[3.15] gh-143493: fix cleanup on errors in codegen_comprehension (GH-156374)

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: iritkatriel

Python/codegen.c

@@ -4948,6 +4948,34 @@ pop_inlined_comprehension_state(compiler *c, location loc,
     return SUCCESS;
 }
 
+static int
+codegen_comprehension_init_container(compiler *c, location loc, int type,
+                                     int is_inlined)
+{
+    int op;
+    switch (type) {
+    case COMP_LISTCOMP:
+        op = BUILD_LIST;
+        break;
+    case COMP_SETCOMP:
+        op = BUILD_SET;
+        break;
+    case COMP_DICTCOMP:
+        op = BUILD_MAP;
+        break;
+    default:
+        PyErr_Format(PyExc_SystemError,
+                     "unknown comprehension type %d", type);
+        return ERROR;
+    }
+
+    ADDOP_I(c, loc, op, 0);
+    if (is_inlined) {
+        ADDOP_I(c, loc, SWAP, 2);
+    }
+    return SUCCESS;
+}
+
 static int
 codegen_comprehension(compiler *c, expr_ty e, int type,
                       identifier name, asdl_comprehension_seq *generators, expr_ty elt,
@@ -4986,19 +5014,22 @@ codegen_comprehension(compiler *c, expr_ty e, int type,
         if (type == COMP_GENEXP) {
             /* Insert GET_ITER before RETURN_GENERATOR.
                https://docs.python.org/3/reference/expressions.html#generator-expressions */
-            RETURN_IF_ERROR(
-                _PyInstructionSequence_InsertInstruction(
+            if (_PyInstructionSequence_InsertInstruction(
                     INSTR_SEQUENCE(c), 0,
-                    RESUME, RESUME_AT_GEN_EXPR_START, NO_LOCATION));
-            RETURN_IF_ERROR(
-                _PyInstructionSequence_InsertInstruction(
+                    RESUME, RESUME_AT_GEN_EXPR_START, NO_LOCATION) < 0) {
+                goto error_in_scope;
+            }
+            if (_PyInstructionSequence_InsertInstruction(
                     INSTR_SEQUENCE(c), 1,
-                    LOAD_FAST, 0, LOC(outermost->iter)));
-            RETURN_IF_ERROR(
-                _PyInstructionSequence_InsertInstruction(
+                    LOAD_FAST, 0, LOC(outermost->iter)) < 0) {
+                goto error_in_scope;
+            }
+            if (_PyInstructionSequence_InsertInstruction(
                     INSTR_SEQUENCE(c), 2,
                     outermost->is_async ? GET_AITER : GET_ITER,
-                    0, LOC(outermost->iter)));
+                    0, LOC(outermost->iter)) < 0) {
+                goto error_in_scope;
+            }
             iter_state = ITERATOR_ON_STACK;
         }
         else {
@@ -5008,27 +5039,9 @@ codegen_comprehension(compiler *c, expr_ty e, int type,
     Py_CLEAR(entry);
 
     if (type != COMP_GENEXP) {
-        int op;
-        switch (type) {
-        case COMP_LISTCOMP:
-            op = BUILD_LIST;
-            break;
-        case COMP_SETCOMP:
-            op = BUILD_SET;
-            break;
-        case COMP_DICTCOMP:
-            op = BUILD_MAP;
-            break;
-        default:
-            PyErr_Format(PyExc_SystemError,
-                         "unknown comprehension type %d", type);
+        if (codegen_comprehension_init_container(c, loc, type, is_inlined) < 0) {
             goto error_in_scope;
         }
-
-        ADDOP_I(c, loc, op, 0);
-        if (is_inlined) {
-            ADDOP_I(c, loc, SWAP, 2);
-        }
     }
     if (codegen_comprehension_generator(c, loc, generators, 0, 0,
                                         elt, val, type, iter_state) < 0) {
@@ -5043,7 +5056,7 @@ codegen_comprehension(compiler *c, expr_ty e, int type,
     }
 
     if (type != COMP_GENEXP) {
-        ADDOP(c, LOC(e), RETURN_VALUE);
+        ADDOP_IN_SCOPE(c, LOC(e), RETURN_VALUE);
     }
     if (type == COMP_GENEXP) {
         if (codegen_wrap_in_stopiteration_handler(c) < 0) {