Merge c048ec9faf4bfe02da004dce69471897933c3617 into 7d9c3c3df0bfdbc631c54b12ad70a9bd1f06984b

Problem: When an exception occurs in a WITH block, __exit__ was not called,
preventing proper cleanup of context managers.

Solution:
1. Wrap WITH block body in try-except structure
2. On normal exit: call __exit__(None, None, None)
3. On exception: call __exit__ with exception info before re-raising

Changes:
- compiler.c: Wrap WITH body in try-except, ensure __exit__ called in both paths
- ceval.c: Update OP_WITH_EXIT to accept three arguments (exc_type, exc_val, exc_tb)
- tests/520_context.py: Add test to verify __exit__ called on exceptions

python/operator.py

@@ -53,3 +53,9 @@ class attrgetter:
         self.attr = attr
     def __call__(self, obj):
         return getattr(obj, self.attr)
+
+class itemgetter:
+    def __init__(self, item):
+        self.item = item
+    def __call__(self, obj):
+        return obj[self.item]

python/typing.py

@@ -57,5 +57,7 @@ assert_never = lambda x: x
 
 TypedDict = dict
 NotRequired = _PLACEHOLDER
+ReadOnly = _PLACEHOLDER
+Required = _PLACEHOLDER
 
 cast = lambda _, val: val

src/common/_generated.c

@@ -10,8 +10,8 @@ const char kPythonLibs_datetime[] = "from time import localtime\nimport operator
 const char kPythonLibs_functools[] = "class cache:\n    def __init__(self, f):\n        self.f = f\n        self.cache = {}\n\n    def __call__(self, *args):\n        if args not in self.cache:\n            self.cache[args] = self.f(*args)\n        return self.cache[args]\n    \nclass lru_cache:\n    def __init__(self, maxsize=128):\n        self.maxsize = maxsize\n        self.cache = {}\n\n    def __call__(self, f):\n        def wrapped(*args):\n            if args in self.cache:\n                res = self.cache.pop(args)\n                self.cache[args] = res\n                return res\n            \n            res = f(*args)\n            if len(self.cache) >= self.maxsize:\n                first_key = next(iter(self.cache))\n                self.cache.pop(first_key)\n            self.cache[args] = res\n            return res\n        return wrapped\n    \ndef reduce(function, sequence, initial=...):\n    it = iter(sequence)\n    if initial is ...:\n        try:\n            value = next(it)\n        except StopIteration:\n            raise TypeError(\"reduce() of empty sequence with no initial value\")\n    else:\n        value = initial\n    for element in it:\n        value = function(value, element)\n    return value\n\nclass partial:\n    def __init__(self, f, *args, **kwargs):\n        self.f = f\n        if not callable(f):\n            raise TypeError(\"the first argument must be callable\")\n        self.args = args\n        self.kwargs = kwargs\n\n    def __call__(self, *args, **kwargs):\n        kwargs.update(self.kwargs)\n        return self.f(*self.args, *args, **kwargs)\n\n";
 const char kPythonLibs_heapq[] = "# Heap queue algorithm (a.k.a. priority queue)\ndef heappush(heap, item):\n    \"\"\"Push item onto heap, maintaining the heap invariant.\"\"\"\n    heap.append(item)\n    _siftdown(heap, 0, len(heap)-1)\n\ndef heappop(heap):\n    \"\"\"Pop the smallest item off the heap, maintaining the heap invariant.\"\"\"\n    lastelt = heap.pop()    # raises appropriate IndexError if heap is empty\n    if heap:\n        returnitem = heap[0]\n        heap[0] = lastelt\n        _siftup(heap, 0)\n        return returnitem\n    return lastelt\n\ndef heapreplace(heap, item):\n    \"\"\"Pop and return the current smallest value, and add the new item.\n\n    This is more efficient than heappop() followed by heappush(), and can be\n    more appropriate when using a fixed-size heap.  Note that the value\n    returned may be larger than item!  That constrains reasonable uses of\n    this routine unless written as part of a conditional replacement:\n\n        if item > heap[0]:\n            item = heapreplace(heap, item)\n    \"\"\"\n    returnitem = heap[0]    # raises appropriate IndexError if heap is empty\n    heap[0] = item\n    _siftup(heap, 0)\n    return returnitem\n\ndef heappushpop(heap, item):\n    \"\"\"Fast version of a heappush followed by a heappop.