DependencyTreePlugin

Visualize and analyze project dependencies

The DependencyTreePlugin provides tasks to visualize, analyze, and export your project’s dependency graph. This is extremely useful for understanding transitive dependencies, debugging dependency conflicts, and analyzing license information.

Activation

This plugin is automatically enabled on all projects:

object DependencyTreePlugin extends AutoPlugin {
  override def trigger: PluginTrigger = AllRequirements
}

Key Tasks

dependencyTree

dependencyTree · InputKey[String]

Displays project dependencies in various formats (ASCII tree, JSON, GraphML, etc.).

# ASCII tree format (default)
sbt dependencyTree

# JSON format
sbt "dependencyTree --json"

# GraphML format for visualization tools
sbt "dependencyTree --graphml"

# DOT format for Graphviz
sbt "dependencyTree --dot"

whatDependsOn

whatDependsOn · InputKey[String]

Shows what dependencies depend on a specific module.

sbt "whatDependsOn org.scala-lang scala-library"

dependencyLicenseInfo

dependencyLicenseInfo · InputKey[String]

Displays license information for all dependencies in text or JSON format.

# Text format
sbt dependencyLicenseInfo

# JSON format
sbt "dependencyLicenseInfo --json"

Key Settings

dependencyTreeIncludeScalaLibrary

dependencyTreeIncludeScalaLibrary · SettingKey[Boolean]

Include Scala standard library in dependency tree output. Default: false

dependencyTreeIncludeScalaLibrary := true

dependencyDotNodeColors

dependencyDotNodeColors · SettingKey[Boolean]

Enable colored nodes in DOT format output. Default: true

dependencyDotNodeColors := true

dependencyDotHeader

dependencyDotHeader · SettingKey[String]

Custom header for DOT file output (e.g., to set preferred node shapes).

dependencyDotHeader := """digraph "dependency-graph" {
  graph[rankdir="LR"; splines=polyline]
  edge [arrowtail="none"]
}"""

dependencyDotNodeLabel

dependencyDotNodeLabel · SettingKey[(String, String, String) => String]

Function to format node labels in DOT output. Takes organization, name, and version.

dependencyDotNodeLabel := {
  (org: String, name: String, version: String) =>
    s"$org:$name:$version"
}

Usage Examples

Basic dependency tree

sbt dependencyTree

Output:

my-project:my-project_2.13:0.1.0-SNAPSHOT
  +-org.typelevel:cats-core_2.13:2.9.0
  | +-org.typelevel:cats-kernel_2.13:2.9.0
  | +-org.typelevel:cats-macros_2.13:2.9.0
  +-org.scala-lang:scala-library:2.13.12

Find reverse dependencies

sbt "whatDependsOn org.typelevel cats-kernel_2.13"

Shows which dependencies in your project depend on cats-kernel.

Export as JSON

sbt "dependencyTree --json" > dependencies.json

Useful for automated analysis or integration with other tools.

Generate visualization with Graphviz

sbt "dependencyTree --dot" > dependencies.dot
dot -Tpng dependencies.dot -o dependencies.png

Scope-specific trees

# Compile configuration dependencies
sbt Compile/dependencyTree

# Test configuration dependencies
sbt Test/dependencyTree

# Runtime dependencies
sbt Runtime/dependencyTree

Output Formats

Format	Flag	Description
ASCII Tree	(default)	Human-readable tree format
JSON	--json	Machine-readable JSON
GraphML	--graphml	For yEd and other graph tools
DOT	--dot	For Graphviz visualization

License Information

Check licenses of all dependencies:

sbt dependencyLicenseInfo

Output includes:

• Module coordinates
• License name
• License URL
• Whether license is OSI-approved

Export to JSON for compliance tools:

sbt "dependencyLicenseInfo --json" > licenses.json

Common Use Cases

Debug dependency conflicts

# See full dependency tree
sbt dependencyTree

# Find what brings in a specific version
sbt "whatDependsOn com.typesafe akka-actor_2.13"

Generate compliance reports

# Get license information
sbt "dependencyLicenseInfo --json" > compliance/licenses.json

Create architecture documentation

# Generate visual dependency graph
sbt "dependencyTree --dot" > docs/dependencies.dot
dot -Tsvg docs/dependencies.dot -o docs/dependencies.svg

Analyze transitive dependencies

# See all transitive dependencies
sbt dependencyTree

# Exclude Scala library for cleaner output
sbt "set dependencyTreeIncludeScalaLibrary := false" dependencyTree

Configuration in Compile vs Test

The plugin automatically configures tasks for both Compile and Test configurations:

override lazy val projectSettings: Seq[Def.Setting[?]] =
  DependencyTreeSettings.coreSettings ++
    inConfig(Compile)(DependencyTreeSettings.baseSettings) ++
    inConfig(Test)(DependencyTreeSettings.baseSettings)

Test dependencies typically include additional libraries like test frameworks (ScalaTest, JUnit) that won’t appear in the Compile dependency tree.

Integration with Build Tools

CI/CD Pipelines

Generate dependency snapshots in CI:

# In your CI script
sbt "dependencyTree --json" > artifacts/dependencies-${BUILD_ID}.json
sbt "dependencyLicenseInfo --json" > artifacts/licenses-${BUILD_ID}.json

Dependency Analysis Tools

Export to formats compatible with:

• Graphviz (DOT format) - Visual graphs
• yEd (GraphML format) - Interactive graph editor
• Custom tools (JSON format) - Automated analysis

Performance

The dependency tree is computed from the update task results and cached. Subsequent runs are fast unless dependencies change.

Source Reference

Implemented across multiple files:

• DependencyTreePlugin.scala - Main plugin definition
• DependencyTreeKeys.scala - Key definitions
• DependencyTreeSettings.scala - Settings and task implementations

Location: main/src/main/scala/sbt/plugins/

Related

• Library Dependencies - Managing dependencies
• Configurations - Understanding Compile, Test, Runtime
• IvyPlugin - Dependency resolution