On Wed 20 Sep 2017 at 01:29, Igor Fedorenko <i...@ifedorenko.com> wrote:
> 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. That sounds like we need documentation updated then. None of that is obvious to me. > > * 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. Again, not obvious to me, if that file allows control of classpath visibility then it may be that the only issue *with* 3.5.1 is the lack of documentation... now previous versions would have been adding breaking changes from my PoV but that is the past and should not affect the 3.5.1 release. PRs for the probe project welcome. I am happy to try and write docs once I have an understanding of what the expected behaviours are > > -- > 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 > > -- Sent from my phone