\"\"\"\n    if heap and heap[0] < item:\n        item, heap[0] = heap[0], item\n        _siftup(heap, 0)\n    return item\n\ndef heapify(x):\n    \"\"\"Transform list into a heap, in-place, in O(len(x)) time.\"\"\"\n    n = len(x)\n    # Transform bottom-up.  The largest index there's any point to looking at\n    # is the largest with a child index in-range, so must have 2*i + 1 < n,\n    # or i < (n-1)/2.  If n is even = 2*j, this is (2*j-1)/2 = j-1/2 so\n    # j-1 is the largest, which is n//2 - 1.  If n is odd = 2*j+1, this is\n    # (2*j+1-1)/2 = j so j-1 is the largest, and that's again n//2-1.\n    for i in reversed(range(n//2)):\n        _siftup(x, i)\n\n# 'heap' is a heap at all indices >= startpos, except possibly for pos.  pos\n# is the index of a leaf with a possibly out-of-order value.  Restore the\n# heap invariant.\ndef _siftdown(heap, startpos, pos):\n    newitem = heap[pos]\n    # Follow the path to the root, moving parents down until finding a place\n    # newitem fits.\n    while pos > startpos:\n        parentpos = (pos - 1) >> 1\n        parent = heap[parentpos]\n        if newitem < parent:\n            heap[pos] = parent\n            pos = parentpos\n            continue\n        break\n    heap[pos] = newitem\n\ndef _siftup(heap, pos):\n    endpos = len(heap)\n    startpos = pos\n    newitem = heap[pos]\n    # Bubble up the smaller child until hitting a leaf.\n    childpos = 2*pos + 1    # leftmost child position\n    while childpos < endpos:\n        # Set childpos to index of smaller child.\n        rightpos = childpos + 1\n        if rightpos < endpos and not heap[childpos] < heap[rightpos]:\n            childpos = rightpos\n        # Move the smaller child up.\n        heap[pos] = heap[childpos]\n        pos = childpos\n        childpos = 2*pos + 1\n    # The leaf at pos is empty now.  Put newitem there, and bubble it up\n    # to its final resting place (by sifting its parents down).\n    heap[pos] = newitem\n    _siftdown(heap, startpos, pos)";
 const char kPythonLibs_linalg[] = "from vmath import *";
-const char kPythonLibs_operator[] = "# https://docs.python.org/3/library/operator.html#mapping-operators-to-functions\n\ndef le(a, b): return a <= b\ndef lt(a, b): return a < b\ndef ge(a, b): return a >= b\ndef gt(a, b): return a > b\ndef eq(a, b): return a == b\ndef ne(a, b): return a != b\n\ndef and_(a, b): return a & b\ndef or_(a, b): return a | b\ndef xor(a, b): return a ^ b\ndef invert(a): return ~a\ndef lshift(a, b): return a << b\ndef rshift(a, b): return a >> b\n\ndef is_(a, b): return a is b\ndef is_not(a, b): return a is not b\ndef not_(a): return not a\ndef truth(a): return bool(a)\ndef contains(a, b): return b in a\n\ndef add(a, b): return a + b\ndef sub(a, b): return a - b\ndef mul(a, b): return a * b\ndef truediv(a, b): return a / b\ndef floordiv(a, b): return a // b\ndef mod(a, b): return a % b\ndef pow(a, b): return a ** b\ndef neg(a): return -a\ndef matmul(a, b): return a @ b\n\ndef getitem(a, b): return a[b]\ndef setitem(a, b, c): a[b] = c\ndef delitem(a, b): del a[b]\n\ndef iadd(a, b): a += b; return a\ndef isub(a, b): a -= b; return a\ndef imul(a, b): a *= b; return a\ndef itruediv(a, b): a /= b; return a\ndef ifloordiv(a, b): a //= b; return a\ndef imod(a, b): a %= b; return a\n# def ipow(a, b): a **= b; return a\n# def imatmul(a, b): a @= b; return a\ndef iand(a, b): a &= b; return a\ndef ior(a, b): a |= b; return a\ndef ixor(a, b): a ^= b; return a\ndef ilshift(a, b): a <<= b; return a\ndef irshift(a, b): a >>= b; return a\n\nclass attrgetter:\n    def __init__(self, attr):\n        self.attr = attr\n    def __call__(self, obj):\n        return getattr(obj, self.attr)\n";
