error
+                .to_string()
+                .contains("invalid kernel package: does not export any kernel procedures")
+        );
+    }
+
     fn kernel_dependency(package: &Package) -> Dependency {
         Dependency {
             name: package.name.clone(),