Add back constant test

Author: aumetra

packages/vm-derive-impl/Cargo.toml

@@ -11,4 +11,4 @@ blake3 = "1.5.4"
 cargo-manifest = "0.15.2"
 proc-macro2 = "1.0.86"
 quote = "1.0.37"
-syn = { version = "2.0.77", features = ["full"] }
+syn = { version = "2.0.77", features = ["extra-traits", "full"] }

packages/vm-derive-impl/src/hash_function.rs

@@ -1,19 +1,48 @@
+use std::hash::{Hash, Hasher};
+
 use proc_macro2::TokenStream;
 use quote::quote;
 
 use super::{bail, maybe};
 
+struct Blake3Hasher {
+    hasher: blake3::Hasher,
+}
+
+impl Blake3Hasher {
+    fn new() -> Self {
+        Self {
+            hasher: blake3::Hasher::new(),
+        }
+    }
+
+    fn consume(self) -> String {
+        self.hasher.finalize().to_hex().to_string()
+    }
+}
+
+impl Hasher for Blake3Hasher {
+    fn write(&mut self, bytes: &[u8]) {
+        self.hasher.update(bytes);
+    }
+
+    fn finish(&self) -> u64 {
+        unimplemented!();
+    }
+}
+
 pub fn hash_function_impl(attr: TokenStream, input: TokenStream) -> TokenStream {
     if !attr.is_empty() {
         bail!(attr, "Unexpected parameters");
     }
 
     // Just verify that this is actually a function
-    let _: syn::ItemFn = maybe!(syn::parse2(input.clone()));
+    let function: syn::ItemFn = maybe!(syn::parse2(input.clone()));
+
+    let mut hasher = Blake3Hasher::new();
+    function.hash(&mut hasher);
 
-    let display = input.to_string();
-    let hex_hash = blake3::hash(display.as_bytes()).to_hex();
-    let hex_hash = hex_hash.as_str();
+    let hex_hash = hasher.consume();
 
     quote! {
         #input

packages/vm/src/modules/file_system_cache.rs

@@ -465,4 +465,13 @@ mod tests {
         assert_eq!(v2, v3);
         assert_eq!(v3, v4);
     }
+
+    #[test]
+    fn module_version_static() {
+        let version = raw_module_version_discriminator();
+        assert_eq!(
+            version,
+            "9ef3de8cb5fb770171ae3ea14db67fe25d946fef383472a18ddd75ced7bfcd4b"
+        );
+    }
 }