Make execute_javascript throw a JavascriptError if the javascript failed.

- Require this interface to use returnByValue = True, because we want to help the user by getting the value out of the result object. - We should either use returnByValue or return the result not the value. I chose the latter because that's what any existing user expects it to do.

Author: JonathanWylie

browserdebuggertools/chrome/interface.py

@@ -4,7 +4,7 @@
 from typing import Optional
 
 from browserdebuggertools import models
-from browserdebuggertools.exceptions import TargetNotFoundError
+from browserdebuggertools.exceptions import TargetNotFoundError, JavascriptError
 from browserdebuggertools.targets_manager import TargetsManager
 
 logging.basicConfig(format='%(levelname)s:%(message)s')
@@ -151,11 +151,22 @@ def stop_page_load(self):
  return self.execute("Page", "stopLoading")
 
  def execute_javascript(self, script, **kwargs):
+ if "returnByValue" in kwargs:
+ if not kwargs["returnByValue"]:
+ raise ValueError(
+ "If want returnByValue as False, "
+ f"use .execute('runtime', 'evaluate', "
+ f"{{'expression': '{script}', returnByValue: False}}) directly"
+ )
  params = {
  "expression": script,
+ "returnByValue": True
  }
  params.update(kwargs)
+
  result = self.execute("Runtime", "evaluate", params)["result"]
+ if result.get("subtype") == "error":
+ raise JavascriptError(f"{result['description']}")
 
  return result.get("value")
 

browserdebuggertools/exceptions.py

@@ -41,6 +41,10 @@ class JavascriptDialogNotFoundError(NotFoundError):
  pass
 
 
+class JavascriptError(DevToolsException):
+ pass
+
+
 class MaxRetriesException(DevToolsException):
  pass
 

tests/e2etests/chrome/test_interface.py

@@ -563,9 +563,15 @@ def test(self: Union[TestCase, ChromeInterfaceTest]):
 
  # Block any new document requests and open url in a new tab
  self.devtools_client.block_main_frames()
- self.devtools_client.execute_javascript(
- f"window.open('http://localhost:{self.testSite.port}/simple_page_2', '_blank')",
- returnByValue=False, userGesture=True
+ # In Chrome 112 for some reason we can't specify useGesture and returnByValue at the same
+ # time, if we do we get an 'Object reference chain is too long' error.
+ # So don't use execute_javascript which insists on setting returnByValue.
+ self.devtools_client.execute(
+ "Runtime", "evaluate",
+ {
+ "expression": f"window.open('http://localhost:{self.testSite.port}/simple_page_2', '_blank')",
+ "userGesture": True
+ }
  )
 
  # Initially the title of the new tab is equal to the URL, but if we wait a bit it will

tests/unittests/chrome/test_interface.py

@@ -1,9 +1,9 @@
+import re
 from unittest import TestCase
-
 from unittest.mock import patch, MagicMock
 
 from browserdebuggertools.chrome.interface import ChromeInterface
-from browserdebuggertools.exceptions import TargetNotFoundError
+from browserdebuggertools.exceptions import TargetNotFoundError, JavascriptError
 
 MODULE_PATH = "browserdebuggertools.chrome.interface."
 
@@ -25,10 +25,54 @@ def test(self, mockExecute):
  result = self.interface.execute_javascript("document.readyState", foo="baa", x=2)
 
  mockExecute.assert_called_once_with(
- "Runtime", "evaluate", {"expression": "document.readyState", "foo": "baa", "x": 2}
+ "Runtime", "evaluate",
+ {
+ "expression": "document.readyState",
+ "foo": "baa", "x": 2, "returnByValue": True
+ }
  )
  self.assertEqual(mock_result, result)
 
+ def test_value_error(self, mockExecute):
+ mock_result = MagicMock()
+ mockExecute.return_value = {"id": 1, "result": {"value": mock_result}}
+
+ with self.assertRaisesRegex(
+ ValueError,
+ re.escape(
+ "If want returnByValue as False, "
+ "use .execute('runtime', 'evaluate', "
+ "{'expression': 'document.readyState', returnByValue: False}) directly"
+ )
+ ):
+ self.interface.execute_javascript(
+ "document.readyState", returnByValue=False
+ )
+
+ self.assertFalse(mockExecute.called)
+
+ def test_javascript_error(self, mockExecute):
+ mockExecute.return_value = {
+ "result": {
+ "type": "object",
+ "subtype": "error",
+ "className": "SyntaxError",
+ "description": "SyntaxError: Unexpected identifier 'and'",
+ "objectId": "1297274167796877720.2.1"
+ }
+ }
+
+ with self.assertRaises(JavascriptError):
+ self.interface.execute_javascript("garbage and stuff", foo="baa", x=2)
+
+ mockExecute.assert_called_once_with(
+ "Runtime", "evaluate",
+ {
+ "expression": "garbage and stuff",
+ "foo": "baa", "x": 2, "returnByValue": True
+ }
+ )
+
 
 class Test_ChromeInterface_switch_target(ChromeInterfaceTest):