-const char kPythonLibs_typing[] = "class _Placeholder:\n    def __init__(self, *args, **kwargs):\n        pass\n    def __getitem__(self, *args):\n        return self\n    def __call__(self, *args, **kwargs):\n        return self\n    def __and__(self, other):\n        return self\n    def __or__(self, other):\n        return self\n    def __xor__(self, other):\n        return self\n\n\n_PLACEHOLDER = _Placeholder()\n\nSequence = _PLACEHOLDER\nList = _PLACEHOLDER\nDict = _PLACEHOLDER\nTuple = _PLACEHOLDER\nSet = _PLACEHOLDER\nAny = _PLACEHOLDER\nUnion = _PLACEHOLDER\nOptional = _PLACEHOLDER\nCallable = _PLACEHOLDER\nType = _PLACEHOLDER\nTypeAlias = _PLACEHOLDER\nNewType = _PLACEHOLDER\n\nClassVar = _PLACEHOLDER\n\nLiteral = _PLACEHOLDER\nLiteralString = _PLACEHOLDER\n\nIterable = _PLACEHOLDER\nGenerator = _PLACEHOLDER\nIterator = _PLACEHOLDER\n\nHashable = _PLACEHOLDER\n\nTypeVar = _PLACEHOLDER\nSelf = _PLACEHOLDER\n\nProtocol = object\nGeneric = object\nNever = object\n\nTYPE_CHECKING = False\n\n# decorators\noverload = lambda x: x\nfinal = lambda x: x\n\n# exhaustiveness checking\nassert_never = lambda x: x\n\nTypedDict = dict\nNotRequired = _PLACEHOLDER\n\ncast = lambda _, val: val\n";
+const char kPythonLibs_operator[] = "# https://docs.python.org/3/library/operator.html#mapping-operators-to-functions\n\ndef le(a, b): return a <= b\ndef lt(a, b): return a < b\ndef ge(a, b): return a >= b\ndef gt(a, b): return a > b\ndef eq(a, b): return a == b\ndef ne(a, b): return a != b\n\ndef and_(a, b): return a & b\ndef or_(a, b): return a | b\ndef xor(a, b): return a ^ b\ndef invert(a): return ~a\ndef lshift(a, b): return a << b\ndef rshift(a, b): return a >> b\n\ndef is_(a, b): return a is b\ndef is_not(a, b): return a is not b\ndef not_(a): return not a\ndef truth(a): return bool(a)\ndef contains(a, b): return b in a\n\ndef add(a, b): return a + b\ndef sub(a, b): return a - b\ndef mul(a, b): return a * b\ndef truediv(a, b): return a / b\ndef floordiv(a, b): return a // b\ndef mod(a, b): return a % b\ndef pow(a, b): return a ** b\ndef neg(a): return -a\ndef matmul(a, b): return a @ b\n\ndef getitem(a, b): return a[b]\ndef setitem(a, b, c): a[b] = c\ndef delitem(a, b): del a[b]\n\ndef iadd(a, b): a += b; return a\ndef isub(a, b): a -= b; return a\ndef imul(a, b): a *= b; return a\ndef itruediv(a, b): a /= b; return a\ndef ifloordiv(a, b): a //= b; return a\ndef imod(a, b): a %= b; return a\n# def ipow(a, b): a **= b; return a\n# def imatmul(a, b): a @= b; return a\ndef iand(a, b): a &= b; return a\ndef ior(a, b): a |= b; return a\ndef ixor(a, b): a ^= b; return a\ndef ilshift(a, b): a <<= b; return a\ndef irshift(a, b): a >>= b; return a\n\nclass attrgetter:\n    def __init__(self, attr):\n        self.attr = attr\n    def __call__(self, obj):\n        return getattr(obj, self.attr)\n\nclass itemgetter:\n    def __init__(self, item):\n        self.item = item\n    def __call__(self, obj):\n        return obj[self.item]\n";
+const char kPythonLibs_typing[] = "class _Placeholder:\n    def __init__(self, *args, **kwargs):\n        pass\n    def __getitem__(self, *args):\n        return self\n    def __call__(self, *args, **kwargs):\n        return self\n    def __and__(self, other):\n        return self\n    def __or__(self, other):\n        return self\n    def __xor__(self, other):\n        return self\n\n\n_PLACEHOLDER = _Placeholder()\n\nSequence = _PLACEHOLDER\nList = _PLACEHOLDER\nDict = _PLACEHOLDER\nTuple = _PLACEHOLDER\nSet = _PLACEHOLDER\nAny = _PLACEHOLDER\nUnion = _PLACEHOLDER\nOptional = _PLACEHOLDER\nCallable = _PLACEHOLDER\nType = _PLACEHOLDER\nTypeAlias = _PLACEHOLDER\nNewType = _PLACEHOLDER\n\nClassVar = _PLACEHOLDER\n\nLiteral = _PLACEHOLDER\nLiteralString = _PLACEHOLDER\n\nIterable = _PLACEHOLDER\nGenerator = _PLACEHOLDER\nIterator = _PLACEHOLDER\n\nHashable = _PLACEHOLDER\n\nTypeVar = _PLACEHOLDER\nSelf = _PLACEHOLDER\n\nProtocol = object\nGeneric = object\nNever = object\n\nTYPE_CHECKING = False\n\n# decorators\noverload = lambda x: x\nfinal = lambda x: x\n\n# exhaustiveness checking\nassert_never = lambda x: x\n\nTypedDict = dict\nNotRequired = _PLACEHOLDER\nReadOnly = _PLACEHOLDER\nRequired = _PLACEHOLDER\n\ncast = lambda _, val: val\n";
 
