RFR 8181299/10, Several jdk tests fail with java.lang.NoClassDefFoundError: jdk/test/lib/process/StreamPumper

[Igor Ignatyev]

Hi Felix,

none of the jdk tests which fail w/ NCDFE: jdk/test/lib/process/StreamPumper depend on StreamPumper directly, they get this dependency transitively from jdk/test/lib/process/ProcessTools, so I don't see how you will find this good definition of "explicit" even for the failures at hand.

I recommend to work around this the same way we did it in hotspot, which reliably removed almost all our NCDFE failures, -- remove explicit @build, if not all for all classes, then at least for jdk/test/lib/** classes.

-- Igor

> On Jun 1, 2017, at 6:52 PM, Felix Yang <felix.yang at oracle.com> wrote:
> 
> Hi Igor and Ioi,
> 
>      I partially agree with you. As initially stated in the proposal and bug(JDK-8181299 <https://bugs.openjdk.java.net/browse/JDK-8181299>), I don't think this patch is a fix but a quick workaround to make them runnable.
> 
>     "explicit" is reasonable for me. But "explicit" should not be restricted as "explicit all, including dependencies", as it is not productive or even realistic in the long term.
> Thanks,
> Felix
> On 2017/6/2 7:58, Igor Ignatyev wrote:
>>> For example: doing this may be enough for now:
>>> 
>>>     * @build jdk.test.lib.process.*
>>> 
>>> But what if in the future, jdk.test.lib.process is restructured to have a private package jdk.test.lib.process.hidden? To work around CODETOOLS-7901986, all the test cases that must be modified to the following, which unnecessarily exposes library implementation details to the library users:
>>> 
>>>     * @build jdk.test.lib.process.* jdk.test.lib.process.hidden.*
>> 
>> and in fact, there is already similar problem and http://cr.openjdk.java.net/~xiaofeya/8181299/webrev.01/ <http://cr.openjdk.java.net/%7Exiaofeya/8181299/webrev.01/> does not address it.
>> jdk/test/lib/process/ProcessTools depends on jdk/test/lib/Utils so all tests which have '@build jdk.test.lib.process.ProcessTools' will have to have  '@build jdk.test.lib.Utils'. then we have OutputAnalyzer which depends on ProcessTools so all tests which @build jdk.test.lib.process.OutputAnalyzer will @build ProcessTools and Utils explicitly.  many testlibrary classes which on jdk.test.lib.process.OutputAnalyzer, so one will have to specify OutputAnalyzer ProcessTools and Utils in the tests which depends on other testlibrary classes.  to make things even worse, Utils depends on OutputAnalyzer and there are lots of tests and test library classes which depend on Utils, so all of them will have to have at least '@build jdk.test.lib.Utils jdk.test.lib.process.OutputAnalyzer jdk.test.lib.process.ProcessTools'. and they will work stable till someone refactors them and extract some new classes. that is to say, it's nearly impossible to have all explicit @build actions.
>> 
>> Cheers,
>> -- Igor
>> 
>>> On Jun 1, 2017, at 3:37 PM, Ioi Lam <ioi.lam at oracle.com <mailto:ioi.lam at oracle.com>> wrote:
>>> 
>>> 
>>> 
>>> On 6/1/17 1:17 PM, Igor Ignatyev wrote:
>>>>> On Jun 1, 2017, at 1:20 AM, Chris Hegarty <chris.hegarty at oracle.com <mailto:chris.hegarty at oracle.com>> wrote:
>>>>> 
>>>>> Igor,
>>>>> 
>>>>>> On 1 Jun 2017, at 04:32, Igor Ignatyev <igor.ignatyev at oracle.com <mailto:igor.ignatyev at oracle.com>> wrote:
>>>>>> 
>>>>>> Hi Felix,
>>>>>> 
>>>>>> I have suggested the exact opposite change[1-3] to fix the same problem.
>>>>> I’m sorry, but this is all just too confusing. After your change, who, or what, is
>>>>> responsible for building/compiling the test library dependencies?
>>>> jtreg is responsible, there is an implicit build for each @run, and jtreg will analyze a test class to get transitive closure for static dependencies, hence you have to have @build only for classes which are not in constant pool, e.g. used only by reflection or whose classnames are only used to spawn a new java instance.
>>> 
>>> 
>>> I suspect the problem is caused by a long standing bug in jtreg that results in library classes being partially compiled. Please see my evaluation in
>>> 
>>> https://bugs.openjdk.java.net/browse/CODETOOLS-7901986 <https://bugs.openjdk.java.net/browse/CODETOOLS-7901986>
>>> 
>>> In the bug report, there is test case that can reliably reproduce the NoClassDefFoundError problem.
>>> 
>>> I think adding all the @build commands in the tests are just band-aids. Things will break unless every test explicitly uses @build to build every class in every library that they use, including all the private classes that are not directly accessible by the test cases.
>>> 
>>> For example: doing this may be enough for now:
>>> 
>>>     * @build jdk.test.lib.process.*
>>> 
>>> But what if in the future, jdk.test.lib.process is restructured to have a private package jdk.test.lib.process.hidden? To work around CODETOOLS-7901986, all the test cases that must be modified to the following, which unnecessarily exposes library implementation details to the library users:
>>> 
>>>     * @build jdk.test.lib.process.* jdk.test.lib.process.hidden.*
>>> 
>>> Just imagine this -- "in order to use malloc() you must explicitly build not only malloc(), but also sbrk() ... and every other function in libc". That seems unreasonable to me.
>>> 
>>> By the way, we made a fix in the HotSpot tests (see https://bugs.openjdk.java.net/browse/JDK-8157957 <https://bugs.openjdk.java.net/browse/JDK-8157957>) that got rid of many (but not all) of the NoClassDefFoundErrors by *removing* the @build lines .....
>>> 
>>> My proposal is, instead of just adding @build for band-aid, we should fix CODETOOLS-7901986 instead.
>>> 
>>> Thanks
>>> - Ioi
>>> 
>>> 
>>>>> 
>>>>> Test library code has no @modules tags, so does not explicitly declare its
>>>>> module dependencies. Instead module dependencies, required by test
>>>>> library code, are declared in the test using the library. If we wildcard, or
>>>>> otherwise leave broad build dependencies, from tests then there is no
>>>>> way to know what new module dependencies may be added in the future.
>>>>> That is, one of, the reason(s) I asked Felix to be explicit about the build
>>>>> dependencies.
>>>> having explicit builds does not really help w/ module dependency, if someone change a testlibrary class so it starts to depend on another testlibrary class, jtreg will implicitly build it and if this class has some module dependencies, you will have to reflect them in the test.
>>>> 
>>>> generally speaking, I don't like having explicit build actions because build actions themselves are implicit, so they don't really help, it's still will be hard to spot missed explicit builds. not having (unneeded) explicit builds is an easy rule to follow and we can easily find all places which don't follow this rule by grep.
>>>> 
>>>> -- Igor
>>>>> -Chris.
>>>>> 
>>>>>> [1] https://bugs.openjdk.java.net/browse/JDK-8181391 <https://bugs.openjdk.java.net/browse/JDK-8181391>
>>>>>> [2] http://mail.openjdk.java.net/pipermail/core-libs-dev/2017-June/048012.html <http://mail.openjdk.java.net/pipermail/core-libs-dev/2017-June/048012.html>
>>>>>> [3] http://cr.openjdk.java.net/~iignatyev//8181391/webrev.00/index.html <http://cr.openjdk.java.net/%7Eiignatyev//8181391/webrev.00/index.html>
> 

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