--fully-export-maven-dependencies

The existing --auto-export-maven-dependencies flag has the effect of exporting every dependency Y of a maven module X to other maven modules that depend on X, but, confusingly for most people, it does not export Y to Ceylon modules that depend on X.

At least, I think that’s the right way to describe its effect.

The reasoning behind this was that the transitive dependencies of a maven module can include a whole heap of rubbish which just doesn’t affect the Ceylon program, and which would clog up IDE autocompletion, etc.

However, in practice, the need to explicitly specify a dependency on every dependency of a dependency (!) has been shown to be a major problem for people getting started in environments such as, for example, WildFly Swarm.

Worse, people are starting to invent workarounds like the Ceylon Gradle plugin’s generateOverridesFile command which generates a massive overrides.xml file which just exports all deps of all the maven modules, completely negating the “advantage” of not having --auto-export-maven-dependencies do it.

Therefore, I propose that we provide a second option, --fully-export-maven-dependencies, which exports transitive dependencies all the way to the Ceylon module. Even if it’s not ideal, it’s still a good way to get started when all else fails.

And it’s not like you can’t filter out stuff you don’t need. There are multiple ways to do that: overrides.xml, and IDE completion filters.

[FroMage]

So the first victory is that I now only get those errors when compiling:

test/src/com/redhat/ceylon/compiler/java/test/issues/bug65xx/bug6597/module.ceylon:1:ERROR:source code imports two different versions of module 'org.slf4j:slf4j-api': version '1.7.20' and version '1.7.21'
test/src/com/redhat/ceylon/compiler/java/test/issues/bug65xx/bug6597/module.ceylon:1:ERROR:source code imports two different versions of module 'org.jboss.logging:jboss-logging': version '3.1.3.GA' and version '3.2.1.Final'
test/src/com/redhat/ceylon/compiler/java/test/issues/bug65xx/bug6597/module.ceylon:1:ERROR:source code imports two different versions of module 'org.springframework:spring-core': version '4.1.9.RELEASE' and version '4.2.6.RELEASE'
test/src/com/redhat/ceylon/compiler/java/test/issues/bug65xx/bug6597/module.ceylon:1:ERROR:source code imports two different versions of module 'org.springframework:spring-beans': version '4.1.9.RELEASE' and version '4.2.6.RELEASE'
test/src/com/redhat/ceylon/compiler/java/test/issues/bug65xx/bug6597/module.ceylon:1:ERROR:source code imports two different versions of module 'org.springframework:spring-jdbc': version '4.1.9.RELEASE' and version '4.2.6.RELEASE'
test/src/com/redhat/ceylon/compiler/java/test/issues/bug65xx/bug6597/module.ceylon:1:ERROR:source code imports two different versions of module 'org.springframework:spring-tx': version '4.1.9.RELEASE' and version '4.2.6.RELEASE'
test/src/com/redhat/ceylon/compiler/java/test/issues/bug65xx/bug6597/module.ceylon:1:ERROR:source code imports two different versions of module 'org.springframework:spring-context': version '4.1.9.RELEASE' and version '4.2.6.RELEASE'
test/src/com/redhat/ceylon/compiler/java/test/issues/bug65xx/bug6597/module.ceylon:1:ERROR:source code imports two different versions of module 'org.springframework:spring-aop': version '4.1.9.RELEASE' and version '4.2.6.RELEASE'
test/src/com/redhat/ceylon/compiler/java/test/issues/bug65xx/bug6597/module.ceylon:1:ERROR:source code imports two different versions of module 'org.springframework.security:spring-security-crypto': version '3.2.7.RELEASE' and version '4.0.4.RELEASE'
test/src/com/redhat/ceylon/compiler/java/test/issues/bug65xx/bug6597/module.ceylon:1:ERROR:source code imports two different versions of module 'commons-logging:commons-logging': version '1.1.1' and version '1.2'
test/src/com/redhat/ceylon/compiler/java/test/issues/bug65xx/bug6597/module.ceylon:1:ERROR:source code imports two different versions of module 'com.fasterxml.jackson.core:jackson-annotations': version '2.6.0' and version '2.6.6'

And not the hundreds of duplicate errors.

[FroMage]

Does that mean that the IDE will introduce the corresponding import statements into the module descriptor when an IDE-proposed import from a transitive maven dependency is accepted?

yes