 const char* load_kPythonLib(const char* name) {
     if (strchr(name, '.') != NULL) return NULL;

src/compiler/compiler.c

@@ -2801,6 +2801,8 @@ static Error* compile_stmt(Compiler* self) {
         case TK_WITH: {
             check(EXPR(self));  // [ <expr> ]
             Ctx__s_emit_top(ctx());
+            // Save context manager for later __exit__ call
+            Ctx__emit_(ctx(), OP_DUP_TOP, BC_NOARG, prev()->line);
             Ctx__enter_block(ctx(), CodeBlockType_WITH);
             NameExpr* as_name = NULL;
             if(match(TK_AS)) {
@@ -2809,17 +2811,33 @@ static Error* compile_stmt(Compiler* self) {
                 as_name = NameExpr__new(prev()->line, name, name_scope(self));
             }
             Ctx__emit_(ctx(), OP_WITH_ENTER, BC_NOARG, prev()->line);
-            // [ <expr> <expr>.__enter__() ]
             if(as_name) {
                 bool ok = vtemit_store((Expr*)as_name, ctx());
                 vtdelete((Expr*)as_name);
                 if(!ok) return SyntaxError(self, "invalid syntax");
             } else {
-                // discard `__enter__()`'s return value
                 Ctx__emit_(ctx(), OP_POP_TOP, BC_NOARG, BC_KEEPLINE);
             }
+            // Wrap body in try-except to ensure __exit__ is called even on exception
+            Ctx__enter_block(ctx(), CodeBlockType_TRY);
+            Ctx__emit_(ctx(), OP_BEGIN_TRY, BC_NOARG, prev()->line);
             check(compile_block_body(self));
+            Ctx__emit_(ctx(), OP_END_TRY, BC_NOARG, BC_KEEPLINE);
+            // Normal exit: call __exit__(None, None, None)
+            Ctx__emit_(ctx(), OP_LOAD_NONE, BC_NOARG, prev()->line);
+            Ctx__emit_(ctx(), OP_LOAD_NONE, BC_NOARG, prev()->line);
+            Ctx__emit_(ctx(), OP_LOAD_NONE, BC_NOARG, prev()->line);
             Ctx__emit_(ctx(), OP_WITH_EXIT, BC_NOARG, prev()->line);
+            int jump_patch = Ctx__emit_(ctx(), OP_JUMP_FORWARD, BC_NOARG, BC_KEEPLINE);
+            Ctx__exit_block(ctx());
+            // Exception handler: call __exit__ with exception info, then re-raise
+            Ctx__emit_(ctx(), OP_PUSH_EXCEPTION, BC_NOARG, BC_KEEPLINE);
+            Ctx__emit_(ctx(), OP_LOAD_NONE, BC_NOARG, BC_KEEPLINE);  // exc_type
+            Ctx__emit_(ctx(), OP_ROT_TWO, BC_NOARG, BC_KEEPLINE);     // reorder: [cm, None, exc]
+            Ctx__emit_(ctx(), OP_LOAD_NONE, BC_NOARG, BC_KEEPLINE);  // exc_tb
+            Ctx__emit_(ctx(), OP_WITH_EXIT, BC_NOARG, prev()->line);
+            Ctx__emit_(ctx(), OP_RE_RAISE, BC_NOARG, BC_KEEPLINE);
+            Ctx__patch_jump(ctx(), jump_patch);
             Ctx__exit_block(ctx());
         } break;
         /*************************************************/

