macOS: don't crash the process when bridge injection fails on a non-s… - #82
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…criptable navigation OnDelegateOnDidFinishNavigation unconditionally injects the C#<->JS bridge script via InvokeScript on every finished navigation. When the navigation loaded non-HTML content (e.g. a file/PDF/image download response), WKWebView.evaluateJavaScript fails at the native WebKit level; InvokeScript already converts that into a JavaScriptException, but nothing caught it in this async void handler, so the exception escaped and crashed the whole process instead of just failing that one bridge-injection attempt. Reproduced consistently on macOS (Apple Silicon) with a ChatGPT-generated file download: clicking the download link crashed the process every time, with the app otherwise working correctly (login, session persistence, drag-and-drop upload, and clipboard paste all unaffected). Fix: wrap the InvokeScript call in a try/catch for JavaScriptException. This only stops the crash - it does not add file-download handling (saving, progress, etc.), which is a separate, larger change (decidePolicyForNavigationResponse + WKDownloadDelegate) intentionally left out of this PR; happy to open that as its own follow-up if there's interest. Verified by building this change locally (net8.0 and net10.0 desktop TFMs) and by running AtprismPoc, an Avalonia app that embeds NativeWebView, against a ProjectReference to this patched clone: the same download that reliably crashed the process before no longer does.
maxkatz6
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Sep 2, 2026
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| // The just-finished navigation didn't load a scriptable HTML document (e.g. a file | ||
| // download, image, or PDF response) - EvaluateJavaScriptAsync then fails at the |
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We should try to detect common document types on which script cannot be executed.
And log error/warning when this "script invoke" failed. There might be situations, when this script call is expected, but exception would be silently ignored after this PR.
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Also please write a more concise code comment, with more natural line breaks.
The longer comment the less people will actually read it in the future.
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…criptable navigation
OnDelegateOnDidFinishNavigation unconditionally injects the C#<->JS bridge script via InvokeScript on every finished navigation. When the navigation loaded non-HTML content (e.g. a file/PDF/image download response), WKWebView.evaluateJavaScript fails at the native WebKit level; InvokeScript already converts that into a JavaScriptException, but nothing caught it in this async void handler, so the exception escaped and crashed the whole process instead of just failing that one bridge-injection attempt.
Reproduced consistently on macOS (Apple Silicon) with a ChatGPT-generated file download: clicking the download link crashed the process every time, with the app otherwise working correctly (login, session persistence, drag-and-drop upload, and clipboard paste all unaffected).
Fix: wrap the InvokeScript call in a try/catch for JavaScriptException. This only stops the crash - it does not add file-download handling (saving, progress, etc.), which is a separate, larger change (decidePolicyForNavigationResponse
Verified by building this change locally (net8.0 and net10.0 desktop TFMs) and by running AtprismPoc, an Avalonia app that embeds NativeWebView, against a ProjectReference to this patched clone: the same download that reliably crashed the process before no longer does.