Apache Paimon

Guidelines for AI coding assistants working with the Apache Paimon codebase.

Syntax Requirements

  • Based on JDK 8 and Scala 2.12, higher version syntax features must not be used.

Build and Test

Prefer the smallest possible build/test scope and use the speedup techniques below to keep feedback loops fast.

Build

  • Compile a single module: mvn -pl <module> -DskipTests compile
  • Compile multiple modules: mvn -pl <module1>,<module2> -DskipTests compile

Test

Prefer running the narrowest tests.

Java Tests (surefire)

  • Single method: mvn -pl <module> -Dtest=TestClassName#methodName test
  • Single class: mvn -pl <module> -Dtest=TestClassName test

Scala Tests (scalatest)

Scala tests use scalatest-maven-plugin, not surefire. Use -DwildcardSuites and -Dtest=none:

mvn -pl paimon-spark/paimon-spark-ut -am -Pfast-build -DfailIfNoTests=false \
  -DwildcardSuites=org.apache.paimon.spark.sql.WriteMergeSchemaTest \
  -Dtest=none test

Local Iteration Speedup

Use -Pfast-build to skip checkstyle, spotless, enforcer, and rat checks (not for final verification):

mvn -pl <module> -Pfast-build -Dtest=TestClassName#methodName test

Use -am if your target module depends on locally changed modules. Add -DfailIfNoTests=false to avoid failures for modules without tests:

mvn -pl <module> -am -Pfast-build -DfailIfNoTests=false -Dtest=TestClassName#methodName test