Bug 1780752 - [bidi] Handle exception objects which don't support toS…

…tring r=webdriver-reviewers,jgraham

Differential Revision: https://phabricator.services.mozilla.com/D152506

remote/webdriver-bidi/RemoteValue.jsm

@@ -4,7 +4,7 @@
 
 "use strict";
 
-var EXPORTED_SYMBOLS = ["deserialize", "serialize"];
+var EXPORTED_SYMBOLS = ["deserialize", "serialize", "stringify"];
 
 const { XPCOMUtils } = ChromeUtils.importESModule(
   "resource://gre/modules/XPCOMUtils.sys.mjs"
@@ -418,8 +418,32 @@ function serialize(
   }
 
   lazy.logger.warn(
-    `Unsupported type: ${type} for remote value: ${value.toString()}`
+    `Unsupported type: ${type} for remote value: ${stringify(value)}`
   );
 
   return undefined;
 }
+
+/**
+ * Safely stringify a value.
+ *
+ * @param {Object} value
+ *     Value of any type to be stringified.
+ *
+ * @returns {String} String representation of the value.
+ */
+function stringify(obj) {
+  let text;
+  try {
+    text =
+      obj !== null && typeof obj === "object" ? obj.toString() : String(obj);
+  } catch (e) {
+    // The error-case will also be handled in `finally {}`.
+  } finally {
+    if (typeof text != "string") {
+      text = Object.prototype.toString.apply(obj);
+    }
+  }
+
+  return text;
+}

remote/webdriver-bidi/modules/windowglobal/script.jsm

@@ -23,6 +23,7 @@ XPCOMUtils.defineLazyModuleGetters(lazy, {
   getFramesFromStack: "chrome://remote/content/shared/Stack.jsm",
   isChromeFrame: "chrome://remote/content/shared/Stack.jsm",
   serialize: "chrome://remote/content/webdriver-bidi/RemoteValue.jsm",
+  stringify: "chrome://remote/content/webdriver-bidi/RemoteValue.jsm",
 });
 
 XPCOMUtils.defineLazyGetter(lazy, "dbg", () => {
@@ -88,10 +89,7 @@ class ScriptModule extends Module {
       exception: lazy.serialize(exception, 1),
       lineNumber: stack.line - 1,
       stackTrace: { callFrames },
-      text:
-        typeof exception === "object"
-          ? exception.toString()
-          : String(exception),
+      text: lazy.stringify(exception),
     };
   }
 

remote/webdriver-bidi/test/xpcshell/test_RemoteValue.js

@@ -223,7 +223,7 @@ const REMOTE_COMPLEX_VALUES = [
   },
 ];
 
-const { deserialize, serialize } = ChromeUtils.import(
+const { deserialize, serialize, stringify } = ChromeUtils.import(
   "chrome://remote/content/webdriver-bidi/RemoteValue.jsm"
 );
 
@@ -557,3 +557,41 @@ add_test(function test_serializeRemoteComplexValues() {
 
   run_next_test();
 });
+
+add_test(function test_stringify() {
+  const STRINGIFY_TEST_CASES = [
+    [undefined, "undefined"],
+    [null, "null"],
+    ["foobar", "foobar"],
+    ["2", "2"],
+    [-0, "0"],
+    [Infinity, "Infinity"],
+    [-Infinity, "-Infinity"],
+    [3, "3"],
+    [1.4, "1.4"],
+    [true, "true"],
+    [42n, "42"],
+    [{ toString: () => "bar" }, "bar", "toString: () => 'bar'"],
+    [{ toString: () => 4 }, "[object Object]", "toString: () => 4"],
+    [{ toString: undefined }, "[object Object]", "toString: undefined"],
+    [{ toString: null }, "[object Object]", "toString: null"],
+    [
+      {
+        toString: () => {
+          throw new Error("toString error");
+        },
+      },
+      "[object Object]",
+      "toString: () => { throw new Error('toString error'); }",
+    ],
+  ];
+
+  for (const [value, expectedString, description] of STRINGIFY_TEST_CASES) {
+    info(`Checking '${description || value}'`);
+    const stringifiedValue = stringify(value);
+
+    Assert.strictEqual(expectedString, stringifiedValue, "Got expected string");
+  }
+
+  run_next_test();
+});

testing/web-platform/mozilla/tests/webdriver/bidi/script/exception_details.py

@@ -0,0 +1,70 @@
+import pytest
+
+from webdriver.bidi.modules.script import ContextTarget, ScriptEvaluateResultException
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize("await_promise", [True, False])
+@pytest.mark.parametrize(
+    "expression",
+    [
+        "null",
+        "{ toString: 'not a function' }",
+        "{ toString: () => {{ throw 'toString not allowed'; }} }",
+        "{ toString: () => true }",
+    ],
+)
+@pytest.mark.asyncio
+async def test_call_function_without_to_string_interface(
+    bidi_session, top_context, await_promise, expression
+):
+    function_declaration = "()=>{throw { toString: 'not a function' } }"
+    if await_promise:
+        function_declaration = "async" + function_declaration
+
+    with pytest.raises(ScriptEvaluateResultException) as exception:
+        await bidi_session.script.call_function(
+            function_declaration=function_declaration,
+            await_promise=await_promise,
+            target=ContextTarget(top_context["context"]),
+        )
+
+    assert "exceptionDetails" in exception.value.result
+    exceptionDetails = exception.value.result["exceptionDetails"]
+
+    assert "text" in exceptionDetails
+    assert isinstance(exceptionDetails["text"], str)
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize("await_promise", [True, False])
+@pytest.mark.parametrize(
+    "expression",
+    [
+        "null",
+        "{ toString: 'not a function' }",
+        "{ toString: () => {{ throw 'toString not allowed'; }} }",
+        "{ toString: () => true }",
+    ],
+)
+@pytest.mark.asyncio
+async def test_evaluate_without_to_string_interface(
+    bidi_session, top_context, await_promise, expression
+):
+    if await_promise:
+        expression = f"Promise.reject({expression})"
+    else:
+        expression = f"throw {expression}"
+
+    with pytest.raises(ScriptEvaluateResultException) as exception:
+        await bidi_session.script.evaluate(
+            expression=expression,
+            await_promise=await_promise,
+            target=ContextTarget(top_context["context"]),
+        )
+
+    assert "exceptionDetails" in exception.value.result
+    exceptionDetails = exception.value.result["exceptionDetails"]
+
+    assert "text" in exceptionDetails
+    assert isinstance(exceptionDetails["text"], str)

testing/web-platform/tests/webdriver/tests/bidi/conftest.py

@@ -34,9 +34,3 @@ def test_page_cross_origin_frame(inline, test_page_cross_origin):
 @pytest.fixture
 def test_page_same_origin_frame(inline, test_page):
     return inline(f"<iframe src='{test_page}'></iframe>")
-
-
-@pytest.fixture
-async def top_context(bidi_session):
-    contexts = await bidi_session.browsing_context.get_tree()
-    return contexts[0]

testing/web-platform/tests/webdriver/tests/support/fixtures.py

@@ -248,3 +248,9 @@ def iframe(src, **kwargs):
         return "<iframe src='{}'></iframe>".format(inline(src, **kwargs))
 
     return iframe
+
+
+@pytest.fixture
+async def top_context(bidi_session):
+    contexts = await bidi_session.browsing_context.get_tree()
+    return contexts[0]