[OpenJDK 2D-Dev] [14] Review request for 8227392: Colors with alpha are painted incorrectly on Linux, after JDK-8214579

Phil Race philip.race at oracle.com
Fri Jul 12 18:42:27 UTC 2019 

 > Would such a workaround be acceptable as part of this back out fix?

Yes, very much so !

-phil.

On 7/12/19 11:34 AM, Anton Litvinov wrote:
> Hello Phil,
>
> I tried to apply your code and can confirm that value of "color" is 
> always the same for the case, when the test passes and fails. For each 
> test run the "paint(Graphics)" method is called either 2 or 3 times 
> and this tracing output is always the same and following:
> "color=java.awt.Color[r=255,g=255,b=255] alpha=127"
>
> My today's experiments show that this intermittent failure is 
> reproducible with builds prior to the builds with the fix for 8214579 
> and this is also reproducible on Oracle Linux 7.4 x64. I was able to 
> reproduce in the following environment configurations:
>
> 1. Oracle Linux 7.4 x64 with JDK 13+23 (the build without the fix 
> 8214579 which was integrated in JDK 13+24)
> 2. openSUSE Leap 15.0 with JDK 13+23, JDK 11+25 (build in which the 
> test itself was introduced), JDK 11+28 (GA build).
>
> I attached a screenshot with the test failure and wrote a comment in 
> the bug (https://bugs.openjdk.java.net/browse/JDK-8224825).
>
> MY OBSERVATION:
>
> Although I have not been able to identify the root cause of the 
> intermittent test failure, I think that the wrong color is got, when 
> the black color, which is set as the background for the frame, is not 
> participating in color blending.
>
> THE DISCOVERED WORKAROUND:
>
> I discovered that if the following workaround is applied to the 
> regression test "test/jdk/java/awt/Color/AlphaColorTest.java", then 
> the intermittent test failure disappears (is not reproducible, when 
> test is run 20 times in a row). Also I verified with the workaround 
> the test fails as it should with JDK 11+24 (the build without the fix 
> 8204931 which was integrated in JDK 11+25 and introduced the test). 
> The workaround is following.
>
> Substitute the next 2 code lines:
>
> 77        frame = new Frame("Alpha Color Test");
> 78        frame.setBackground(Color.black);
>
> for the next 8 code lines:
>
>         frame = new Frame("Alpha Color Test") {
>             @Override
>             public void paint(Graphics g) {
>                 g.setColor(Color.black);
>                 g.fillRect(0, 0, getWidth(), getHeight());
>                 super.paint(g);
>             }
>         };
>
> Would such a workaround be acceptable as part of this back out fix?
>
> Thank you,
> Anton
>
> On 11/07/2019 19:48, Phil Race wrote:
>> I don't think we ever saw it fail until 8214579 was pushed.
>> I don't know the reason for the color you are sporadically getting in VB
>> Maybe it is slow and the paint event is being missed ?
>> But then I'd expect black .. not light grey.
>>
>> Still, it might be informative to put a print statement in here (in 
>> the test)
>>     public void paint(Graphics g) {
>>         System.out.println("color=" + color + " alpha=" + 
>> color.getAlpha());  // << add this
>>         g.setColor(color);
>>         g.fillRect(0, 0, getSize().width, getSize().height);
>>     }
>>
>> and compare what is printed for failing and passing runs.
>> If you can't figure it out quickly, then update the test to not exit 
>> so quickly and grab a screen
>> shot of the failure and add it to the bug.
>>
>>
>> -phil.
>>
>> On 7/11/19 11:13 AM, Anton Litvinov wrote:
>>> Hello Phil,
>>>
>>> Thank you for these additional details. I have tried to run the test 
>>> "open/test/jdk/java/awt/Color/AlphaColorTest.java" with JDK 13 
>>> compiled from "jdk/jdk13" with/without this back out fix and the 
>>> results are not so stable on my VirtualBox host with openSUSE Leap 
>>> 15.0 OS (GNOME 3.26.2):
>>>
>>> 1. "AlphaColorTest.java" stably fails with JDK 13 without this back 
>>> out fix and the test failure message is stably:
>>>     "Color is not as expected. Got java.awt.Color[r=255,g=255,b=255]"
>>>
>>> 2. "AlphaColorTest.java" starts passing with JDK 13 with the back 
>>> out fix, but continues to intermittently fail with the failure message:
>>>     "Color is not as expected. Got java.awt.Color[r=189,g=189,b=189]"
>>>
>>> It looks that either this regression test had been failing 
>>> intermittently before the fix 8214579, which we are backing out, was 
>>> integrated, or some other fix causes this intermittent failure.
>>>
>>> Maybe in this case it is better not to change this 
>>> "open/test/jdk/ProblemList.txt" as well as the test itself 
>>> "open/test/jdk/java/awt/Color/AlphaColorTest.java" as part of this 
