RFR: 8323664: java/awt/font/JNICheck/FreeTypeScalerJNICheck.java still fails with JNI warning on some Windows configurations [v2]
Christoph Langer
clanger at openjdk.org
Thu Jan 25 06:36:36 UTC 2024
> This picks up fixing the issue of [JDK-8276809](https://bugs.openjdk.org/browse/JDK-8276809) again. A fix had been integrated with #17224 but @prrace had concerns and so it was backed out.
>
> I have now spent quite some thoughts into the problem and end up with the [initial commit](https://github.com/openjdk/jdk/pull/6306/commits/5d18a76cb967e9ede6394cbd6c28bb61facf785c) of #6306 as the most elegant and least intrusive solution.
>
> Why is this?
>
> The JNI warning we observe in the test is:
> `[WARNING in native method: JNI call made without checking exceptions when required to from CallStaticVoidMethodV
> at sun.awt.Win32GraphicsEnvironment.initDisplay(java.desktop at 22.0.1-internal/Native Method)
> at sun.awt.Win32GraphicsEnvironment.initDisplayWrapper(java.desktop at 22.0.1-internal/Win32GraphicsEnvironment.java:95)
> at sun.awt.Win32GraphicsEnvironment.<clinit>(java.desktop at 22.0.1-internal/Win32GraphicsEnvironment.java:63)
> ...
> at FreeTypeScalerJNICheck.runTest(FreeTypeScalerJNICheck.java:53)
> at FreeTypeScalerJNICheck.main(FreeTypeScalerJNICheck.java:44)`
>
> This happens because obviously the test FreeTypeScalerJNICheck runs with `-Xcheck:jni` and in the scenario where we're observing the warning, a missing exception check for the JNI call to `sun.awt.Win32GraphicsEnvironment::dwmCompositionChanged` at awt_Win32GraphicsEnv.cpp#L129
> https://github.com/openjdk/jdk/blob/c5e72450966ad50d57a8d22e9d634bfcb319aee9/src/java.desktop/windows/native/libawt/windows/awt_Win32GraphicsEnv.cpp#L129 is airing up. Omitting the exception check would not be a problem if it could be guaranteed that after this call no other JNI->Java call was being made. But seemingly in this very particular configuration on some of our Windows servers, there must be JNI->Java calls that follow the call to `sun.awt.Win32GraphicsEnvironment::dwmCompositionChanged`, likely from the subsequent call to [initScreens](https://github.com/openjdk/jdk/blob/c5e72450966ad50d57a8d22e9d634bfcb319aee9/src/java.desktop/windows/native/libawt/windows/awt_Win32GraphicsEnv.cpp#L149) in `sun.awt.Win32GraphicsEnvironment::initDisplay`. https://github.com/openjdk/jdk/blob/8b6293f6bfb7b7628c6604e6c44401fc96d85cf4/src/java.desktop/windows/native/libawt/windows/awt_Win32GraphicsEnv.cpp#L141 Maybe the usual control flow would call the wrapping native method `DWMIsCompositi
onEnabled()` from somewhere else initially such that the initialization of `Win32GraphicsEnvironment` would not go through `initScreens` or similar.
> ...
Christoph Langer has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains four additional commits since the last revision:
- Changes to assertion function and test as discussed
- Revert "JDK-8323664"
This reverts commit 32128744252d75104e0d19f5eb701ffdc7b3d417.
- Merge branch 'master' into JDK-8323664
- JDK-8323664
-------------
Changes:
- all: https://git.openjdk.org/jdk/pull/17404/files
- new: https://git.openjdk.org/jdk/pull/17404/files/32128744..74e28e13
Webrevs:
- full: https://webrevs.openjdk.org/?repo=jdk&pr=17404&range=01
- incr: https://webrevs.openjdk.org/?repo=jdk&pr=17404&range=00-01
Stats: 16919 lines in 526 files changed: 8868 ins; 6037 del; 2014 mod
Patch: https://git.openjdk.org/jdk/pull/17404.diff
Fetch: git fetch https://git.openjdk.org/jdk.git pull/17404/head:pull/17404
PR: https://git.openjdk.org/jdk/pull/17404
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