play framework dependecies

I am frequently gettin开发者_如何学Cg below error when I do the 'play dependencies'.

I am using play 1.2.2 and morphia 1.2.3d It is able to resolve morphia dependency, but throwing below error.

~
~ *****************************************************************************
~ WARNING: These dependencies are missing, your application may not work properl
y (use --verbose for details),
~
~       play->play 1.2
~ *****************************************************************************
~
~ Some dependencies are still missing.
~

When I add the line 'play->play 1.2' to conf/dependencies.yml file, it shows another error :

 ---------------------------------------------------------------------

:: problems summary ::
:::: WARNINGS
            module not found: play#play;1.2

    ==== playCore: tried

      E:\My_Pro\play_framewrk\play-1.2.2/framework/dependencies.yml

            ::::::::::::::::::::::::::::::::::::::::::::::

            ::          UNRESOLVED DEPENDENCIES         ::

            ::::::::::::::::::::::::::::::::::::::::::::::

            :: play#play;1.2: not found

            ::::::::::::::::::::::::::::::::::::::::::::::


:::: ERRORS
            playCore: unacceptable revision => was=1.2.2 required=1.2

Does this mean that , the higher versions of PLAY not downward compatible ?

Don't specify which version of play to use :

Your dependencies.yml :

# Application dependencies

require:
    - play
    - morphia 1.2.3d

As almost every application, Play is using Semantic Versioning syntax for their version number. Checkout the SemVer website for more information.

So an upgrade from 1.2 to 1.2.2 should not be dangerous. It is simply displaying a message saying that since the moduel was expplicitly tested for version 1.2 and no versions above. Meaning issues could appear.

http://www.playframework.org/modules/morphia-1.2.5a/start gives this:

require:
    - play -> morphia [1.2.4,)

I have no idea what this wonky syntax does, other than that it works.

I wish there were an explanation somewhere of what the syntax is for the dependencies.yml file. I found that when I just used 1.2.4 without the [,) it didn't work.