>>> back out fix for JCK test failure?
>>>
>>> Thank you,
>>> Anton
>>>
>>> On 11/07/2019 17:38, Philip Race wrote:
>>>> There is a regression test that is supposed to catch this exact 
>>>> problem.
>>>>
>>>> So I had looked into how we did not catch this earlier and found 
>>>> that in fact we did.
>>>> This was originally found and filed as 
>>>> https://bugs.openjdk.java.net/browse/JDK-8224825
>>>> The test java/awt/Color/AlphaColorTest.java was then problem listed 
>>>> on Linux.
>>>>
>>>> $ grep AlphaColorTest test/jdk/ProblemList.txt
>>>> java/awt/Color/AlphaColorTest.java 8224825 linux-all
>>>>
>>>> So I think we can close JDK-8224825 as a duplicate of this as well 
>>>> as updating the problem list
>>>> and the test - after confirming that this backout resolves that as 
>>>> I expect it will.
>>>>
>>>> -phil.
>>>>
>>>> On 7/11/19, 9:20 AM, Anton Litvinov wrote:
>>>>> By your request regenerated the webrev specifically against 
>>>>> (http://hg.openjdk.java.net/jdk/jdk13) repository.
>>>>> JDK 13 specific webrev: 
>>>>> http://cr.openjdk.java.net/~alitvinov/8227392/jdk13/webrev.00
>>>>>
>>>>> I confirm again, that 2 failing manual tests: "ColorTest0003", 
>>>>> "ColorTest0004" from the test 
>>>>> "api/java_awt/interactive/ColorTests.html" in JCK 13 do not fail 
>>>>> anymore after this fix is applied to JDK 13 compiled from 
>>>>> "jdk/jdk13" repository.
>>>>>
>>>>> "jdk/jdk13" repository does not contain any problem list 
>>>>> mentioning "api/java_awt/interactive/ColorTests.html" test from 
>>>>> JCK 13, thus I cannot de-problem list it and have no idea, where 
>>>>> it is problem-listed. I also doubt that it is problem-listed, 
>>>>> since it is manual. I added "noreg-jck" label to the bug in JBS 
>>>>> deliberately according to OpenJDK process (Section #6 from the web 
>>>>> page (http://openjdk.java.net/guide/changePlanning.html)), because 
>>>>> this back out fix does not contain a new separate regression test, 
>>>>> while this regression can be checked by running existing mentioned 
>>>>> above test from JCK package.
>>>>>
>>>>> If this "noreg-jck" label creates problems, I can remove it at all.
>>>>>
>>>>> Thank you,
>>>>> Anton
>>>>>
>>>>> On 11/07/2019 15:51, Philip Race wrote:
>>>>>> One more thing I just realised you should do here is de-problem list
>>>>>> the regression test that fails ... after verifying it now works,
>>>>>> updating it with this bug ID.
>>>>>> And you can remove that noreg-jck label as a consequence.
>>>>>>
>>>>>> -phil.
>>>>>>
>>>>>> On 7/11/19, 7:35 AM, Philip Race wrote:
>>>>>>> In such cases I like more than to be told "it would apply 
>>>>>>> cleanly" but also to see
>>>>>>> that you actually prepared the webrev against 13. This is more 
>>>>>>> certain
>>>>>>> and ensures that when the fix is approved you don't accidentally 
>>>>>>> push it
>>>>>>> to the wrong repo. You have to go clone 13 and apply the patch 
>>>>>>> there anyway ...
>>>>>>>
>>>>>>> -phil.
>>>>>>>
>>>>>>> On 7/11/19, 5:44 AM, Anton Litvinov wrote:
>>>>>>>> Hello Phil,
>>>>>>>>
>>>>>>>> Thank you for review and the important remark about the need to 
>>>>>>>> work with "jdk/jdk13" stabilization repository, I forgot about 
>>>>>>>> this feature of post RDP 1 phase. Today I checked the fix 
>>>>>>>> against "jdk/jdk13" repository and confirm that it resolves 
>>>>>>>> this bug for JDK 13.
>>>>>>>>
>>>>>>>> Will wait for feedback or approval from any other second code 
>>>>>>>> reviewer.
>>>>>>>>
>>>>>>>> Thank you,
>>>>>>>> Anton
>>>>>>>>
>>>>>>>> On 10/07/2019 19:55, Phil Race wrote:
>>>>>>>>> Anton,
>>>>>>>>>
>>>>>>>>> This looks fine except that it needs to be prepared against 
>>>>>>>>> 13, and then pushed there, not 14.
>>>>>>>>> And it will get forwarded synced from 13 to 14. That is the 
>>>>>>>>> RDP process ..
>>>>>>>>>
>>>>>>>>> -phil.
>>>>>>>>>
>>>>>>>>> On 7/10/19 5:00 AM, Anton Litvinov wrote:
>>>>>>>>>> Hello,
>>>>>>>>>>
>>>>>>>>>> Could you please review the following fix for the bug. The 
>>>>>>>>>> fix is backing out of the fix for the bug JDK-8214579 which 
>>>>>>>>>> caused this JCK test failure. If this fix is accepted, then a 
>>>>>>>>>> new separate bug for readdressing the bug reported in 
>>>>>>>>>> JDK-8214579 will be filed.
>>>>>>>>>>
>>>>>>>>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8227392
>>>>>>>>>> Webrev: 
>>>>>>>>>> http://cr.openjdk.java.net/~alitvinov/8227392/jdk14/webrev.00
>>>>>>>>>> Changeset of JDK-8214579: 
>>>>>>>>>> http://hg.openjdk.java.net/jdk/client/rev/c53905e7dc57
>>>>>>>>>>
>>>>>>>>>> Thank you,
>>>>>>>>>> Anton
>>>>>>>>>
>>>>>>>>
>>>>>
>>>
>>
>

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