RFR(S) : 8180805 : move RandomFactory to the top level testlibrary

[Jonathan Gibbons]

You cannot completely disable implicit compilation as a concept, because 
it is built into javac, and has been since Day One.

But we could reduce its impact.

javac does have an option -implicit:none, which stops it *writing* 
implicitly compiled classes, (but not stop it reading them). So the 
compilation will succeed, but the runtime may fail, because some 
necessary classes may not have been written.  We may be able to test 
(play) with that idea by using the jtreg option "-javacoption:<option>"

We could reduce the chance of it reading source files it might want to 
implicitly compile by reducing what goes on the source path. That would 
require changes to jtreg.

It should be easy enough to write scripts to run tests one at a time and 
test for implicitly compiled classes, or you could try the approach I 
suggested earlier and run blocks of tests and look for duplicate class 
files, as an indication of implicit compilation.

-- Jon

On 06/05/2017 03:50 PM, Igor Ignatyev wrote:
> Hi Jon,
>
> if tests are supposed to declare all library classes they depend on, tests start to depend on a library design, so refactoring of the library will force us to do massive update of the tests to fix their explicit builds, but to find all such tests, we will have to run them one by one. so this approach does not really scale and it is also kinda fragile.
> if we can not relay on implicit compilation done by @build (and implicit @build) actions, shouldn't we remove it completely? or at least introduce a jtreg flag which disables it or reports all such usage as errors? this will give us a way to find all tests to fix and eventually will make the whole testsuite more reliable.
>
> -- Igor
>   
>> On Jun 5, 2017, at 3:39 PM, Jonathan Gibbons <jonathan.gibbons at oracle.com> wrote:
>>
>>
>>
>> On 06/05/2017 03:24 PM, Martin Buchholz wrote:
>>> Can we find missing @build directives by running each individual jtreg test by itself with a clean JTwork directory?
>> That's generally been the recommended way.
>>
>> You might also be able to do run groups of tests (such as all tests that use a given library) and then look for duplicate classes in the compiled classes directory. Such classes will generally be an indication of implicit compilation.
>>
>> -- Jon