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Posted to users@maven.apache.org by Marco Speranza <ma...@apache.org> on 2012/07/17 14:44:14 UTC
transitive provided dependencies: a little question
Hi all...
a friend of mine and I have experienced a compilation error when we
have tried to compile this project:
prj.a:
public class A extends B{}
prj.b:
public class B extends C{}
prj.c:
public class C{}
where their pom are:
prj.a -> prj.b (provided scope)
prj.b -> prj.c (provided scope)
our compilation fails because C is not included in A's compile
classpath as shown in the table [1]
My question is... why the transitive 'provided' dependencies of a
'provided' dependency are not transitive and the transitive
*'runtime'* dependencies of a 'provided' dependency is transitive?
IMHO would be better that provided dependencies are transitive and
runtime dependencies not, it isn't?
have a nice day... :-)
[1]: http://maven.apache.org/guides/introduction/introduction-to-dependency-mechanism.html#Dependency_Scope
--
Marco Speranza <ma...@apache.org>
Google Code: http://code.google.com/u/marco.speranza79/
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Re: transitive provided dependencies: a little question
Posted by Marco Speranza <ma...@apache.org>.
Hi Ron...
yes I understood your point.. but some days ago I tried to compile a
project like this:
prj.a:
public class A extends B{}
prj.b:
public class B extends C{}
prj.c:
public class C{}
where their pom are:
prj.a -> prj.b (provided scope)
prj.b -> prj.c (provided scope)
is strange... but the build fails because A extends B and A needs to
know also C at compile time..
Could you try to compile my example?
thank a lot...
regards
--
Marco Speranza <ma...@apache.org>
Google Code: http://code.google.com/u/marco.speranza79/
2012/7/18 Ron Wheeler <rw...@artifact-software.com>:
> On 18/07/2012 12:23 PM, Marco Speranza wrote:
>>
>> Hi
>>
>> thanks for your reply... I read the maven dependency mechanism and I
>> understud how it's works...
>>
>> The definition of 'provided' scope is that "is only available on the
>> compilation and test classpath" and the user should provide the
>> dependency at runtime.
>> And the definition of 'runtime' scopoe is that "the dependency is not
>> required for compilation"
>>
>> so my question is: why the provided transitive dependency is NOT
>> included in 'compile' classpath and the 'runtime' transitive
>> dependency IS included in the compile classpath?
>>
>> Furthermore IMHO this behavior could break some builds (see my little
>> example) because if the project A needs B at compile time and the
>> project B needs C at compile time.. for the 'transitivity' theorem
>> also A might need of C at compile time, isn't it?.
>
>
> Why would the compiler even care about C when compiling A?
> It only has references to B that it needs to resolve.
> Lets say that I use Apache's log4j. My code only refers to log4j objects and
> my code does not have any references to the objects that log4j uses.
>
> At runtime, my code will run just fine as long as the log4j.jar has in it
> all of the things that log4j requires to perform its functions.
>
> Remember:
> The current system works for thousands of projects every day with tens of
> thousands of developers using "provided" and "compile" scopes successfully.
>
>
> Ron
>
>
>>
>> thanks
>> ciao
>> --
>> Marco Speranza <ma...@apache.org>
>> Google Code: http://code.google.com/u/marco.speranza79/
>>
>>
>> 2012/7/18 abhijith tn <ab...@gmail.com>:
>>>
>>> Hi Marco,
>>>
>>> It is very simple. Maven stops searching for the dependency when it finds
>>> provided scope and maven assumes the dependency will be provided
>>> externally. Best example being server library jars like servlet-api jar.
>>>
>>> Below link will give you clear picture
>>>
>>>
>>> http://maven.apache.org/guides/introduction/introduction-to-dependency-mechanism.html#Dependency_Scope
>>>
>>> On Tue, Jul 17, 2012 at 2:44 PM, Marco Speranza
>>> <ma...@apache.org>wrote:
>>>
>>>> Hi all...
>>>>
>>>> a friend of mine and I have experienced a compilation error when we
>>>> have tried to compile this project:
>>>>
>>>> prj.a:
>>>> public class A extends B{}
>>>>
>>>> prj.b:
>>>> public class B extends C{}
>>>>
>>>> prj.c:
>>>> public class C{}
>>>>
>>>> where their pom are:
>>>>
>>>> prj.a -> prj.b (provided scope)
>>>>
>>>> prj.b -> prj.c (provided scope)
>>>>
>>>> our compilation fails because C is not included in A's compile
>>>> classpath as shown in the table [1]
>>>>
>>>> My question is... why the transitive 'provided' dependencies of a
>>>> 'provided' dependency are not transitive and the transitive
>>>> *'runtime'* dependencies of a 'provided' dependency is transitive?
