Merge c048ec9faf4bfe02da004dce69471897933c3617 into 2600eb535296ff1063e9e674ce61be9a90001798

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

include/typings/stdc.pyi

@@ -5,7 +5,7 @@ intptr = int
 def malloc(size: int) -> intptr: ...
 def free(ptr: intptr) -> None: ...
 
-def memcpy(dst: intptr, src: intptr, n: int) -> None: ...
+def memcpy(dst: intptr, src: intptr | bytes, n: int) -> None: ...
 def memset(s: intptr, c: int, n: int) -> None: ...
 def memcmp(s1: intptr, s2: intptr, n: int) -> int: ...
 

src/compiler/compiler.c

@@ -2847,6 +2847,8 @@ 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)) {
@@ -2855,17 +2857,33 @@ 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();
         }
         ///////////

src/modules/lz4.c

@@ -2,6 +2,7 @@
 
 #include <string.h>
 #include <assert.h>
+#include "pocketpy/common/utils.h"
 #include "pocketpy/pocketpy.h"
 #include "lz4/lib/lz4.h"
 
@@ -10,13 +11,13 @@ static bool lz4_compress(int argc, py_Ref argv) {
     PY_CHECK_ARG_TYPE(0, tp_bytes);
     int src_size;
     const void* src = py_tobytes(argv, &src_size);
-    int dst_capacity = LZ4_compressBound(src_size);
-    char* p = (char*)py_newbytes(py_retval(), sizeof(int) + dst_capacity);
-    memcpy(p, &src_size, sizeof(int));
-    char* dst = p + sizeof(int);
+    uint32_t dst_capacity = LZ4_compressBound(src_size);
+    char* p = (char*)py_newbytes(py_retval(), sizeof(uint32_t) + dst_capacity);
+    memcpy(p, &src_size, sizeof(uint32_t));
+    char* dst = p + sizeof(uint32_t);
     int dst_size = LZ4_compress_default(src, dst, src_size, dst_capacity);
     if(dst_size <= 0) return ValueError("LZ4 compression failed");
-    py_bytes_resize(py_retval(), sizeof(int) + dst_size);
+    py_bytes_resize(py_retval(), sizeof(uint32_t) + dst_size);
     return true;
 }
 
@@ -24,15 +25,16 @@ static bool lz4_decompress(int argc, py_Ref argv) {
     PY_CHECK_ARGC(1);
     PY_CHECK_ARG_TYPE(0, tp_bytes);
     int total_size;
-    const int* p = (int*)py_tobytes(argv, &total_size);
+    const uint32_t* p = (uint32_t*)py_tobytes(argv, &total_size);
     const char* src = (const char*)(p + 1);
-    if(total_size < sizeof(int)) return ValueError("invalid LZ4 data");
-    int uncompressed_size = *p;
-    if(uncompressed_size < 0) return ValueError("invalid LZ4 data");
+    if(total_size < sizeof(uint32_t)) return ValueError("invalid LZ4 data");
+    uint32_t uncompressed_size;
+    memcpy(&uncompressed_size, p, sizeof(uint32_t));
+    if(uncompressed_size >= INT32_MAX) return ValueError("invalid LZ4 data");
     char* dst = (char*)py_newbytes(py_retval(), uncompressed_size);
-    int dst_size = LZ4_decompress_safe(src, dst, total_size - sizeof(int), uncompressed_size);
+    int dst_size = LZ4_decompress_safe(src, dst, total_size - sizeof(uint32_t), uncompressed_size);
     if(dst_size < 0) return ValueError("LZ4 decompression failed");
-    assert(dst_size == uncompressed_size);
+    c11__rtassert(dst_size == uncompressed_size);
     return true;
 }
 

src/modules/stdc.c

@@ -124,12 +124,19 @@ static bool stdc_free(int argc, py_Ref argv) {
 
 static bool stdc_memcpy(int argc, py_Ref argv) {
     PY_CHECK_ARGC(3);
-    PY_CHECK_ARG_TYPE(0, tp_int);
-    PY_CHECK_ARG_TYPE(1, tp_int);
-    PY_CHECK_ARG_TYPE(2, tp_int);
+    PY_CHECK_ARG_TYPE(0, tp_int);   // dst
     void* dst = (void*)(intptr_t)py_toint(&argv[0]);
-    void* src = (void*)(intptr_t)py_toint(&argv[1]);
+    PY_CHECK_ARG_TYPE(2, tp_int);   // n
     py_i64 n = py_toint(&argv[2]);
+    void* src;
+    if(py_istype(&argv[1], tp_bytes)) {
+        int size;
+        src = py_tobytes(&argv[1], &size);
+        if(size < n) n = size;
+    } else {
+        PY_CHECK_ARG_TYPE(1, tp_int);   // src
+        src = (void*)(intptr_t)py_toint(&argv[1]);
+    }
     memcpy(dst, src, (size_t)n);
     py_newnone(py_retval());
     return true;

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}"
+