[fedora-java] Gradle upgrade issues (#976330)

[Dridi Boukelmoune]

Hi,

How about converting graddle.build files to pom.xml files [1] ? This
could be the bootstrap we need for the build part, but I have no idea
whether it would actually be simpler.

Dridi

[1] http://www.gradle.org/docs/current/userguide/maven_plugin.html#sec:maven_pom_generation

On Mon, Oct 21, 2013 at 5:55 PM, Mikolaj Izdebski <mizdebsk at redhat.com> wrote:
> On 10/21/2013 05:11 PM, Michael Ekstrand wrote:
>> In bug #976330[1], there's been some discussion of the desire to
>> upgrade Gradle from 1.0 to a new version (currently 1.8), and that
>> there is significant hassle to actually do so.  Some of this hassle I
>> see in the bugs blocking 976330 - upgrading to Aether, newer Plexus
>> containers, and maybe Polyglot Maven.
>>
>> What are the key issues that make it difficult to upgrade and maintain
>> Gradle in Fedora?  The likely ones I see:
>>
>> - Incompatible dependencies (Gradle may require package versions no
>>   longer shipped in Fedora)
>
> Gradle used to use (very) old versions of some dependencies, for example
> legacy pre-1.0 alpha version of Plexus, released ~10 years ago.  It also
> used some Maven 2 APIs (Fedora ships Maven 3 only).  This was improved
> recently IIRC.
>
> Gradle also uses Sonatype Aether, which is not in Fedora any longer.
> Porting it to Eclipse Aether should be fairly straightforward, but
> still, needs to be done.
>
>> - Bootstrapping problems (the Gradle 1.8 sources won't build with
>>   Gradle 1.8, they seem to require 1.7)
>
> These are IMO two separate problems.
>
> 1. Gradle breaks compatibility between releases.  If package builds with
> Gradle version X then it not necessarily builds with Gradle version Y, Y
>> X.  This is a serious problem as Fedora may have to maintain multiple
> versions of Gradle to build different projects.  Other build systems may
> have some incompatibilities too, but in case of Gradle they are causing
> more problems.  Additionally, Gradle build scripts are written in
> fully-featured programming language and may not be so easy to port to
> different version of Gradle.
>
> 2. Gradle is built with itself (as many build systems are), so it needs
> bootstrapping.  Upstream of majority of other build systems (including
> Ant or Maven) are maintaining secondary ways of building them (Ant can
> be built with javac, Maven can be built with Ant etc.), but Gradle
> upstream does not provide any way to bootstrap Gradle.  Normally
> bootstrapping would need to be performed only once, but because of 1.
> bootstrapping may be required more often, worst case with every release.
>
> Fedora would probably need to create and maintain a separate build
> script for Gradle (for example using Ant or Maven) or obtain an
> exception from FPC to build using prebuilt binaries.  Currently Fedora
> ships Ant build.xml for Gradle, but it requires substantial amount of
> manual work to synchronize it with upstream build.  (I would prefer to
> use Maven here.  It would not only ease dependency management, but also
> allow easier installation of Gradle artifacts.)
>
>> - Possibly library embedding (although the Gradle sources do seem to
>>   pull in the dependencies from Maven)
>
> That's a generic problem and it's not really Gradle-specific.  But yes,
> there are some version problems, most notably Objectweb ASM.  Different
> Gradle dependencies use versions 3 and 4 (shaded to avoid namespace
> conflicts).  Fedora does not allow bundled libraries, which causes
> conflict between ASM 3 and 4.  (Porting from ASM 3 to ASM 4 is possible,
> but non-trivial as there were major changes. This would again require
> some work.)
>
> To sum up, Gradle maintainence requires substantial amount of work.
> Currently only few packages in Fedora are using Gradle which means that
> maintenance costs of Gradle outweight costs of porting other packages to
> different build systems.
>
> --
> Mikolaj Izdebski
> IRC: mizdebsk
>
> PS. Integration of Gradle with Fedora is a completely different story...
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