>>>>
>>>> IMHO would be better that provided dependencies are transitive and
>>>> runtime dependencies not, it isn't?
>>>>
>>>>
>>>> have a nice day... :-)
>>>>
>>>>
>>>> [1]:
>>>>
>>>> http://maven.apache.org/guides/introduction/introduction-to-dependency-mechanism.html#Dependency_Scope
>>>>
>>>>
>>>> --
>>>> Marco Speranza <ma...@apache.org>
>>>> Google Code: http://code.google.com/u/marco.speranza79/
>>>>
>>>> ---------------------------------------------------------------------
>>>> To unsubscribe, e-mail: users-unsubscribe@maven.apache.org
>>>> For additional commands, e-mail: users-help@maven.apache.org
>>>>
>>>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: users-unsubscribe@maven.apache.org
>> For additional commands, e-mail: users-help@maven.apache.org
>>
>>
>
>
> --
> Ron Wheeler
> President
> Artifact Software Inc
> email: rwheeler@artifact-software.com
> skype: ronaldmwheeler
> phone: 866-970-2435, ext 102
>
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@maven.apache.org
> For additional commands, e-mail: users-help@maven.apache.org
>
---------------------------------------------------------------------
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Re: transitive provided dependencies: a little question
Posted by Ron Wheeler <rw...@artifact-software.com>.
On 18/07/2012 12:23 PM, Marco Speranza wrote:
> Hi
>
> thanks for your reply... I read the maven dependency mechanism and I
> understud how it's works...
>
> The definition of 'provided' scope is that "is only available on the
> compilation and test classpath" and the user should provide the
> dependency at runtime.
> And the definition of 'runtime' scopoe is that "the dependency is not
> required for compilation"
>
> so my question is: why the provided transitive dependency is NOT
> included in 'compile' classpath and the 'runtime' transitive
> dependency IS included in the compile classpath?
>
> Furthermore IMHO this behavior could break some builds (see my little
> example) because if the project A needs B at compile time and the
> project B needs C at compile time.. for the 'transitivity' theorem
> also A might need of C at compile time, isn't it?.
Why would the compiler even care about C when compiling A?
It only has references to B that it needs to resolve.
Lets say that I use Apache's log4j. My code only refers to log4j objects
and my code does not have any references to the objects that log4j uses.
At runtime, my code will run just fine as long as the log4j.jar has in
it all of the things that log4j requires to perform its functions.
Remember:
The current system works for thousands of projects every day with tens
of thousands of developers using "provided" and "compile" scopes
successfully.
Ron
>
> thanks
> ciao
> --
> Marco Speranza <ma...@apache.org>
> Google Code: http://code.google.com/u/marco.speranza79/
>
>
> 2012/7/18 abhijith tn <ab...@gmail.com>:
>> Hi Marco,
>>
>> It is very simple. Maven stops searching for the dependency when it finds
>> provided scope and maven assumes the dependency will be provided
>> externally. Best example being server library jars like servlet-api jar.
>>
>> Below link will give you clear picture
>>
>> http://maven.apache.org/guides/introduction/introduction-to-dependency-mechanism.html#Dependency_Scope
>>
>> On Tue, Jul 17, 2012 at 2:44 PM, Marco Speranza <ma...@apache.org>wrote:
>>
>>> Hi all...
>>>
>>> a friend of mine and I have experienced a compilation error when we
>>> have tried to compile this project:
>>>
>>> prj.a:
>>> public class A extends B{}
>>>
>>> prj.b:
>>> public class B extends C{}
>>>
>>> prj.c:
>>> public class C{}
>>>
>>> where their pom are:
>>>
>>> prj.a -> prj.b (provided scope)
>>>
>>> prj.b -> prj.c (provided scope)
>>>
>>> our compilation fails because C is not included in A's compile
>>> classpath as shown in the table [1]
>>>
>>> My question is... why the transitive 'provided' dependencies of a
>>> 'provided' dependency are not transitive and the transitive
>>> *'runtime'* dependencies of a 'provided' dependency is transitive?
>>>
>>> IMHO would be better that provided dependencies are transitive and
>>> runtime dependencies not, it isn't?
>>>
>>>
>>> have a nice day... :-)
>>>
>>>
>>> [1]:
>>> http://maven.apache.org/guides/introduction/introduction-to-dependency-mechanism.html#Dependency_Scope
>>>
>>>
>>> --
>>> Marco Speranza <ma...@apache.org>
>>> Google Code: http://code.google.com/u/marco.speranza79/
>>>
>>> ---------------------------------------------------------------------
>>> To unsubscribe, e-mail: users-unsubscribe@maven.apache.org
>>> For additional commands, e-mail: users-help@maven.apache.org
>>>
>>>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@maven.apache.org
> For additional commands, e-mail: users-help@maven.apache.org
>
>
--
Ron Wheeler
President
Artifact Software Inc
email: rwheeler@artifact-software.com
skype: ronaldmwheeler
phone: 866-970-2435, ext 102
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@maven.apache.org
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Re: transitive provided dependencies: a little question
Posted by Marco Speranza <ma...@apache.org>.
