[py] throw error when setting w3c to False #10908

py/selenium/webdriver/chromium/options.py

@@ -163,6 +163,17 @@ def to_capabilities(self) -> dict:
         """
         caps = self._caps
         chrome_options = self.experimental_options.copy()
+        if 'w3c' in chrome_options:
+            if chrome_options['w3c']:
+                warnings.warn(
+                    "Setting 'w3c: True' is redundant and will no longer be allowed",
+                    DeprecationWarning,
+                    stacklevel=2
+                )
+            else:
+                raise AttributeError('setting w3c to False is not allowed, '
+                                     'Please update to W3C Syntax: '
+                                     'https://www.selenium.dev/blog/2022/legacy-protocol-support/')
         if self.mobile_options:
             chrome_options.update(self.mobile_options)
         chrome_options["extensions"] = self.extensions

py/test/selenium/webdriver/chrome/options_tests.py

@@ -0,0 +1,25 @@
+import pytest
+
+from selenium import webdriver
+
+
+def test_w3c_true():
+    options = webdriver.ChromeOptions()
+    options.add_experimental_option("w3c", True)
+
+    chrome_kwargs = {'options': options}
+
+    with pytest.warns(DeprecationWarning, match="Setting 'w3c: True' is redundant"):
+        driver = webdriver.Chrome(**chrome_kwargs)
+
+    driver.quit()
+
+
+def test_w3c_false():
+    options = webdriver.ChromeOptions()
+    options.add_experimental_option("w3c", False)
+
+    chrome_kwargs = {'options': options}
+
+    with pytest.raises(AttributeError):
+        webdriver.Chrome(**chrome_kwargs)