From 53ea790caf50c6ca1d29247080c829d185b9e5c2 Mon Sep 17 00:00:00 2001
From: blueloveTH <blueloveTH@foxmail.com>
Date: Tue, 22 Aug 2023 23:34:39 +0800
Subject: [PATCH] reimpl `py_hash`

---
 docs/C-API/introduction.md |  2 +-
 src/pocketpy.cpp           | 21 +++++++--------------
 src/vm.cpp                 | 23 +++++++++++++++++++++--
 tests/99_builtin_func.py   | 14 +++++++-------
 4 files changed, 36 insertions(+), 24 deletions(-)

diff --git a/docs/C-API/introduction.md b/docs/C-API/introduction.md
index 33107251..1351be9f 100644
--- a/docs/C-API/introduction.md
+++ b/docs/C-API/introduction.md
@@ -16,7 +16,7 @@ Methods return a `bool` indicating if the operation succeeded or not.
 Special thanks for [@koltenpearson](https://github.com/koltenpearson)'s contribution.
 
 !!!
-**C-APIs are always stable and backward compatible** in order to support the second use case.
+C-APIs are always stable and backward compatible.
 !!!
 
 ### Basic functions
diff --git a/src/pocketpy.cpp b/src/pocketpy.cpp
index 3999e7df..b7f214b7 100644
--- a/src/pocketpy.cpp
+++ b/src/pocketpy.cpp
@@ -309,7 +309,6 @@ void init_builtins(VM* _vm) {
     });
 
     _vm->bind__eq__(_vm->tp_object, [](VM* vm, PyObject* lhs, PyObject* rhs) { return VAR(lhs == rhs); });
-    _vm->bind__hash__(_vm->tp_object, [](VM* vm, PyObject* obj) { return PK_BITS(obj); });
 
     _vm->cached_object__new__ = _vm->bind_constructor<1>("object", [](VM* vm, ArgsView args) {
         vm->check_non_tagged_type(args[0], vm->tp_type);
@@ -754,11 +753,6 @@ void init_builtins(VM* _vm) {
 
     _vm->bind_method<0>("list", "copy", PK_LAMBDA(VAR(_CAST(List, args[0]))));
 
-    _vm->bind__hash__(_vm->tp_list, [](VM* vm, PyObject* obj) {
-        vm->TypeError("unhashable type: 'list'");
-        return (i64)0;
-    });
-
     _vm->bind__add__(_vm->tp_list, [](VM* vm, PyObject* lhs, PyObject* rhs) {
         const List& self = _CAST(List&, lhs);
         const List& other = CAST(List&, rhs);
@@ -997,9 +991,13 @@ void init_builtins(VM* _vm) {
         return (i64)_CAST(MappingProxy&, obj).attr().size();
     });
 
-    _vm->bind__hash__(_vm->tp_mappingproxy, [](VM* vm, PyObject* obj) {
-        vm->TypeError("unhashable type: 'mappingproxy'");
-        return (i64)0;
+    _vm->bind__eq__(_vm->tp_mappingproxy, [](VM* vm, PyObject* obj, PyObject* other){
+        MappingProxy& a = _CAST(MappingProxy&, obj);
+        if(!is_non_tagged_type(other, vm->tp_mappingproxy)){
+            return vm->NotImplemented;
+        }
+        MappingProxy& b = _CAST(MappingProxy&, other);
+        return VAR(a.obj == b.obj);
     });
 
     _vm->bind__getitem__(_vm->tp_mappingproxy, [](VM* vm, PyObject* obj, PyObject* index) {
@@ -1057,11 +1055,6 @@ void init_builtins(VM* _vm) {
     _vm->bind__len__(_vm->tp_dict, [](VM* vm, PyObject* obj) {
         return (i64)_CAST(Dict&, obj).size();
     });
-    
-    _vm->bind__hash__(_vm->tp_dict, [](VM* vm, PyObject* obj) {
-        vm->TypeError("unhashable type: 'dict'");
-        return (i64)0;
-    });
 
     _vm->bind__getitem__(_vm->tp_dict, [](VM* vm, PyObject* obj, PyObject* index) {
         Dict& self = _CAST(Dict&, obj);
diff --git a/src/vm.cpp b/src/vm.cpp
index fe3b6b80..13ba14bd 100644
--- a/src/vm.cpp
+++ b/src/vm.cpp
@@ -350,10 +350,29 @@ void VM::parse_int_slice(const Slice& s, int length, int& start, int& stop, int&
 }
 
 i64 VM::py_hash(PyObject* obj){
+    // https://docs.python.org/3.10/reference/datamodel.html#object.__hash__
     const PyTypeInfo* ti = _inst_type_info(obj);
     if(ti->m__hash__) return ti->m__hash__(this, obj);
-    PyObject* ret = call_method(obj, __hash__);
-    return CAST(i64, ret);
+
+    PyObject* self;
+    PyObject* f = get_unbound_method(obj, __hash__, &self, false);
+    if(f != nullptr){
+        PyObject* ret = call_method(self, f);
+        return CAST(i64, ret);
+    }
+    // it flow reaches here, obj must not be the trivial `object` type
+    bool has_custom_eq = false;
+    if(ti->m__eq__) has_custom_eq = true;
+    else{
+        f = get_unbound_method(obj, __eq__, &self, false);
+        has_custom_eq = f != _t(tp_object)->attr(__eq__);
+    }
+    if(has_custom_eq){
+        TypeError(fmt("unhashable type: ", ti->name.escape()));
+        return 0;
+    }else{
+        return PK_BITS(obj);
+    }
 }
 
 PyObject* VM::format(Str spec, PyObject* obj){
diff --git a/tests/99_builtin_func.py b/tests/99_builtin_func.py
index c559c64c..0e53819e 100644
--- a/tests/99_builtin_func.py
+++ b/tests/99_builtin_func.py
@@ -207,12 +207,12 @@ def f():
 assert type(hash(a)) is int
 
 # 测试不可哈希对象
-# try:
-#     hash({1:1})
-#     print('未能拦截错误')
-#     exit(1)
-# except:
-#     pass
+try:
+    hash({1:1})
+    print('未能拦截错误')
+    exit(1)
+except:
+    pass
 
 try:
     hash([1])
@@ -842,7 +842,7 @@ try:
     hash(my_mappingproxy)
     print('未能拦截错误, 在测试 mappingproxy.__hash__')
     exit(1)
-except:
+except TypeError:
     pass
 
 # 未完全测试准确性-----------------------------------------------