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
