Optional dependencies

[ocroquette]

Hi,

I create a bundle from commons-logging:
dependencies { platform 'commons-logging:commons-logging:1.1.1' }

It has an optional dependency to Avalon:
<dependency> <groupId>avalon-framework</groupId> <artifactId>avalon-framework</artifactId> <version>4.1.3</version> <optional>true</optional> </dependency>

It looks like bnd-platform makes a hard dependency at out it:
Import-Package: javax.servlet,org.apache.avalon.framework.logger,org.apa che.log,org.apache.log4j

Is that expected? In other words, do pnd-platform support optional dependencies automatically?
If not, is there a workaround? I tried various things, like using override and importIgnorePackages, but nothing worked unfortunately.

[stempler]

Gradle does not support optional dependencies in its dependency management, so that information is lost.

Workaround is easy if you know the bundle where you want to make the dependency optional and the respective package names. You can configure the bundle to use optional package imports, similar to the first example here.

[ocroquette]

Thanks for the quick reply. I tried that, but it's not working, so I must do something wrong. Here is my script:

buildscript {
  repositories {
      jcenter()
  }
  dependencies {
      classpath 'org.standardout:bnd-platform:1.4.0'
  }
}

repositories {
  mavenCentral()
}

apply plugin: 'org.standardout.bnd-platform'

dependencies {
  platform 'commons-logging:commons-logging:1.1.1'
}

platform {
  bnd(group: 'commons-logging', name: 'commons-logging') {
      optionalImport 'org.apache.avalon.framework.logger'
  }
}

And here is the generated manifest:

Manifest-Version: 1.0
Archiver-Version: Plexus Archiver
Build-Jdk: 1.4.2_16
Built-By: dlg01
Bundle-ManifestVersion: 2
Bundle-Name: commons-logging.commons-logging
Bundle-SymbolicName: commons-logging
Bundle-Version: 1.1.1.bnd-u8sQ6Q
Export-Package: org.apache.commons.logging;version="1.1.1",org.apache.co
 mmons.logging.impl;version="1.1.1";uses:="javax.servlet,org.apache.aval
 on.framework.logger,org.apache.commons.logging,org.apache.log,org.apach
 e.log4j"
Extension-Name: org.apache.commons.logging
Implementation-Title: Jakarta Commons Logging
Implementation-Vendor: Apache Software Foundation
Implementation-Vendor-Id: org.apache
Implementation-Version: 1.1.1
Import-Package: javax.servlet,org.apache.avalon.framework.logger,org.apache.log,org.apache.log4j
Originally-Created-By: Apache Maven
Specification-Title: Jakarta Commons Logging
Specification-Vendor: Apache Software Foundation
Specification-Version: 1.0
X-Compile-Source-JDK: 1.2
X-Compile-Target-JDK: 1.2

[stempler]

Strange, the configuration looks alright. Does it make a difference if you use org.apache.avalon.framework.logger.* or org.apache.avalon.framework.* for the optional import instruction?

[ocroquette]

Hmmm, no, it doesn't.

I also tried this as a cross check:

      optionalImport 'javax.servlet'

It doesn't have any effect either.

[stempler]

Just copied your build.gradle and let it run locally, this is the Manifest I get:

Manifest-Version: 1.0
Archiver-Version: Plexus Archiver
Build-Jdk: 1.4.2_16
Built-By: dlg01
Bundle-ManifestVersion: 2
Bundle-Name: commons-logging.commons-logging
Bundle-SymbolicName: commons-logging
Bundle-Version: 1.1.1.bnd-5zkmsg
Export-Package: org.apache.commons.logging;version="1.1.1",org.apache.co
 mmons.logging.impl;version="1.1.1";uses:="javax.servlet,org.apache.aval
 on.framework.logger,org.apache.commons.logging,org.apache.log,org.apach
 e.log4j"
Extension-Name: org.apache.commons.logging
Implementation-Title: Jakarta Commons Logging
Implementation-Vendor: Apache Software Foundation
Implementation-Vendor-Id: org.apache
Implementation-Version: 1.1.1
Import-Package: org.apache.avalon.framework.logger;resolution:=optional,
 javax.servlet,org.apache.log,org.apache.log4j
Originally-Created-By: Apache Maven
Specification-Title: Jakarta Commons Logging
Specification-Vendor: Apache Software Foundation
Specification-Version: 1.0
X-Compile-Source-JDK: 1.2
X-Compile-Target-JDK: 1.2

So everything seems to work fine. Maybe an issue with the Gradle version? I just used Gradle 2.4, after that I tried it with Gradle 3.1, with the same result.

[stempler]

Strange though that the hash is different than yours - this would hint at a different configuration. Did you maybe look into an old Jar?
Maybe also run the clean task, e.g. gradle clean updateSite

[ocroquette]

I deleted ~/.groovy, ~/.gradle, killed all daemons etc., and now it works as expected, both with Gradle 2.9 that I used in the first place, and 3.1. So I guess something was wrong with my environment. Strangely enough, I had the same symptoms on my Mac and on a Windows PC. I fixed it on my Mac, I will check on Windows on monday.

During the many trials and errors, I also had an error message during the Eclipse download like the one in this bug report:
michel-kraemer/gradle-download-task#47
It's gone now. It was also probably due to environment/caches, maybe it's related to the original issue I had.

Feel free to close the issue. Thanks again for your help.