Changing default gradle dependency file extension

Question

I'm creating a gradle plugin. In my plugin I add a new configuration:

project.getConfigurations().create("custom");

All dependencies in the 'custom' configuration have extension 'custom'. If I declare my dependencies like this:

dependencies {
    custom group: 'my-custom', name: 'my-custom', version: '1.0.00'
}

It will fail with an error message like:

Could not resolve all files for configuration ':custom'.
> Could not find my-custom:my-custom:1.0.00.
  Searched in the following locations:
      file:.../my-custom-1.0.00.jar

Note the '.jar' extension. I need to explicitly set the extension like below:

dependencies {
    custom group: 'my-custom', name: 'my-custom', version: '1.0.00', ext: 'custom'
}

However, the user experience isn't great if they have to always specify the extension. Is it possible to change the default extension for my configuration to 'custom'. This way a user would only need to explicitly specify the extension if it differs from the default (which in this case is '.custom')

Answer 1

Unfortunately this does not seem to be fully supported, ideally this would be done in a similar way as described here: https://github.com/gradle/gradle/issues/1340 (replacing configurations.all with configurations.custom, and ext instead of classifier)

For a work around and hack you can create a closure/method to append the ext and add to custom configuration:

configurations { custom }
def cust = { project.dependencies.custom it << [ext: it.ext?:'custom'] }

dependencies {
    cust group: 'my-custom', name: 'my-custom', version: '1.0.00'
    cust group: 'my-custom', name: 'no-custom', version: '1.0.00', ext: 'override'
}
//note this also works outside dependencies, its not actually used
cust group: 'my-custom', name: 'oh-no-custom', version: '1.0.00'

for a plugin you might just put that in project ext and name it something like customDependency instead of the actual configuration name.

Answer 2

I just came across the same problem in my (Java-based) Gradle plugin and solved it as follows:

myConfiguration.resolutionStrategy(strategy ->
        strategy.eachDependency(resolveDetails ->
                resolveDetails.artifactSelection(selDetails ->
                        selDetails.selectArtifact("custom", null, null))));

Or alternatively:

myConfiguration.resolutionStrategy(strategy ->
        strategy.dependencySubstitution(substitutions ->
                substitutions.all(depSubst ->
                        depSubst.artifactSelection(selDetails ->
                                selDetails.selectArtifact(
                                        "custom", null, null)))));

With either approach, custom is set as the type which then also determines the default extension (as it is not set explicitly here).