avoid exponential :not() XPath in _xpath_match_condition

cssselect/xpath.py

@@ -329,12 +329,18 @@ def _xpath_match_condition(self, selector: Tree) -> str | None:
         axes for combinators.
         """
         if isinstance(selector, CombinedSelector):
-            axis = self._reverse_combinator_mapping[selector.combinator]
-            left = self._xpath_match_condition(selector.selector)
-            if left is not None:
-                axis = f"{axis}[{left}]"
+            steps = []
+            left: Tree = selector
+            while isinstance(left, CombinedSelector):
+                axis = self._reverse_combinator_mapping[left.combinator]
+                left = left.selector
+                condition = self._xpath_match_condition(
+                    left.subselector if isinstance(left, CombinedSelector) else left
+                )
+                steps.append(axis if condition is None else f"{axis}[{condition}]")
+            path = "/".join(steps)
             right = self._xpath_match_condition(selector.subselector)
-            return axis if right is None else f"({right}) and {axis}"
+            return path if right is None else f"({right}) and {path}"
         sub_xpath = self.xpath(selector)
         sub_xpath.add_name_test()
         return sub_xpath.condition or None

tests/test_cssselect.py

@@ -892,7 +892,14 @@ def xpath(css: str) -> str:
             "e[not((self::b) and preceding-sibling::*[self::a])]"
         )
         assert xpath("e:not(a > b > c)") == (
-            "e[not((self::c) and parent::*[(self::b) and parent::*[self::a]])]"
+            "e[not((self::c) and parent::*[self::b]/parent::*[self::a])]"
+        )
+        assert xpath("e:not(a b ~ c + d > f)") == (
+            "e[not((self::f) and parent::*[self::d]/preceding-sibling::*[1][self::c]"
+            "/preceding-sibling::*[self::b]/ancestor::*[self::a])]"
+        )
+        assert xpath("e:not(a * * f)") == (
+            "e[not((self::f) and ancestor::*/ancestor::*/ancestor::*[self::a])]"
         )
         assert xpath("e:not(.a > #b)") == (
             "e[not((@id = 'b') and parent::*[@class and contains(@class, 'a') and contains("
@@ -1760,6 +1767,8 @@ def pcss(main: str, *selectors: str, **kwargs: bool) -> list[str]:
             "seventh-li",
         ]
         assert pcss("li:not(#second-li ~ li)") == ["first-li", "second-li"]
+        assert pcss("li:not(div > ol li + li ~ li)") == ["first-li", "second-li"]
+        assert pcss("div:not(body > * * *)") == ["outer-div", "foobar-div"]
         assert pcss("li:has(div):nth-of-type(2)") == ["second-li"]
         assert pcss("li:has(div):first-of-type") == []
         assert pcss("ol:has(li):first-of-type") == ["first-ol"]