fix(webdriver): address review feedback on cache warmup WebDriver changes

- Fix _auth() to authenticate self._driver in-place instead of creating
  a second, leaked driver (critical bug: persistent driver was never authenticated)
- Replace assert with explicit RuntimeError for driver creation failure
- Fix get_dash_url() to strip trailing slash from WEBDRIVER_BASEURL to
  avoid double-slash URLs (e.g. http://host//superset/dashboard/1/)
- Fix BaseScreenshot.get_screenshot() to call driver.destroy() in a
  try/finally block, preventing Selenium process leaks for one-off screenshots
- Fix webdriver_pool._destroy_driver() to directly call close()/quit()
  on the raw WebDriver since destroy() is now an instance method, not static

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

superset/mcp_service/screenshot/webdriver_pool.py

@@ -228,7 +228,11 @@ class WebDriverPool:
     def _destroy_driver(self, pooled_driver: PooledWebDriver) -> None:
         """Safely destroy a WebDriver instance"""
         try:
-            WebDriverSelenium.destroy(pooled_driver.driver)
+            try:
+                pooled_driver.driver.close()
+            except Exception:  # pylint: disable=broad-except  # noqa: S110
+                pass
+            pooled_driver.driver.quit()
             self._stats["destroyed"] += 1
             logger.debug("Destroyed WebDriver instance")
         except Exception as e:

superset/tasks/cache.py

@@ -48,7 +48,7 @@ def get_dash_url(dashboard: Dashboard) -> str:
             "{SUPERSET_WEBSERVER_ADDRESS}:"
             "{SUPERSET_WEBSERVER_PORT}".format(**current_app.config)
         )
-        return f"{baseurl}{dashboard.url}"
+        return f"{baseurl.rstrip('/')}{dashboard.url}"
 
 
 class Strategy:  # pylint: disable=too-few-public-methods

superset/utils/screenshots.py

@@ -212,7 +212,11 @@ class BaseScreenshot:
         self, user: User, window_size: WindowSize | None = None
     ) -> bytes | None:
         driver = self.driver(window_size, user)
-        self.screenshot = driver.get_screenshot(self.url, self.element)
+        try:
+            self.screenshot = driver.get_screenshot(self.url, self.element)
+        finally:
+            if isinstance(driver, WebDriverSelenium):
+                driver.destroy()
         return self.screenshot
 
     def get_cache_key(

superset/utils/webdriver.py

@@ -419,7 +419,8 @@ class WebDriverSelenium(WebDriverProxy):
     def driver(self) -> WebDriver:
         if not self._driver:
             self._driver = self._create()
-            assert self._driver  # for mypy
+            if not self._driver:
+                raise RuntimeError("WebDriver creation failed")
             self._driver.set_window_size(*self._window)
             if self._user:
                 self._auth(self._user)
@@ -558,10 +559,11 @@ class WebDriverSelenium(WebDriverProxy):
         logger.debug("Init selenium driver")
         return driver_class(**kwargs)
 
-    def _auth(self, user: User) -> WebDriver:
-        driver = self._create()
-        return machine_auth_provider_factory.instance.authenticate_webdriver(
-            driver, user
+    def _auth(self, user: User) -> None:
+        """Authenticate the persistent driver in-place."""
+        assert self._driver is not None
+        machine_auth_provider_factory.instance.authenticate_webdriver(
+            self._driver, user
         )
 
     def _destroy(self, tries: int = 2) -> None: