Expose usage report as part of dependency analysis

Is your feature request related to a problem? Please describe.

I would like to be able to get a report around dependency usages per Gradle module and a summary for the whole project. These reports would

• Provide a signal around module complexity
• Capture most frequently used APIs
• Enable a way to track migrations such as RxJava -> Coroutines

I'm including an example report that I generated using intermediary types already generated by this plugin

{
    "module": ":instacart-flyers:public",
    "summary": {
        "dependencyTypes": 6,
        "dependencyTypeUsages": 10,
        "internalTypes": 4,
        "projectDependencies": 2,
        "libraryDependencies": 3
    },
    "internal": {
        "com.instacart.client.flyers.eligibility.ICFlyersBadgeFormula$DefaultImpls": 1,
        "com.instacart.client.flyers.eligibility.ICFlyersBadgeState$Companion": 1,
        "com.instacart.client.flyers.eligibility.ICFlyersBadgeFormula": 1,
        "com.instacart.client.flyers.eligibility.ICFlyersBadgeState": 1
    },
    "projectDependencies": {
        ":instacart-analytics:public": {
            "com.instacart.analytics.latency.ICPageKey": 3
        },
        ":instacart-global-home-tabs:public": {
            "com.instacart.client.ui.pages.ICTabFeature": 2
        }
    },
    "libraryDependencies": {
        "com.instacart.formula:formula": {
            "com.instacart.formula.IFormula": 2,
            "com.instacart.formula.IFormula$DefaultImpls": 1
        },
        "com.instacart.formula:formula-android": {
            "com.instacart.formula.android.RouteKey": 1
        },
        "io.reactivex.rxjava3:rxjava": {
            "io.reactivex.rxjava3.core.Observable": 1
        }
    }
}

Describe the solution you'd like

This plugin is already doing deep usage analysis to be able to determine if a dependency is used or not. The ideal solution would provide first-class APIs to get access to this usage data. There are a couple of options here:

• Generate a first-class usage report similar advise.json
• Provide an extension API that provides direct access to the data models. The user can generate any kind of report using the data.

Regarding the implementation:

• To generate report, we need access to ProjectVariant and Dependencies types to generate the r
• There already exists ComputeUsagesTask that has access to both. It generates dependency-trace-report.json.
  • The report provides a "reason": "Uses 3 classes: okhttp3.Call, okhttp3.OkHttpClient, okhttp3.Request"
  • The task has access to data we need, but the generated report is not sufficient

Options

• Update ComputeUsagesTask to generate a more artifacts
• Update dependency-trace-report.json with more information
• Create a separate, similar task to ComputeUsagesTask

Recommendation The simplest solution would be for ComputeUsagesTask to generate a separate, more detailed report around usages.

• The naming already implies this purpose.
• It has the necessary data dependencies.
• Single-pass to compute both reports would be more efficient.
• Modifying dependency-trace-report.json would potentially affect downstream tasks. I'm not sure combining different purposes into a single report is the right approach.