In that case, can I suggest couple of changes to the test project * I thinks it makes more sense to configure extjar1 and extjar2 as extensions <plugin> elements in probleN pom.xml files. First, there is no meaningful order between <extensions> and <plugins> elements. More importantly, though, simple <extensions> are treated in special maven2-compat mode and are not representative of likely real-world extensions.
* I think we should introduce META-INF/maven/extension.xml to the test extensions. This metadata what introduced to configure classpath visibility, so lets use it. -- Regards, Igor On Tue, Sep 19, 2017, at 05:12 PM, Stephen Connolly wrote: > Yes, the expectations are key. Depending on what they are we may either > drop 3.5.1 or go ahead as it depends on whether this is more correct than > 3.5.0 or swapping one fix for a bug > > On Tue 19 Sep 2017 at 21:39, Igor Fedorenko <i...@ifedorenko.com> wrote: > > > Just to confirm I understand what we are trying to establish here. We > > want to decide the expected/desired component injection behaviour and > > classpath visibility in the absence of package and artifact export > > configuration (i.e. META-INF/maven/extension.xml file). Did I get this > > right? > > > > -- > > Regards, > > Igor > > > > On Tue, Sep 19, 2017, at 03:52 PM, Robert Scholte wrote: > > > Let's do it like this: > > > > > https://cwiki.apache.org/confluence/download/attachments/2329841/classrealms.pdf?api=v2 > > > > > > Robert > > > > > > On Tue, 19 Sep 2017 21:08:39 +0200, Stephen Connolly > > > <stephen.alan.conno...@gmail.com> wrote: > > > > > > > I think you will need a link to the PDF as attachments are stripped > > from > > > > the ML > > > > > > > > On Tue 19 Sep 2017 at 19:57, Robert Scholte <rfscho...@apache.org> > > wrote: > > > > > > > >> Attached a single page overview. > > > >> > > > >> Per block you'll see in the upper left corner the executed plugin > > > >> The left column contains the extensions and plugin in orderas > > specified > > > >> in > > > >> the pom.xml > > > >> In every classloadercolumn you'll see numbers which represent the > > order. > > > >> > > > >> I hope I didn't make any mistakes. > > > >> Tomorrow I have enough time to see if I understand what's happening > > > >> here. > > > >> > > > >> I will come back with my conclusions. > > > >> > > > >> Robert > > > >> > > > >> On Tue, 19 Sep 2017 06:55:08 +0200, Igor Fedorenko < > > i...@ifedorenko.com> > > > >> wrote: > > > >> > > > >> > TL;DR your test project exposed two existing bugs, one change in > > > >> > behaviour and one quirk I can't explain > > > >> > > > > >> > * Build `<extensions>` are loaded by two classloaders, which is a > > bug > > > >> in > > > >> > DefaultProjectBuildingHelper#createProjectRealm and explains why you > > > >> see > > > >> > extjar1/extjar2 in the output > > > >> > * ClassRealm does not allow same foreign-import from multiple > > > >> > classloaders, which is a bug and explains why it is not possible to > > > >> load > > > >> > same resource from multiple plugins/extensions > > > >> > * TCCL does not have access to private (i.e. not exported) resources > > > >> of > > > >> > this extensions plugin, which is a change of behaviour introduced by > > > >> > mng-6209 fix > > > >> > * Also, component injection order appears to be backwards, but maybe > > > >> > Stuart can explain why. > > > >> > > > > >> > > > > >> > Below is more detailed explanation of expected and observed > > behaviour > > > >> > > > > >> > > > > >> > ## Component injection depends on the currently running plugin and > > the > > > >> > injection site > > > >> > > > > >> > Currently running plugins have access to the following component > > > >> > implementations: > > > >> > > > > >> > * Regular plugin has access to components implemented by the plugin, > > > >> > project build extensions, if any (via project class realm foreign > > > >> > import) and Maven Core. > > > >> > * Extension plugin has access to components implemented by the > > project > > > >> > build extensions and Maven Core. > > > >> > * Without a running plugin (e.g., during project dependency > > > >> resolution), > > > >> > components implemented by the project build extensions and Maven > > Core > > > >> > are accessible. > > > >> > > > > >> > Different injection sites have access to the following component > > > >> > interfaces: > > > >> > > > > >> > * Maven Core has access to component interfaces defined by the core > > > >> > itself (obviously) > > > >> > * Project build extensions have access to **public** component > > > >> > interfaces defined by Maven Core and component interfaces defined by > > > >> the > > > >> > build extension itself (there is no way to access component > > interfaces > > > >> > defined in other extensions) > > > >> > * Regular plugins have access to **public** component interfaces > > > >> defined > > > >> > by Maven Core, component interfaces **exported** by build extensions > > > >> and > > > >> > component interfaces defined in the plugin itself > > > >> > > > > >> > For injection to work, injection site has to have access to the > > > >> > component interface and the component implementation must be > > > >> accessible > > > >> > through the current context. > > > >> > > > > >> > From what I can tell, in your example all plugins have access to the > > > >> > right components when using current 3.5.2-SNAPSHOT. The injection > > > >> order > > > >> > does appear to be backwards from what I expected, however. > > > >> > > > > >> > > > > >> > ## Resources lookup fully depends on classpath visibility, > > > >> specifically > > > >> > > > > >> > * Regular plugin class realm has access to resources from the plugin > > > >> > itself, from **exported** packages of the project build extensions > > and > > > >> > **public** Maven Core packages > > > >> > * Extensions plugin class realm has access to the resources from the > > > >> > extensions plugin itself and from **public** Maven Core packages > > > >> > * Project class realm has access to classes and resources > > **exported** > > > >> > by project build extensions and **public** Maven Core packages > > > >> > > > > >> > I see three problems here > > > >> > > > > >> > * Maven adds build single-jar `<extensions>` elements directly to > > > >> > project class realm **and** creates separate extensions class realms > > > >> for > > > >> > them. Which results in duplicate classes/resources loaded by two > > > >> > classloaders and explains why you see extjar1/extjar2 output (which > > > >> you > > > >> > shouldn't according to the explanation above) > > > >> > * ClassRealm does not allow foreign-import of the same package from > > > >> > multiple classloaders. This makes it impossible to load the same > > > >> > resource from multiple plugins/extensions. > > > >> > * Extensions plugins cannot access their own private (i.e. not > > > >> exported) > > > >> > resources via TCCL, this is change in behaviour introduced by > > mng-6209 > > > >> > fix > > > >> > > > > >> > Hope this helps > > > >> > > > >> --------------------------------------------------------------------- > > > >> To unsubscribe, e-mail: dev-unsubscr...@maven.apache.org > > > >> For additional commands, e-mail: dev-h...@maven.apache.org > > > > > > --------------------------------------------------------------------- > > > To unsubscribe, e-mail: dev-unsubscr...@maven.apache.org > > > For additional commands, e-mail: dev-h...@maven.apache.org > > > > > > > --------------------------------------------------------------------- > > To unsubscribe, e-mail: dev-unsubscr...@maven.apache.org > > For additional commands, e-mail: dev-h...@maven.apache.org > > > > -- > Sent from my phone --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@maven.apache.org For additional commands, e-mail: dev-h...@maven.apache.org
