fix: transformation of unconstrained contract library methods

noir-projects/aztec-nr/aztec/src/macros/functions/utils.nr

@@ -271,7 +271,45 @@ pub(crate) comptime fn transform_public(f: FunctionDefinition) -> Quoted {
     fn_abi
 }
 
-pub(crate) comptime fn transform_unconstrained(f: FunctionDefinition) {
+pub(crate) comptime fn find_and_transform_top_level_unconstrained_fns(m: Module) {
+    // Top-level unconstrained fns are contract entrypoints, but they're not explicitly designated in any way. They're
+    // the fallback case for a function that matches no other rules.
+    // TODO(#12743): improve this
+
+    // We first find non-standard contract entrypoints, i.e. functions in the `contract` mod that are not private or
+    // public, but which *are* contract entrypoints (i.e. they're not opting out via the #[test] or
+    // #[contract_library_method] attributes). Ideally entrypoints would be explicitly designated instead.
+    let non_private_public_entrypoint_functions = m.functions().filter(|f: FunctionDefinition| {
+        !f.has_named_attribute("private")
+            & !f.has_named_attribute("public")
+            & !f.has_named_attribute("contract_library_method")
+            & !f.has_named_attribute("test")
+    });
+
+    // TODO: uncomment the code below and emit a warning once support for them is added to Noir (tracked in
+    // https://github.com/noir-lang/noir/issues/7714). We can't simply print a message since that'd otherwise break the
+    // output of utils such as `nargo test --list-tests`.
+    // // We don't expect to see any custom constrained entrypoints (i.e. private functions created outside of aztec-nr's
+    // // #[private] macro, possibly resulting in a non-standard interface).
+    // for f in non_private_public_entrypoint_functions.filter(|f: FunctionDefinition| {
+    //     !f.is_unconstrained()
+    // }) {
+    //     let name = f.name();
+    //     warn(
+    //         f"found private contract function '{name}' which does not have the #[private] attribute - make sure you know what you're doing!",
+    //     );
+    // }
+
+    // An unconstrained contract entrypoints is what we call a top-level unconstrained function, to which we apply the
+    // appropriate transformation. Ideally these would be explicitly designated as such instead.
+    for f in non_private_public_entrypoint_functions.filter(|f: FunctionDefinition| {
+        f.is_unconstrained()
+    }) {
+        transform_top_level_unconstrained(f);
+    }
+}
+
+pub(crate) comptime fn transform_top_level_unconstrained(f: FunctionDefinition) {
     let context_creation = quote { let mut context = dep::aztec::context::unconstrained_context::UnconstrainedContext::new(); };
     let module_has_storage = module_has_storage(f.module());
 

noir-projects/aztec-nr/aztec/src/macros/mod.nr

@@ -5,7 +5,10 @@ pub mod notes;
 pub mod storage;
 pub mod events;
 
-use functions::{stub_registry, utils::{create_note_discovery_call, transform_unconstrained}};
+use functions::{
+    stub_registry,
+    utils::{create_note_discovery_call, find_and_transform_top_level_unconstrained_fns},
+};
 use notes::{generate_note_export, NOTES};
 use storage::STORAGE_LAYOUT_NAME;
 
@@ -19,12 +22,8 @@ use crate::discovery::MAX_NOTE_PACKED_LEN;
 /// Note: This is a module annotation, so the returned quote gets injected inside the module (contract) itself.
 pub comptime fn aztec(m: Module) -> Quoted {
     let interface = generate_contract_interface(m);
-    let unconstrained_functions = m.functions().filter(|f: FunctionDefinition| {
-        f.is_unconstrained() & !f.has_named_attribute("test") & !f.has_named_attribute("public")
-    });
-    for f in unconstrained_functions {
-        transform_unconstrained(f);
-    }
+
+    find_and_transform_top_level_unconstrained_fns(m);
 
     let contract_library_method_compute_note_hash_and_nullifier =
         generate_contract_library_method_compute_note_hash_and_nullifier();

noir-projects/noir-contracts/contracts/avm_test_contract/src/main.nr

@@ -103,7 +103,13 @@ pub contract AvmTest {
 
     #[public]
     fn add_args_return(arg_a: Field, arg_b: Field) -> Field {
-        arg_a + arg_b
+        add(arg_a, arg_b)
+    }
+
+    // Auxiliary method to test usage of contract library methods in public fns
+    #[contract_library_method]
+    unconstrained fn add(lhs: Field, rhs: Field) -> Field {
+        lhs + rhs
     }
 
     /************************************************************************
@@ -210,10 +216,13 @@ pub contract AvmTest {
     }
 
     // Helper functions to demonstrate an internal call stack in error messages
+    #[contract_library_method]
     fn inner_helper_with_failed_assertion() {
         let not_true = false;
         assert(not_true == true, "This assertion should fail!");
     }
+
+    #[contract_library_method]
     fn helper_with_failed_assertion() {
         inner_helper_with_failed_assertion();
     }