Edge Browser freezes indefinitely when launching one Browser from another via a BrowserFunction #669

daniemur · 2023-05-12T20:13:00Z

Summary

Edge Browser freezes indefinitely when launching one Browser ("child" Browser) from another ("parent" Browser) via a BrowserFunction using Display#syncExec to create the child Browser. The same behavior is not exhibited when the child Browser is created within a Display#asyncExec call.

Also want to note when SWT gets into this waiting state, closing the window does not kill the process. The process will run until killed manually.

Code To Reproduce

package snippets;

import org.eclipse.swt.SWT;
import org.eclipse.swt.browser.Browser;
import org.eclipse.swt.browser.BrowserFunction;
import org.eclipse.swt.browser.ProgressAdapter;
import org.eclipse.swt.browser.ProgressEvent;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;

@SuppressWarnings({ "javadoc", "nls" })
public class EdgeSnippet
{
    private static Display display;
    private static Shell shell;

    public static void main(String[] args)
    {
        display = new Display();
        shell = new Shell(display);
        shell.setLayout(new FillLayout());

        Browser parentBrowser = new Browser(shell, SWT.EDGE);
        parentBrowser.setText("<!DOCTYPE html> \n"
                + "<html>\n"
                + "<head> \n"
                + "</head> \n"
                + "<body>\n"
                + "   <button onclick = \"openChildBrowser()\"> Open child browser </button> \n"
                + "   <p> \n"
                + "      <div id = \"result\"> </div> \n"
                + "   </p> \n"
                + "</body> \n"
                + "</html>");
        parentBrowser.addProgressListener(new ProgressAdapter()
        {
            @Override
            public void completed(ProgressEvent event)
            {
                new OpenChildBrowserBrowserFunction(parentBrowser, "openChildBrowser");
            }
        });

        shell.pack();
        shell.open();
        while (!shell.isDisposed())
        {
            if (!display.readAndDispatch())
            {
                display.sleep();
            }
        }
        display.dispose();
    }

    private static class OpenChildBrowserBrowserFunction extends BrowserFunction
    {
        public OpenChildBrowserBrowserFunction(Browser browser, String name)
        {
            super(browser, name);
        }

        @Override
        public Object function(Object[] arguments)
        {
            // If the following line is changed to asyncExec, the code executes just fine
            display.syncExec(() ->
            {
                System.out.println("Opening Child Shell");

                Shell childShell = new Shell(shell);
                childShell.setLayout(new FillLayout());
                childShell.setText("Child Browser");

                Browser childBrowser = new Browser(childShell, SWT.EDGE);
                childBrowser.setText("<!DOCTYPE html> \n"
                        + "<html>\n"
                        + "<head> \n"
                        + "</head> \n"
                        + "<body>\n"
                        + "   <p> \n"
                        + "      Child browser"
                        + "   </p> \n"
                        + "</body> \n"
                        + "</html>");

                childShell.pack();
                childShell.open();
            });
            return null;
        }
    }
}

Stack Trace

SWT waits indefinitely on the org.eclipse.swt.internal.win32.OS.WaitMessage call below:

org.eclipse.swt.internal.win32.OS.WaitMessage(Native Method)
org.eclipse.swt.widgets.Display.sleep(Display.java:4752)
org.eclipse.swt.browser.Edge.callAndWait(Edge.java:227)
org.eclipse.swt.browser.Edge.create(Edge.java:342)
org.eclipse.swt.browser.Browser.<init>(Browser.java:99)
snippets.EdgeSnippet$OpenChildBrowserBrowserFunction.lambda$0(EdgeSnippet.java:76)
org.eclipse.swt.widgets.Synchronizer.syncExec(Synchronizer.java:183)
org.eclipse.swt.widgets.Display.syncExec(Display.java:4785)
snippets.EdgeSnippet$OpenChildBrowserBrowserFunction.function(EdgeSnippet.java:68)
org.eclipse.swt.browser.Edge.handleCallJava(Edge.java:543)
org.eclipse.swt.internal.win32.OS.DispatchMessage(Native Method)
org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3640)
snippets.EdgeSnippet.main(EdgeSnippet.java:49)

Expected behavior
The child Browser opens successfully.

