Memory leak when data isn't read in WebMessageReceived

[avendel]

Description

When the top-level document of the WebView runs window.chrome.webview.postMessage, and no code in the host process reads the message data, memory is allocated but never released.

Version
SDK: 1.0.2045.28
Runtime: 117.0.2045.31
Framework: WinForms, .NET Framework 4.8.1
OS: Win11

Regression
Don't know whether this is a regression.

Repro Steps

The fastest way of seeing this behavior is to call postMessage with a large data object, like in the example below.

<script lang="javascript">
    function sendMessageToHost() {
        window.chrome.webview.postMessage(new Array(90000));
    }

    setInterval(sendMessageToHost, 100);
</script>

Then in the hosting .NET code, either don't add an event handler for CoreWebView2.WebMessageReceived, or don't read the message json.

this.webView.NavigateToString(html);
this.webView.CoreWebView2.WebMessageReceived += (sender, e) => {
    // Without executing the line below, memory is allocated but never released.
    //this.LastMessage = e.WebMessageAsJson;
};

The host process leaks unmanaged memory.

AB#46620265

[yildirimcagri-msft]

Thanks for reporting this, we have a fix in the works.

[yildirimcagri-msft]

The fix will be available in the next SDK release. Thanks again!