fix stack effects of make_function, build_slice, and format_value ope…

pytest/test_stack_effect.py

@@ -175,5 +175,29 @@ def test_one(xdis_args, dis_args, has_arg: bool) -> None:
     return
 
 
+def test_stack_effect_operand_dependent() -> None:
+    """Check stack effects of MAKE_FUNCTION, FORMAT_VALUE, and BUILD_SLICE
+    for operands whose bits change how many items are popped.
+    """
+    for version in ((3, 6), (3, 10)):
+        opc = get_opcode(version, False)
+        for oparg, effect in ((11, -4), (12, -3), (15, -5)):
+            assert xstack_effect(opc.opmap["MAKE_FUNCTION"], opc, oparg) == effect
+
+    for version in ((3, 11), (3, 12)):
+        opc = get_opcode(version, False)
+        for oparg, effect in ((3, -2), (4, -1), (8, -1), (9, -2), (10, -2), (11, -3), (15, -4)):
+            assert xstack_effect(opc.opmap["MAKE_FUNCTION"], opc, oparg) == effect
+
+    for version in ((3, 6), (3, 12)):
+        opc = get_opcode(version, False)
+        assert xstack_effect(opc.opmap["FORMAT_VALUE"], opc, 0) == 0
+        assert xstack_effect(opc.opmap["FORMAT_VALUE"], opc, 4) == -1
+
+    for version in ((3, 6), (3, 13)):
+        opc = get_opcode(version, False)
+        assert xstack_effect(opc.opmap["BUILD_SLICE"], opc, 3) == -2
+
+
 if __name__ == "__main__":
     test_stack_effect_fixed()

xdis/cross_dis.py

@@ -508,21 +508,27 @@ def xstack_effect(opcode, opc, oparg: int = 0, jump=None):
         "BUILD_TUPLE",
     ) and version_tuple >= (3, 12):
         return 1 - oparg
-    elif opname in ("BUILD_SLICE") and version_tuple <= (2, 7):
+    elif opname in ("BUILD_SLICE") and version_tuple < (3, 14):
+        # this was 2.7 only, but 3.0 through 3.13 also pop the step in a[x:y:z]
+        # (3.14 changed BUILD_SLICE and its opcode table already handles it)
         return -2 if oparg == 3 else -1
+    elif opname == "FORMAT_VALUE" and version_tuple >= (3, 6):
+        # f"{x:>10}" also pops the format spec; the table only counted the value
+        return -1 if oparg & 0x04 else 0
     elif opname == "LOAD_ATTR" and version_tuple >= (3, 12):
         return 1 if oparg & 1 else 0
     elif opname == "MAKE_FUNCTION":
         if version_tuple >= (3, 5):
-            if 0 <= oparg <= 10:
+            # was 10, but a nested function with defaults, kwdefaults, and a closure is 11 (15 with annotations)
+            if 0 <= oparg <= (10 if version_tuple == (3, 5) else 15):
                 if version_tuple == (3, 5):
                     return [-1, -2, -3, -3, -2, -3, -3, -4, -2, -3, -3, -4][oparg]
                 elif (3, 6) <= version_tuple < (3, 11):
-                    return [-1, -2, -2, -3, -2, -3, -3, -4, -2, -3, -3, -4][oparg]
-                elif 0 <= oparg <= 2:
-                    return [0, -1, -1][oparg]
+                    return [-1, -2, -2, -3, -2, -3, -3, -4, -2, -3, -3, -4, -3, -4, -4, -5][oparg]
                 else:
-                    return None
+                    # only flags 0-2 were handled, so closures and annotations gave None;
+                    # this is the 3.6-3.10 table plus one since 3.11 no longer pops the qualname
+                    return [0, -1, -1, -2, -1, -2, -2, -3, -1, -2, -2, -3, -2, -3, -3, -4][oparg]
             else:
                 return None
     elif opname in ("CALL", "INSTRUMENTED_CALL") and version_tuple >= (3, 12):