compare-pjf

name	compare-pjf
description	Compare dprint-plugin-java output against spotless:palantir-java-format on a Java project. Builds the WASM plugin, formats with both tools, normalizes imports, and reports match rate with categorized diffs.
compatibility	Requires bash, python3, dprint CLI, Java 21 (via mise), and gradle wrapper.
metadata	{"author":"speakeasy-api","version":"1.0"}

Compare dprint-plugin-java vs spotless:PJF

Compare the output of dprint-plugin-java against spotless:palantir-java-format on a real Java project to measure formatting parity.

Usage

# Via mise task runner:
mise run compare-pjf /path/to/java/project

# Directly:
bash skills/compare-pjf/scripts/compare.sh /path/to/java/project

If no project path is given, a usage message is printed.

What it does

1. Builds the WASM plugin (cargo build --release --target wasm32-unknown-unknown --features wasm)
2. Copies .java files from the target project (excluding build/ and .gradle/ dirs)
3. Formats with dprint using the freshly-built WASM plugin
4. Formats with spotless:PJF using a temporary Gradle wrapper project
5. Normalizes both outputs (strips java.lang.* imports, sorts imports, strips trailing whitespace)
6. Compares and reports match rate with unified diffs for mismatches

Requirements

• Rust stable toolchain with wasm32-unknown-unknown target
• dprint CLI installed
• Java 21 (auto-detected via mise where java@21 or $JAVA_HOME)
• python3
• A Gradle wrapper (gradlew + gradle/) — the script copies one from the target project if available

Output

=== PJF Comparison Results ===
Total files: 473
Matching:    471 (99.6%)
Differing:   2

Diff details for mismatching files are printed below.

Key notes

• Always compare from fresh source files, not re-formatted output. Re-formatting inflates match rates.
• Normalization removes java.lang.* imports (PJF strips these; our formatter intentionally keeps them) and sorts import blocks alphabetically.
• Current baseline on sdk-javav2 (473 files): 99.6% match rate.