Bumping Maven compiler source/target to 1.6

[Mikolaj Izdebski]

I'm considering bumping minimal source/target values in Maven Compiler
Plugin to 1.6 starting from Fedora 23. What is your opinion?

Java 9 is going to drop support for compiling for targets < 1.6.
This change would allow us to notice some problems earlier and give us
more time for fixing them.

Currently XMvn ensures that all Maven builds are compiled with
source/target of 1.5 and that target >= source (this is to avoid
problems caused by JSR-14).

The proposed change would adjust source/target used by Maven Compiler
Plugin when building RPM packages, according to the following snippet:

    source = max(source, 1.6)
    target = max(target, source)

Are there any objections?

-- 
Mikolaj Izdebski
Software Engineer, Red Hat
IRC: mizdebsk

[Jiri Vanek]

On 02/06/2015 02:37 PM, Mikolaj Izdebski wrote:
>  I'm considering bumping minimal source/target values in Maven
> Compiler
>  Plugin to 1.6 starting from Fedora 23. What is your opinion? 
I would vote even for f22.


Anyway it is +1 for this effort.
>  Java 9 is going to drop support for compiling for targets < 1.6.
>  This change would allow us to notice some problems earlier and give us
>  more time for fixing them.
>
>  Currently XMvn ensures that all Maven builds are compiled with
>  source/target of 1.5 and that target >= source (this is to avoid
>  problems caused by JSR-14).
>
>  The proposed change would adjust source/target used by Maven Compiler
>  Plugin when building RPM packages, according to the following snippet:
>
>       source = max(source, 1.6)
>       target = max(target, source)
>  
Thank you!

    J.

[Mikolaj Izdebski]

On 02/06/2015 02:40 PM, Jiri Vanek wrote:
>  On 02/06/2015 02:37 PM, Mikolaj Izdebski wrote:
> > I'm considering bumping minimal source/target values in Maven Compiler
> > Plugin to 1.6 starting from Fedora 23. What is your opinion?
>  
>  I would vote even for f22. 
I'd rather keep this for F23 only because:

- there is no immediate benefit from this change - Java
  keeps support for all bytecode formats,

- there won't be mass rebuild for F22 - we won't notice
  if this breaks some packages until some update needs
  to be pushed,

- continous integration won't catch this in F22 - Koschei
  will move to F23 immediately after branching.

-- 
Mikolaj Izdebski
Software Engineer, Red Hat
IRC: mizdebsk

[Aleksandar Kurtakov]

----- Original Message -----
>  From: "Mikolaj Izdebski" <mizdebsk(a)redhat.com&gt;
>  To: "Fedora Java Development List" <java-devel(a)lists.fedoraproject.org&gt;
>  Sent: Friday, February 6, 2015 3:47:34 PM
>  Subject: Re: [fedora-java] Bumping Maven compiler source/target to 1.6
>  
>  On 02/06/2015 02:40 PM, Jiri Vanek wrote:
>  > On 02/06/2015 02:37 PM, Mikolaj Izdebski wrote:
>  >> I'm considering bumping minimal source/target values in Maven Compiler
>  >> Plugin to 1.6 starting from Fedora 23. What is your opinion?
>  > 
>  > I would vote even for f22.
>  
>  I'd rather keep this for F23 only because:
>  
>  - there is no immediate benefit from this change - Java
>    keeps support for all bytecode formats,
>  
>  - there won't be mass rebuild for F22 - we won't notice
>    if this breaks some packages until some update needs
>    to be pushed,
>  
>  - continous integration won't catch this in F22 - Koschei
>    will move to F23 immediately after branching. 
Huge +1.

P.S. I wouldn't mind even 1.7 :).

Alexander Kurtakov
Red Hat Eclipse team

>  
>  --
>  Mikolaj Izdebski
>  Software Engineer, Red Hat
>  IRC: mizdebsk
>  --
>  java-devel mailing list
>  java-devel(a)lists.fedoraproject.org
>  https://admin.fedoraproject.org/mailman/listinfo/java-devel

[Christopher]

On Fri, Feb 6, 2015 at 8:37 AM, Mikolaj Izdebski <mizdebsk(a)redhat.com&gt;
wrote:

>  I'm considering bumping minimal source/target values in Maven
> Compiler
>  Plugin to 1.6 starting from Fedora 23. What is your opinion?
>
>  [snip] 
+1, with questions:

1. Does this mean that F23 will ship Java 9?
2. What is the upstream maven-compiler-plugin doing regarding their
defaults? If they are doing nothing, would it be better to simply fail to
build if source/target aren't specified, in order to avoid diverging in
expected behavior from upstream parsing of the POM?

--
Christopher L Tubbs II
http://gravatar.com/ctubbsii

[Mikolaj Izdebski]

On 02/06/2015 04:56 PM, Christopher wrote:
>  On Fri, Feb 6, 2015 at 8:37 AM, Mikolaj Izdebski
> <mizdebsk(a)redhat.com&gt;
>  wrote:
>  
> > I'm considering bumping minimal source/target values in Maven Compiler
> > Plugin to 1.6 starting from Fedora 23. What is your opinion?
> >
> > [snip]
>  
>  +1, with questions:
>  
>  1. Does this mean that F23 will ship Java 9? 
No, I don't know anything plans for packaging java-1.9.0-openjdk.

>  2. What is the upstream maven-compiler-plugin doing regarding their
>  defaults? If they are doing nothing, would it be better to simply fail to
>  build if source/target aren't specified, in order to avoid diverging in
>  expected behavior from upstream parsing of the POM? 
This depends on plugin version. I think that in the latest version
default is 1.5.

Most of projects we ship define source/target, but sometimes it's quite
low. There a few project with 1.4 or 1.3 sources, some of which use
"enum" or "assert" as identifiers (or have other problems) and
can't be
compiled with higher source levels.

As of today 1.5 is still definitely the most popular source level used
in Fedora packages. I wouldn't want to fail builds of hundreds of
packages and force maintainers to patch them manually. That's why XMvn
adjusts compiler plugin configuration at build time.

-- 
Mikolaj Izdebski
Software Engineer, Red Hat
IRC: mizdebsk

[Jiri Vanek]

On 02/06/2015 04:56 PM, Christopher wrote:
>  On Fri, Feb 6, 2015 at 8:37 AM, Mikolaj Izdebski
> <mizdebsk(a)redhat.com <mailto:[e-mail]>>
>  wrote:
>
>      I'm considering bumping minimal source/target values in Maven Compiler
>      Plugin to 1.6 starting from Fedora 23. What is your opinion?
>
>  [snip]
>
>  +1, with questions:
>
>  1. Does this mean that F23 will ship Java 9? 

Very probably yes. But definitely as techpreview.


J.