Multimodule project dependencies in a different layer

[loosebazooka]

For the purpose of this bug, we will call maven module and gradle sub-project dependencies "modules".

Current Layers

• classes
• resources
• dependencies (with modules that are not versioned SNAPSHOT)
• snapshot-dependencies (with module versioned as SNAPSHOT)

Proposed Layers (1): All module deps should be considered snapshots

• classes
• resources
• dependencies (no module deps)
• snapshot-dependencies (includes all module deps)

But this can just be achieved by versioning any module as SNAPSHOT, so maybe there's no value in (1)

Proposed Layers (2): Module deps are their own layer

• classes
• resources
• dependencies (no module deps)
• snapshot-dependencies (no module deps)
• module dependencies (all module deps)

@GoogleContainerTools/java-tools-build What do you think? (2) sounds good to me

[chanseokoh]

Both make sense to me. Slight preference for (2). I vaguely remember someone was saying along the line snapshot dependencies and module dependencies may not be at the same level, but I may be wrong.

This is to fix #1436.

[loosebazooka]

Okay so I guess here are my proposals for updating the JavaImageBuilder api, given that we're probably going with style (2) from above.

JavaContainerBuilder.addDependencies(List<Path> dependencies)

will become

1. JavaContainerBuilder.addDependencies(List<Path> dependencies) // fixed version dependencies
   JavaContainerBuilder.addSnapshotDependencies(List<Path> dependencies) //snapshot or changing dependencies
   JavaContainerBuilder.addProjectDependencies(List<Path> dependencies) //subproject/module dependencies

or

2. This is a little more complicated, and the more I think about it, the less I like it.

   JavaContainerBuilder.setDependencies(DependencyProvider dependencies)
   

[chanseokoh]

I like (1). Hopefully this covers most of the use cases.

[loosebazooka]

Yeah this is opinionated, so I think it'll be fine.

[TadCordle]

Yeah, I like 1 as well.

[chanseokoh]

Fixed by #1780 and #1785, enabled by #1773.