[dotnet] Tolerate invalid UTF-16 strings in DevTools JSON response

dotnet/src/webdriver/DevTools/Json/DevToolsJsonOptions.cs

@@ -0,0 +1,18 @@
+using System.ComponentModel;
+using System.Text.Json;
+
+#nullable enable
+
+namespace OpenQA.Selenium.DevTools.Json;
+
+[EditorBrowsable(EditorBrowsableState.Never)] // Generated code use only
+internal static class DevToolsJsonOptions
+{
+    public static JsonSerializerOptions DevToolsSerializerOptions { get; } = new JsonSerializerOptions()
+    {
+        Converters =
+        {
+            new StringConverter(),
+        }
+    };
+}

dotnet/src/webdriver/DevTools/Json/StringConverter.cs

@@ -0,0 +1,35 @@
+using System;
+using System.Text;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+#nullable enable
+
+namespace OpenQA.Selenium.DevTools.Json;
+
+internal sealed class StringConverter : JsonConverter<string>
+{
+    public override bool HandleNull => true;
+
+    public override string? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+    {
+        try
+        {
+            return reader.GetString();
+        }
+        catch (InvalidOperationException)
+        {
+            // Backwards compatibility with Newtonsoft tolerating invalid UTF-16 sequences
+            // CDP sometimes sends invalid surrogate pairs on file upload
+
+            var bytes = reader.ValueSpan;
+            var sb = new StringBuilder(bytes.Length);
+            foreach (byte b in bytes)
+                sb.Append(Convert.ToChar(b));
+            return sb.ToString();
+        }
+    }
+
+    public override void Write(Utf8JsonWriter writer, string value, JsonSerializerOptions options) =>
+        writer.WriteStringValue(value);
+}

dotnet/src/webdriver/cdp/README.md

@@ -17,7 +17,7 @@ add an entry for version `<N>` to the `SupportedDevToolsVersions` dictionary ini
 6. In [`//dotnet/src/webdriver:WebDriver.csproj.prebuild.cmd`](https://github.com/SeleniumHQ/selenium/blob/trunk/dotnet/src/webdriver/WebDriver.csproj.prebuild.cmd),
 add the following block (substituting the proper value for `<N>`):
 
-```
+```bash
 if not exist  "%1..\..\..\bazel-bin\dotnet\src\webdriver\cdp\v<N>\DevToolsSessionDomains.cs" (
   echo Generating CDP code for version <N>
   pushd "%1..\..\.."
@@ -29,7 +29,7 @@ if not exist  "%1..\..\..\bazel-bin\dotnet\src\webdriver\cdp\v<N>\DevToolsSessio
 7. In [`//dotnet/src/webdriver:WebDriver.csproj.prebuild.sh`](https://github.com/SeleniumHQ/selenium/blob/trunk/dotnet/src/webdriver/WebDriver.csproj.prebuild.sh),
 add the following block (substituting the proper value for `<N>`):
 
-```
+```bash
 if [[ ! -f "$1../../../bazel-bin/dotnet/src/webdriver/cdp/v<N>/DevToolsSessionDomains.cs" ]]
 then
   echo "Generating CDP code for version <N>"

third_party/dotnet/devtools/src/generator/Templates/domain.hbs

@@ -61,7 +61,7 @@ namespace {{rootNamespace}}.{{domain.Name}}
                 if (m_eventMap.ContainsKey(e.EventName))
                 {
                     var eventData = m_eventMap[e.EventName];
-                    var eventArgs = e.EventData.Deserialize(eventData.EventArgsType);
+                    var eventArgs = e.EventData.Deserialize(eventData.EventArgsType, global::OpenQA.Selenium.DevTools.Json.DevToolsJsonOptions.DevToolsSerializerOptions);
                     eventData.EventInvoker(eventArgs);
                 }
             }