On Mon, 30 Jun 2025 14:33:01 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 one additional > commit since the last revision: > > Review fixes; rewrite test to extend VisualTestBase tests/system/src/test/java/test/robot/javafx/stage/StageFocusTest.java line 118: > 116: Util.runAndWait(() -> { > 117: Color color = getColor(STAGE_SIZE / 2, STAGE_SIZE / 2); > 118: assertColorEquals(Color.LIGHTGREEN, color, TOLERANCE); I wonder if this implementation is a reliable test: the stage in question may be overlapped by another window somewhere in the corner, right? What would be a reliable test? Strictly speaking, we must check every pixel in the scene, though I wonder if checking each pixel in a grid (maybe 20 x 20, since we don't expect any reasonable window to be less than that) should be enough? ------------- PR Review Comment: https://git.openjdk.org/jfx/pull/1804#discussion_r2175524744