src/interpreter/ceval.c

@@ -1122,14 +1122,35 @@ __NEXT_STEP:
             DISPATCH();
         }
         case OP_WITH_EXIT: {
-            // [expr]
-            py_push(TOP());
+            // Stack: [cm, exc_type, exc_val, exc_tb]
+            // Call cm.__exit__(exc_type, exc_val, exc_tb)
+            py_Ref exc_tb = TOP();
+            py_Ref exc_val = SECOND();
+            py_Ref exc_type = THIRD();
+            py_Ref cm = FOURTH();
+            
+            // Save all values from stack
+            py_TValue saved_cm = *cm;
+            py_TValue saved_exc_type = *exc_type;
+            py_TValue saved_exc_val = *exc_val;
+            py_TValue saved_exc_tb = *exc_tb;
+            self->stack.sp -= 4;
+            
+            // Push cm and get __exit__ method
+            py_push(&saved_cm);
             if(!py_pushmethod(__exit__)) {
-                TypeError("'%t' object does not support the context manager protocol", TOP()->type);
+                TypeError("'%t' object does not support the context manager protocol", saved_cm.type);
                 goto __ERROR;
             }
-            if(!py_vectorcall(0, 0)) goto __ERROR;
-            POP();
+            
+            // Push arguments: exc_type, exc_val, exc_tb
+            PUSH(&saved_exc_type);
+            PUSH(&saved_exc_val);
+            PUSH(&saved_exc_tb);
+            
+            // Call __exit__(exc_type, exc_val, exc_tb)
+            if(!py_vectorcall(3, 0)) goto __ERROR;
+            py_pop();  // discard return value
             DISPATCH();
         }
         ///////////

tests/520_context.py

@@ -27,4 +27,29 @@ assert path == ['enter', 'in', 'exit']
 
 path.clear()
 
+# Test that __exit__ is called even when an exception occurs
+class B:
+    def __init__(self):
+        self.path = []
+    
+    def __enter__(self):
+        path.append('enter')
+        return self
+    
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        path.append('exit')
+        if exc_type is not None:
+            path.append('exception')
+        return False  # propagate exception
+
+try:
+    with B():
+        path.append('before_raise')
+        raise ValueError('test')
+        path.append('after_raise')  # should not be reached
+except ValueError:
+    pass
+
+assert path == ['enter', 'before_raise', 'exit', 'exception'], f"Expected ['enter', 'before_raise', 'exit', 'exception'], got {path}"
+