Test_org_eclipse_swt_browser_Browser.test_BrowserFunction_availableOnLoad_concurrentInstances_issue20 failed on Win32 in I20260418-1800

[trancexpress]

See: https://download.eclipse.org/eclipse/downloads/drops4/I20260418-1800/testresults/html/org.eclipse.swt.tests_ep440I-unit-win32-x86_64-java21_win32.win32.x86_64_21.html

	BrowserFunction must be available when page load completes on both browsers (regression of https://github.com/eclipse-platform/eclipse.platform.swt/issues/20) ==> expected: <true> but was: <false>

org.opentest4j.AssertionFailedError: BrowserFunction must be available when page load completes on both browsers (regression of https://github.com/eclipse-platform/eclipse.platform.swt/issues/20) ==> expected: <true> but was: <false>
at org.junit.jupiter.api.AssertionFailureBuilder.build(AssertionFailureBuilder.java:151)
at org.junit.jupiter.api.AssertionFailureBuilder.buildAndThrow(AssertionFailureBuilder.java:132)
at org.junit.jupiter.api.AssertTrue.failNotTrue(AssertTrue.java:63)
at org.junit.jupiter.api.AssertTrue.assertTrue(AssertTrue.java:36)
at org.junit.jupiter.api.Assertions.assertTrue(Assertions.java:214)
at org.eclipse.swt.tests.junit.Test_org_eclipse_swt_browser_Browser.test_BrowserFunction_availableOnLoad_concurrentInstances_issue20(Test_org_eclipse_swt_browser_Browser.java:3029)
at java.base/java.lang.reflect.Method.invoke(Method.java:580)
at java.base/java.util.ArrayList.forEach(ArrayList.java:1596)
at java.base/java.util.ArrayList.forEach(ArrayList.java:1596)
Suppressed: java.lang.RuntimeException: AwtScreenshot VM finished with exit code 1:
Exception in thread "main" java.awt.AWTError: no screen devices
at java.desktop/sun.awt.Win32GraphicsEnvironment.getDefaultScreenDevice(Win32GraphicsEnvironment.java:101)
at java.desktop/java.awt.Robot.<init>(Robot.java:135)
at org.eclipse.test.AwtScreenshot.main(AwtScreenshot.java:43)

at org.eclipse.test.AwtScreenshot.dumpAwtScreenshot(AwtScreenshot.java:113)
at org.eclipse.test.Screenshots.takeScreenshot(Screenshots.java:102)
at org.eclipse.swt.tests.junit.Test_org_eclipse_swt_widgets_Widget.lambda$1(Test_org_eclipse_swt_widgets_Widget.java:79)
at java.base/java.util.Optional.ifPresent(Optional.java:178)
at org.eclipse.swt.tests.junit.Test_org_eclipse_swt_widgets_Widget.lambda$0(Test_org_eclipse_swt_widgets_Widget.java:75)
... 2 more 

Test seems to be added with: c312bcf

For: #20

[trancexpress]

@HeikoKlare it seems that one of the new tests is failing.

[HeikoKlare]

I derived the following assessment in an analysis session with Claude.

Root Cause

The test calls addProgressListener after new BrowserFunction, but new BrowserFunction internally pumps the event loop via processOSMessagesUntil inside registerFunctionScript (through getWebView(true)).

getWebView(true) waits for lastWebViewTask::isDone, which includes the Navigate task scheduled by the preceding b1.setUrl("about:blank") call. Waiting for this task requires pumping the event loop long enough that the NavigationCompleted event for about:blank can fire during the pump — before addProgressListener has been registered. The event is dispatched and lost, no further NavigationCompleted fires, and browser1FuncAvailable is never set, causing the test to time out.

The concurrent second browser (b2) increases the probability of this happening by causing additional event loop processing during initialization.

The asyncExec deferral introduced in createFunction does not help here because it only triggers when createFunction is called from inside a WebView2 callback (inCallback > 0). In this test, new BrowserFunction is called from regular Java code, so inCallback == 0 and registerFunctionScript is called synchronously.

Fix

Change getWebView(true) to getWebView(false) in registerFunctionScript. This limits the event loop pump to only waiting for WebView2 initialization (webViewWrapperFuture::isDone) rather than also waiting for pending navigation tasks. Since the Navigate call is chained on the ForkJoinPool after initialization completes, it cannot have fired yet when getWebView(false) returns, and NavigationCompleted therefore cannot fire during registerFunctionScript. By the time it eventually fires, addProgressListener is already registered and the test passes correctly.

The current document is not a concern: super.createFunction() already covers it via nonBlockingExecute(function.functionString) before registerFunctionScript is even entered.

[HeikoKlare]

Failure is sporadic. It did not occur in today's I-Build tests. But it happened in #3256 with a more specific error message, which shows that on evaluation of the progress completed listener of the first browser in the test, the browser function has not been registered yet:

options is not defined
org.eclipse.swt.SWTException: options is not defined
	at org.eclipse.swt.browser.Edge.evaluateInternal(Edge.java:1003)
	at org.eclipse.swt.browser.Edge.evaluate(Edge.java:976)
	at org.eclipse.swt.browser.WebBrowser.evaluate(WebBrowser.java:405)
	at org.eclipse.swt.browser.Browser.evaluate(Browser.java:735)
	at org.eclipse.swt.browser.Browser.evaluate(Browser.java:684)
	at org.eclipse.swt.tests.junit.Test_org_eclipse_swt_browser_Browser.lambda$156(Test_org_eclipse_swt_browser_Browser.java:3008)
	at org.eclipse.swt.browser.ProgressListener$2.completed(ProgressListener.java:97)
	at org.eclipse.swt.browser.Edge.lambda$44(Edge.java:1218)
	at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:40)
	at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:131)
	at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:4136)
	at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3752)
	at org.eclipse.swt.tests.junit.Test_org_eclipse_swt_browser_Browser.waitForPassCondition(Test_org_eclipse_swt_browser_Browser.java:3139)
	at org.eclipse.swt.tests.junit.Test_org_eclipse_swt_browser_Browser.waitForPassCondition(Test_org_eclipse_swt_browser_Browser.java:3105)
	at org.eclipse.swt.tests.junit.Test_org_eclipse_swt_browser_Browser.test_BrowserFunction_availableOnLoad_concurrentInstances_issue20(Test_org_eclipse_swt_browser_Browser.java:3035)