Hi
thanks for your reply... I read the maven dependency mechanism and I
understud how it's works...
The definition of 'provided' scope is that "is only available on the
compilation and test classpath" and the user should provide the
dependency at runtime.
And the definition of 'runtime' scopoe is that "the dependency is not
required for compilation"
so my question is: why the provided transitive dependency is NOT
included in 'compile' classpath and the 'runtime' transitive
dependency IS included in the compile classpath?
Furthermore IMHO this behavior could break some builds (see my little
example) because if the project A needs B at compile time and the
project B needs C at compile time.. for the 'transitivity' theorem
also A might need of C at compile time, isn't it?.
thanks
ciao
--
Marco Speranza <ma...@apache.org>
Google Code: http://code.google.com/u/marco.speranza79/
2012/7/18 abhijith tn <ab...@gmail.com>:
> Hi Marco,
>
> It is very simple. Maven stops searching for the dependency when it finds
> provided scope and maven assumes the dependency will be provided
> externally. Best example being server library jars like servlet-api jar.
>
> Below link will give you clear picture
>
> http://maven.apache.org/guides/introduction/introduction-to-dependency-mechanism.html#Dependency_Scope
>
> On Tue, Jul 17, 2012 at 2:44 PM, Marco Speranza <ma...@apache.org>wrote:
>
>> Hi all...
>>
>> a friend of mine and I have experienced a compilation error when we
>> have tried to compile this project:
>>
>> prj.a:
>> public class A extends B{}
>>
>> prj.b:
>> public class B extends C{}
>>
>> prj.c:
>> public class C{}
>>
>> where their pom are:
>>
>> prj.a -> prj.b (provided scope)
>>
>> prj.b -> prj.c (provided scope)
>>
>> our compilation fails because C is not included in A's compile
>> classpath as shown in the table [1]
>>
>> My question is... why the transitive 'provided' dependencies of a
>> 'provided' dependency are not transitive and the transitive
>> *'runtime'* dependencies of a 'provided' dependency is transitive?
>>
>> IMHO would be better that provided dependencies are transitive and
>> runtime dependencies not, it isn't?
>>
>>
>> have a nice day... :-)
>>
>>
>> [1]:
>> http://maven.apache.org/guides/introduction/introduction-to-dependency-mechanism.html#Dependency_Scope
>>
>>
>> --
>> Marco Speranza <ma...@apache.org>
>> Google Code: http://code.google.com/u/marco.speranza79/
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: users-unsubscribe@maven.apache.org
>> For additional commands, e-mail: users-help@maven.apache.org
>>
>>
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@maven.apache.org
For additional commands, e-mail: users-help@maven.apache.org
Re: transitive provided dependencies: a little question
Posted by abhijith tn <ab...@gmail.com>.
Hi Marco,
It is very simple. Maven stops searching for the dependency when it finds
provided scope and maven assumes the dependency will be provided
externally. Best example being server library jars like servlet-api jar.
Below link will give you clear picture
http://maven.apache.org/guides/introduction/introduction-to-dependency-mechanism.html#Dependency_Scope
On Tue, Jul 17, 2012 at 2:44 PM, Marco Speranza <ma...@apache.org>wrote:
> Hi all...
>
> a friend of mine and I have experienced a compilation error when we
> have tried to compile this project:
>
> prj.a:
> public class A extends B{}
>
> prj.b:
> public class B extends C{}
>
> prj.c:
> public class C{}
>
> where their pom are:
>
> prj.a -> prj.b (provided scope)
>
> prj.b -> prj.c (provided scope)
>
> our compilation fails because C is not included in A's compile
> classpath as shown in the table [1]
>
> My question is... why the transitive 'provided' dependencies of a
> 'provided' dependency are not transitive and the transitive
> *'runtime'* dependencies of a 'provided' dependency is transitive?
>
> IMHO would be better that provided dependencies are transitive and
> runtime dependencies not, it isn't?
>
>
> have a nice day... :-)
>
>
> [1]:
> http://maven.apache.org/guides/introduction/introduction-to-dependency-mechanism.html#Dependency_Scope
>
>
> --
> Marco Speranza <ma...@apache.org>
> Google Code: http://code.google.com/u/marco.speranza79/
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@maven.apache.org
> For additional commands, e-mail: users-help@maven.apache.org
>
>