move-code

Move a class or package

Don't move Java files by hand or with text edits: imports and references in other files go stale, and names in resources are missed.

1. Decide whether a move is the fix. To clear a module-boundary violation, prefer a facade in the target module's top-level package or an event; moving an internal type into a module's top-level package publishes it to every module. A move fits when the type belongs to another module, or when restructuring into modules.
2. Write the recipe to a file in a temporary folder outside the repository, here $TMPDIR/move.yml, so nothing is left to commit:

   type: specs.openrewrite.org/v1beta/recipe
   name: local.Move
   recipeList:
     - org.openrewrite.java.ChangeType:          # one class
         oldFullyQualifiedTypeName: {{BASE_PACKAGE}}.orders.internal.Discounts
         newFullyQualifiedTypeName: {{BASE_PACKAGE}}.catalog.internal.Discounts
     # or, for a whole package and its subpackages:
     # - org.openrewrite.java.ChangePackage:
     #     oldPackageName: {{BASE_PACKAGE}}.orders.internal
     #     newPackageName: {{BASE_PACKAGE}}.orders.pricing
     #     recursive: true
   

3. Preview, and read the patch in target/rewrite/rewrite.patch before applying it:

   ./mvnw -q org.openrewrite.maven:rewrite-maven-plugin:6.46.1:dryRun -Drewrite.configLocation=$TMPDIR/move.yml -Drewrite.activeRecipes=local.Move
   

4. Apply it with the same command and goal run instead of dryRun.
5. Find what the recipe can't see: git grep -n '<old fully qualified name>'. A class name inside a Java string literal is not updated. Change each hit only if it names the moved type.
6. Run ./mvnw verify. A compile error naming a type from the old package means the moved class used package-private code there: move that code with it (move the whole package instead), or make it reachable on purpose. The module-boundary test reports a move that crosses a module boundary.
7. Commit the move on its own, with no other edits, so the review is mechanical and git log --follow keeps the file's history.