From 8932c515c9b5173ecc045164b970ae03bb4b50c8 Mon Sep 17 00:00:00 2001
From: Aleksandr Kirsanov <unserialize.alias@gmail.com>
Date: Tue, 21 May 2024 17:50:06 +0300
Subject: [PATCH] [FunC] Produce an error on get methods hash (method_id)
 collision

---
 .../func/auto-tests/tests/invalid-get-method-2.fc | 15 +++++++++++++++
 crypto/func/builtins.cpp                          |  2 +-
 crypto/func/func.h                                |  2 +-
 crypto/func/parse-func.cpp                        |  6 ++++++
 4 files changed, 23 insertions(+), 2 deletions(-)
 create mode 100644 crypto/func/auto-tests/tests/invalid-get-method-2.fc

diff --git a/crypto/func/auto-tests/tests/invalid-get-method-2.fc b/crypto/func/auto-tests/tests/invalid-get-method-2.fc
new file mode 100644
index 00000000..e2a8556b
--- /dev/null
+++ b/crypto/func/auto-tests/tests/invalid-get-method-2.fc
@@ -0,0 +1,15 @@
+get int secret() pure {
+    return 0;
+}
+get int balanced() pure {
+    return 1;
+}
+
+int main() {
+    return secret() + balanced();
+}
+
+{-
+@compilation_should_fail
+@stderr GET methods hash collision: `secret` and `balanced` produce the same hash
+-}
diff --git a/crypto/func/builtins.cpp b/crypto/func/builtins.cpp
index aafa9bef..218e173d 100644
--- a/crypto/func/builtins.cpp
+++ b/crypto/func/builtins.cpp
@@ -28,7 +28,7 @@ using namespace std::literals::string_literals;
  */
 
 int glob_func_cnt, undef_func_cnt, glob_var_cnt, const_cnt;
-std::vector<SymDef*> glob_func, glob_vars;
+std::vector<SymDef*> glob_func, glob_vars, glob_get_methods;
 std::set<std::string> prohibited_var_names;
 
 SymDef* define_builtin_func_impl(const std::string& name, SymValAsmFunc* func_val) {
diff --git a/crypto/func/func.h b/crypto/func/func.h
index 0a79c712..faf71f5d 100644
--- a/crypto/func/func.h
+++ b/crypto/func/func.h
@@ -874,7 +874,7 @@ struct SymValConst : sym::SymValBase {
 };
 
 extern int glob_func_cnt, undef_func_cnt, glob_var_cnt;
-extern std::vector<SymDef*> glob_func, glob_vars;
+extern std::vector<SymDef*> glob_func, glob_vars, glob_get_methods;
 extern std::set<std::string> prohibited_var_names;
 
 /*
diff --git a/crypto/func/parse-func.cpp b/crypto/func/parse-func.cpp
index 4e73247c..f2e48f33 100644
--- a/crypto/func/parse-func.cpp
+++ b/crypto/func/parse-func.cpp
@@ -1579,6 +1579,11 @@ void parse_func_def(Lexer& lex) {
   if (is_get_method) {
     func_assert(method_id.is_null());
     method_id = calculate_method_id_by_func_name(func_name.str);
+    for (const SymDef* other : glob_get_methods) {
+      if (!td::cmp(dynamic_cast<const SymValFunc*>(other->value)->method_id, method_id)) {
+        lex.cur().error(PSTRING() << "GET methods hash collision: `" << other->name() << "` and `" + func_name.str + "` produce the same hash. Consider renaming one of these functions.");
+      }
+    }
   }
   TypeExpr* func_type = TypeExpr::new_map(extract_total_arg_type(arg_list), ret_type);
   func_type = compute_type_closure(func_type, type_vars);
@@ -1698,6 +1703,7 @@ void parse_func_def(Lexer& lex) {
       lex.cur().error("cannot set unknown function `"s + func_name.str + "` as a get method");
     }
     val->flags |= SymValFunc::flagGetMethod;
+    glob_get_methods.push_back(func_sym);
   }
   if (verbosity >= 1) {
     std::cerr << "new type of function " << func_name.str << " : " << func_type << std::endl;