Overview

While the other analysis strategies for gradle and maven offer some scala project coverage, scala projects overwhelmingly use the build tool sbt.

Requirements

• sbt executable in PATH
• Project can be compiled with sbt compile or equivalent
• sbt-dependency-graph plugin is accessible

Project Discovery

Directories that contain build.sbt files are treated as sbt project entry points.

After finding an sbt entry point, FOSSA CLI then runs sbt --no-colors --batch makePom to infer the target to scan.

Each target listed by the entrypoint is a different target scanned by FOSSA.

Analysis

1. Run sbt makePom to generate pom files

sbt dependencyTree

1. From the generated pom file, identify the project name via the <name> attribute.
2. Perform sbt $project/dependencyTree and parse its output to create a dependency graph

For this approach, you will need to ensure dependencyTree task is accessible. To do so, please use sbt-dependency-graph plugin.

Limitations

• This tactic does not support multi-project builds due an inconsistent reporting defect in sbt
• This tactic requires that project is using sbt-dependency-graph plugin.
• Since sbt dependencyTree command's output does not include a version classifier, consequently, version classifiers are ignored.

sbt dependencyBrowseTreeHTML

1. Run sbt dependencyBrowseTreeHTML
2. From the generated tree.html file, find the corresponding tree.json file
3. Find the corresponding pom file generated via (step 1 of the analysis)
4. Parse tree.json to create a dependency graph

For this approach, you will need to ensure the dependencyBrowseTreeHTML task is accessible. To do so, please use sbt-dependency-graph plugin.

Limitations

• This tactic requires that project is using sbt-dependency-graph plugin.
• Since the sbt dependencyBrowseTreeHTML command's output does not include a version classifier, consequently, version classifiers are ignored.

sbt makePom

1. From generated pom.xml, use the maven strategy to "link together" related poms into projects and extract a dependency graph

FAQ

How do I only analyze scala projects?

You can explicitly specify analyses target in .fossa.yml file. The example below will exclude all analysis targets except scala.

# .fossa.yml  version: 3targets:  only:    - type: scala

How do I use sbt-dependency-graph plugin?

To identify deep dependencies and edges among them, FOSSA CLI requires use of the following tasks:

• dependencyBrowseTreeHTML (for multi-project builds)
• dependencyTree

To add the sbt-dependency-graph plugin only to a single project, put this line into project/plugins.sbt of your project:

With sbt 1.4.0+:

addDependencyTreePlugin

Refer to sbt: https://www.scala-sbt.org/1.x/docs/sbt-1.4-Release-Notes.html#sbt-dependency-graph+is+in-sourced

With sbt < 1.4:

addSbtPlugin("net.virtual-void" % "sbt-dependency-graph" % "0.10.0-RC1")

Plugins can be installed for all your projects at once by declaring them in $HOME/.sbt/$VERSION/plugins/. $HOME/.sbt/$VERSION/plugins/ is an sbt project whose classpath is exported to all sbt build definition projects.

Why does fossa-cli use sbt dependencyBrowseTreeHTML command?

dependencyBrowseTreeHTML command generates a dependency graph in JSON format per each project in sbt build. Unlike dependencyBrowseTree command, it does not open a browser once command is successfully ran. It produces a graph in a format that is easy to parse and diagnose.

Does FOSSA CLI include standard library as a dependency?

Yes