PlantUML Git Diff IDEA Plugin

Minimal IntelliJ IDEA plugin for visually comparing PlantUML diagrams in Markdown.

What It Does

• Put the caret inside a fenced plantuml / puml code block in a Markdown file.
• Right click and run Compare PlantUML Diagram with Base.
• The plugin reads the same file from a local git base ref and matches the corresponding PlantUML block.
• Both diagrams are rendered as PNG and displayed side by side.

Matching Rule

1. If the current PlantUML block has a unique title, match by title.
2. Otherwise match by block index: the first PlantUML block compares with the first, the second with the second.

Base Ref

The plugin tries refs in this order:

1. PLANTUML_GIT_DIFF_BASE_REF environment variable, when present.
2. dbp-master
3. master
4. main

PlantUML Jar

The plugin tries jar locations in this order:

1. PLANTUML_JAR environment variable, when present.
2. ~/.cursor/extensions/jebbs.plantuml-2.18.1-universal/plantuml.jar
3. ~/.vscode/extensions/jebbs.plantuml-2.18.1/plantuml.jar

Build / Install

Packaged zip:

dist/plantuml-git-diff-idea.zip

Installed locally to:

~/Library/Application Support/JetBrains/IntelliJIdea2026.1/plugins/plantuml-git-diff-idea

Restart IntelliJ IDEA after installation.