Better support of sbt metabuilds

[ArtyomGabeev]

What would you like help with?

I think I found a bug

How are you running Renovate?

Self-hosted

If you're self-hosting Renovate, tell us which platform (GitHub, GitLab, etc) and which version of Renovate.

Bitbucket

Please tell us more about your question or problem

sbt has an idea of meta-builds. One of primary usage is to organize dependency management in one place, as documented here:
https://www.scala-sbt.org/1.x/docs/Organizing-Build.html#Tracking+dependencies+in+one+place

The issue comes with scalaVersion resolution.
scalaVersion can be defined only in build.sbt file, e.g.:

ThisBuild / scalaVersion := "3.4.1"

But when there are scala dependencies in Dependencies.scala file from meta-build project directory, there is no information about scala version. We need somehow to propagate this information.

Options considered:

1. Create some anchor (e.g. via renovate comment) which can be used to specify scala version at top of Dependencies.scala file - the issue is that we will have several places with scalaVersion defined
2. Pass scala version as sbt manager parameter - same problem, several places with scalaVersion needs to be synced by developers
3. Parse build.sbt and extract scalaVersion from root file, pass scalaVersion when parsing other files - this is ideal solution, but I'm not sure about implementation feasibility.

Notes:
I'm looking for advice how to proceed and can contribute the fix.

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[github-actions[bot]]

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[ArtyomGabeev]

Repo: https://github.com/ArtyomGabeev/renovate-sbt-metabuild
Follow README

[rarkins]

I prefer parsing build.sbt but would like to see a reproduction/example of this to make sure I'm understanding it

[ArtyomGabeev]

@rarkins I've provided a reproducible example, thanks!

[rarkins]

Here's the extract result:

 {
         "sbt": [
           {
             "deps": [
               {
                 "datasource": "maven",
                 "depName": "scala",
                 "packageName": "org.scala-lang:scala3-library_3",
                 "currentValue": "3.4.1",
                 "separateMinorPatch": true,
                 "registryUrls": ["https://repo1.maven.org/maven2"]
               },
               {
                 "datasource": "sbt-package",
                 "depName": "com.agabeev:root-lib",
                 "packageName": "com.agabeev:root-lib_3.4",
                 "currentValue": "0.1.0",
                 "registryUrls": ["https://repo1.maven.org/maven2"]
               }
             ],
             "packageFile": "build.sbt"
           },
           {
             "deps": [
               {
                 "datasource": "sbt-package",
                 "depName": "com.agabeev:meta-build-lib",
                 "packageName": "com.agabeev:meta-build-lib",
                 "currentValue": "0.1.0",
                 "registryUrls": ["https://repo1.maven.org/maven2"]
               }
             ],
             "packageFile": "project/Dependencies.scala"
           },
           {
             "deps": [
               {
                 "datasource": "github-releases",
                 "depName": "sbt/sbt",
                 "packageName": "sbt/sbt",
                 "versioning": "semver",
                 "currentValue": "1.10.0",
                 "replaceString": "sbt.version=1.10.0",
                 "extractVersion": "^v(?<version>\\S+)",
                 "registryUrls": []
               }
             ],
             "packageFile": "project/build.properties"
           }
         ]
       }

Are there dependencies missing from this list?
Are dependencies on this list wrong? e.g. "packageName": "com.agabeev:root-lib_3.4",

[ArtyomGabeev]

@rarkins
Dependencies are defined in two places: in build.sbt file and in project/Dependencies.scala file (stands for meta-build).
As you may notice:

1. root-lib which defined in build.sbt file has correctly appended scala version at the end: "packageName": "com.agabeev:root-lib_3.4"
2. com.agabeev:meta-build-lib library defined in project/Dependencies.scala does not take into an affect scala version: "packageName": "com.agabeev:meta-build-lib"

[rarkins]

Thanks for the clarification. Converted to an issue here: #29127