Re: [m2e-dev] Scanning for modified resources (BuildContext vs other mea

[Anders Hammar <anders@xxxxxxxxxx>]

Thanks Igor! I've mailed you my personal info privately.

The new incremental build API is very interesting. I've updated a few Mojo plugins in the past with m2e support and the biggest issue I've seen so far is the DefaultBuildContext implementation (used for command-line executions) which effectively says everything has always changed. Which has forced me to implemented separate detection in the plugin depending on the BuildContext impl.

Are there any plans on providing a better BuildContext for command-line executions?

Also, looking into adding m2e compliance to the java.net jaxws-maven-plugin I've found an edge case. That plugin supports specifying an external wsdl as the resource (by an URL). Typically I would strongly argue against having external resources like this, but it's a live case which I'm not sure how to handle with incremental support. Any thoughts on this?

/Anders

On Mon, Mar 10, 2014 at 7:22 PM, Igor Fedorenko <igor@xxxxxxxxxxxxxx> wrote:

Cool. Can you email me your github userid and the email address you want
me to subscribe to our dev google group?

Just to give you quick overview of what you are signing up for ;-)

We plan to release this in several stages.

First we'll provide new version of BuildContext API, which we call
"incremental build API" and also some high-level overview what it does.
The main target audience here are Maven developers but other build tool
authors may also be interested. Then we'll open (fully and properly)
incremental Maven java compiler plugin. Last, but not least of course,
will be m2e integration.

Right now we are looking for feedback on incremental build API. Does the
API work for your usecases? Do names make sense? Anything looks odd or
unnecessary complicated? And so on.

--
Regards,
Igor

On 2014-03-09, 14:10, Anders Hammar wrote:

Thanks for the very informative clarification, Igor!

And yes, I would absolutely be interested in becoming an early adopter
of the new version of the BuildContext API.

/Anders


On Fri, Mar 7, 2014 at 2:28 PM, Igor Fedorenko <igor@xxxxxxxxxxxxxx

<mailto:igor@xxxxxxxxxxxxxx>> wrote:



    On 2014-03-07, 7:42, Anders Hammar wrote:

        According to [1], it says that a maven plugin "MUST use
        BuildContext to
        skip execution when there none of relevant workspace resources
        changed".

        Is it required to use BuildContext, or can I use some other means to
        determine if the plugin should skip execution? I'm asking as several
        plugin already has a similar functionality through a stale file. I
        appreciate that it might not be 100% the same, but close enough
        IMHO.

        So, bottom line, it the requirement to skip execution when there
        hasn't
        been any relevant resource changes or is the requirement to use
        BuildContext to determine that?


    tl;dr yes, correct mojo implementation requires use of BuildContext

    All this applies to mojos that modify filesystem, i.e. create, modify or
    delete files. Mojos that only modify MavenProject state should be safe
    to run without any checks and m2e is expected to maintain consistent
    MavenProject.

    For mojos that do modify filesystem need to be aware of there build
    types

    * Configuration build is performed during project import and
    configuration update. Mojos are not expected to do any resource
    processing during configuration build and Eclipse/m2e use empty
    BuildContext to make mojos skip execution. Project is not fully setup at
    this point and mojo execution is likely to fail, because dependency
    classes are not available yet, for example. Even if execution does not
    fail, it will unnecessary slow down project import and configuration
    update.

    * Full build is performed when user selects "Project/Clean..." action
    and BuildContext provided by m2e will list all resources as modified.

    * Incremental build is performed on each workspace resource
    modification. To avoid endless workspace builds it is absolutely
    essential to to skip mojo execution if there are no relevant changes.
    Mojo execution may use other means to do that, I suppose, but you I'd
    still use BuildContext to make it easier to reason about mojo
    implementation.

    Btw, we are working on new version of BuildContext API that will provide
    proper incremental build behaviour during command line build too, so
    mojos will not need to implement custom stale file detection logic
    (which is pretty tricky to implement correctly). I may be able to give
    you access to the code if you are interested to become an early adopter.


    --
    Regards,
    Igor

        /Anders

        [1] http://wiki.eclipse.org/M2E___compatible_maven_plugins
        <http://wiki.eclipse.org/M2E_compatible_maven_plugins>

    _________________________________________________
    m2e-dev mailing list
    m2e-dev@xxxxxxxxxxx <mailto:m2e-dev@xxxxxxxxxxx>
    https://dev.eclipse.org/__mailman/listinfo/m2e-dev
    <https://dev.eclipse.org/mailman/listinfo/m2e-dev>

_______________________________________________
m2e-dev mailing list
m2e-dev@xxxxxxxxxxx
https://dev.eclipse.org/mailman/listinfo/m2e-dev

_______________________________________________
m2e-dev mailing list
m2e-dev@xxxxxxxxxxx
https://dev.eclipse.org/mailman/listinfo/m2e-dev