cached resolution: remove transitive dependencies from callers array when using consolidated resolution

[edeustace]

@eed3si9n - I hope I'm describing the issue correctly - let me know..

When using withConsolidatedResolution(true) can the graph.json size be further reduced by removing transitive dependencies from the callers array? For small projects it's manageable, but for a large project the json files mushroom in size and the performance of consolidated resolution deteriorates.

Steps:

    git@github.com:edeustace/sbt-callers-sample.git
    cd sbt-callers-sample/lib-two
    sbt publish-local
    cd ../lib-one
    sbt publish-local
    cd ..
    sbt update

Then inspect the graph.json for module a. You should see something like:

     [
      {
        "caller": {
          "organization": "org.scala-sbt.temp",
          "name": "temp-resolve-1fd7120a8dac7d10ffc45ff63fc42f19d0d148e1",
          "revision": "1.0",
          //...
        },
        //...
      },
      {
        "caller": {
          "organization": "com.ee",
          "name": "lib-one_2.10",
          "revision": "0.0.1-SNAPSHOT",
          //...
        },
        //...
      },
      {
        "caller": {
          "organization": "com.ee",
          "name": "lib-two_2.10",
          "revision": "0.0.1-SNAPSHOT",
          //...
        },
      }
      //...
    ]

The tmp org (org.scala-sbt.temp) is fine as is the direct dependency lib-one.

The issue is that lib-two is listed as a caller even though it's a transitive dependency of a.

[eed3si9n]

@edeustace Thanks for the report. This case is a generalized one for #1763.
@paddymahoney reported he's seeing OOM in 0.13.9-RC2.

[edeustace]

Just ran 0.13-RC3 against the project that was grinding to a halt, it's now making use of consolidated resolution with a clean update averaging ~80s (was ~240s). Thanks @eed3si9n

[eed3si9n]

@edeustace Thanks for the confirmation. Were old cached resolution grinding to the halt, or the plain update too? I'm curious about the performance comparison. Never mind you said ~240s.