On Fri, 4 Jul 2025 06:59:24 GMT, Lukasz Kostyra <lkost...@openjdk.org> wrote:
>> Originally this issue was supposed to resolve problems with some system >> tests (`MenuDoubleShortcutTest`, `TextAreaBehaviorTest` and others) failing >> on my Windows machine. In the process of figuring this out I found out the >> problem is Windows `::SetForegroundWindow()` API refusing to give focus to >> JFX Stage upon calling `Stage.show()`. >> >> The problem happened only when running system tests via Gradle, and with >> more investigation it turned out the culprit is actually running tests via a >> Gradle Daemon, which is the default behavior. According to >> [SetForegroundWindow API >> remarks](https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-setforegroundwindow) >> there is a list of conditions a process must meet to be granted a privilege >> of receiving focus, which is supposed to prevent focus stealing. While we do >> meet the required conditions, we don't meet "one of" additional conditions >> listed in the reference: >> - Gradle daemon is a background process, so tests started by it do not meet >> `The calling process is the foreground process.` and `The calling process >> was started by the foreground process.` conditions >> - We most probably run the tests from the terminal, so `There is currently >> no foreground window, and thus no foreground process.` condition fails - the >> foreground window is the Terminal itself. >> - Each test has fresh-started JFX stage so `The calling process received the >> last input event.` condition cannot be met and would require either Robot >> workarounds or manual interaction before each test case. >> - There is no debugger involved in the process (at least most of the time) >> so `Either the foreground process or the calling process is being debugged.` >> is also not met. >> >> As such, Windows refuses to grant JFX Stage focus, which fails some system >> tests relying on it. >> >> While we cannot remedy these conditions in-code (outside of hacky solutions >> I found with `AttachThreadInput` API which I am not a fan of) the only >> solution seems to be running the tests on Windows via either `gradle >> --no-daemon` or by setting `org.gradle.daemon=false` property somewhere in >> `gradle.properties`. >> >> In the process of debugging this problem I wrote a canary test to detect >> whether a Stage receives focus right after calling `show()`. I ran this test >> on all (accessible to me) platforms (Windows, Linux, macOS) - on both Linux >> and macOS the test passes regardless of whether the Gradle deamon is used or >> not. On my Windows machine (Win 11 24H2) it fails when testing... > > Lukasz Kostyra has updated the pull request incrementally with two additional > commits since the last revision: > > - Parameterize StageFocusTest > > This is to check if Stage showing works also for Stages other than the > primary Stage provided by Application.start() > - Review fixes; revert using VisualTestBase Code looks fine. I left a comment about providing a help message when the color sampling test fails. What does it mean to integrate this? We would be adding a test designed to fail with the default testing environment. After failure a developer would have to re-run with the no daemon flag set. Shouldn't that become the default? If not, can we ensure this test runs early so it truly serves as a canary test? Should folks developing new tests assume that they don't have to add the usual workarounds like sending a mouse click to the window? FWIW, adding the no daemon flag ensures that this test succeeds consistently with Cygwin. With the Mingw shell turning off the daemon increases the chance that it will succeed but doesn't guarantee it. tests/system/src/test/java/test/robot/javafx/stage/StageFocusTest.java line 204: > 202: // check if window is on top > 203: Util.runAndWait(() -> { > 204: WritableImage capture = robot.getScreenCapture(null, > STAGE_X, STAGE_Y, STAGE_SIZE, STAGE_SIZE, false); If the color test fails the developer doesn't see the helpful message telling them to use `--no-deamon` to patch things up. ------------- PR Review: https://git.openjdk.org/jfx/pull/1804#pullrequestreview-3017898964 PR Review Comment: https://git.openjdk.org/jfx/pull/1804#discussion_r2205867287