Environment:

Select the platform(s) on which the behavior is seen:

All OS
Windows
Linux
macOS

Additional OS info (e.g. OS version, Linux Desktop, etc)
Windows 10, also observed on Windows Server 2016
JRE/JDK version
JDK 11.0.14.1

Version since
SWT 3.117-Current (3.123 at the time of writing this)

Known Workarounds

Make either the parent, child, or both Browser(s) non-Edge Browser(s)
Use Display#asyncExec instead of Display#syncExec to create the child Browser

The text was updated successfully, but these errors were encountered:

HeikoKlare · 2023-05-15T11:25:54Z

The root cause for this behavior is that the WebView2 threading model does simply not allow this: https://learn.microsoft.com/en-us/microsoft-edge/webview2/concepts/threading-model
All handlers and callbacks are processed sequentially. Triggering another event from within a callback (as done in the example) leads to a deadlock.

A potential solution option is to execute whatever code is embedded into a callback in an asynchronous way. But since the current browser API is expected to operate synchronously and return results rather than futures, this may easily break compatibility.

At least the Edge browser implementation usually checks for these kinds of deadlocks and throws an exception rather than actually running into a deadlock:

eclipse.platform.swt/bundles/org.eclipse.swt/Eclipse SWT Browser/win32/org/eclipse/swt/browser/Edge.java

Lines 285 to 293 in 863dbe0

    
           void checkDeadlock() { 
        
           	// Feature in WebView2. All event handlers, completion handlers 
        
           	// and JavaScript callbacks are serialized. An event handler waiting 
        
           	// for a completion of another handler will deadlock. Detect this 
        
           	// situation and throw an exception instead. 
        
           	if (inCallback || inNewWindow) { 
        
           		SWT.error(SWT.ERROR_FAILED_EVALUATE, null, " [WebView2: deadlock detected]"); 
        
           	} 
        
           }

At this specific point (handleCallJava), the deadlock check is missing. This is something we may fix.

This contribution fixes Edge browser Deadlock issue on instantiating a new Edge Browser object during a webview callback using async execution. contributes to eclipse-platform#669

This contribution fixes Edge browser Deadlock issue on instantiating a new Edge Browser object during a webview callback using async execution. The Implementation follows the pattern similar to how WebKit has been implemented imitating the async behaviour in a sync fashion using Futures and callbacks. contributes to eclipse-platform#669

This contribution fixes Edge browser Deadlock issue on instantiating a new Edge Browser object during a webview callback using async execution. The Implementation follows the pattern similar to how WebKit has been implemented imitating the async behaviour in a sync fashion using Futures and callbacks. contributes to #669

amartya4256 · 2024-10-07T10:55:49Z

Fixed with #1378

akurtakov · 2024-10-07T11:26:27Z

Fixed with #1378

Did you mean to close it with this comment ?

This contribution fixes Edge browser Deadlock issue on instantiating a new Edge Browser object during a webview callback using async execution. The Implementation follows the pattern similar to how WebKit has been implemented imitating the async behaviour in a sync fashion using Futures and callbacks. contributes to eclipse-platform#669

This commit contributes to refactoring of all the ICoreWebView2* instances into a wrapper class WebViewWrapper for better encapsulation and fault proof initialization using a single future. Contributes to eclipse-platform#669

This commit contributes to refactoring of all the ICoreWebView2* instances into a wrapper class WebViewWrapper for better encapsulation and fault proof initialization using a single future. Contributes to #669

HeikoKlare added Windows Happens on Windows OS edge Edge Browser labels Jul 26, 2024

amartya4256 mentioned this issue Aug 8, 2024

Fix Edge Browser Deadlock issue for instantiation during a WebView Callback #1378

Merged

sratz mentioned this issue Sep 12, 2024

Edge: Roadmap to making edge the default browser on Windows #1466

Open

sratz closed this as completed Oct 7, 2024

sratz added this to the 4.34 M1 milestone Oct 7, 2024

HeikoKlare mentioned this issue Jan 27, 2025

[Win32] Summarize ICoreWebView2* instances in WebViewWrapper #1770

Merged

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Edge Browser freezes indefinitely when launching one Browser from another via a BrowserFunction #669

Edge Browser freezes indefinitely when launching one Browser from another via a BrowserFunction #669

daniemur commented May 12, 2023

HeikoKlare commented May 15, 2023

amartya4256 commented Oct 7, 2024

akurtakov commented Oct 7, 2024

Edge Browser freezes indefinitely when launching one Browser from another via a BrowserFunction #669

Edge Browser freezes indefinitely when launching one Browser from another via a BrowserFunction #669

Comments

daniemur commented May 12, 2023

Summary

Code To Reproduce

Stack Trace

HeikoKlare commented May 15, 2023

amartya4256 commented Oct 7, 2024

akurtakov commented Oct 7, 2024