Clean up generated files before regenerating

Delete all .rs files in target directory before running protobuf codegen to prevent accumulation of files from deleted proto definitions

build/src/main.rs

@@ -47,6 +47,24 @@ fn main() {
     let mut protos = get_protos(&args.protos).collect::<Vec<_>>();
     protos.sort();
 
+    // Clean up old generated files before generating new ones
+    if args.target.exists() {
+        for entry in WalkDir::new(&args.target)
+            .into_iter()
+            .filter_map(|e| e.ok())
+            .filter(|e| e.path().is_file())
+            .filter(|e| e.path().extension().and_then(|s| s.to_str()) == Some("rs"))
+        {
+            std::fs::remove_file(entry.path()).unwrap_or_else(|e| {
+                panic!(
+                    "Failed to remove old generated file {:?}: {}",
+                    entry.path(),
+                    e
+                )
+            });
+        }
+    }
+
     let kinds = get_kinds(&args.protos, &protos);
     let service_generator = ServiceGenerator::new(kinds);
     let service_files = service_generator.files.clone();