JetBrains/intellij-community · error · ConfigurationException

error.module.already.exists

Error message

error.module.already.exists

What it means

Thrown by RenameModuleAndDirectoryHandler.checkRenameModule (RenameModuleAndDirectoryHandler.java:144) when renaming a module (Rename on an IDEA module node) and ModuleManager's ModifiableModuleModel.renameModule throws ModuleWithNameAlreadyExists — another module in the project already carries the target name. Module names must be unique project-wide because they key run configurations, facets, and inter-module dependencies.

Source

Thrown at java/java-impl-refactorings/src/com/intellij/refactoring/rename/RenameModuleAndDirectoryHandler.java:144

            }

            @Override
            protected @NotNull String getCommandName() {
              return JavaRefactoringBundle.message("rename.module.directory.command", newName);
            }
          };
        }
      };
    }
  }

  private static void checkRenameModule(@NotNull Module module, @NotNull String newName) throws ConfigurationException {
    final ModifiableModuleModel modifiableModel = ModuleManager.getInstance(module.getProject()).getModifiableModel();
    try {
      modifiableModel.renameModule(module, newName);
    }
    catch (ModuleWithNameAlreadyExists moduleWithNameAlreadyExists) {
      throw new ConfigurationException(IdeBundle.message("error.module.already.exists", newName));
    }
  }

  private static void renameModule(@NotNull Module module, @NotNull String newName) {
    if (module.isDisposed()) {
      // happens if module gets removed while Usages Preview is shown
    }
    else {
      try {
        final ModifiableModuleModel model = ModuleManager.getInstance(module.getProject()).getModifiableModel();
        model.renameModule(module, newName);
        model.commit();
      }
      catch (ModuleWithNameAlreadyExists ignored) {
        // happens if another module gets renamed while Usages Preview is shown
      }
    }
  }

View on GitHub (pinned to be881553f2)

Solutions

1. Choose a module name not used by any other module in the project (check Project Structure | Modules list first).
2. Rename or remove the conflicting module before retrying.
3. On case-only renames, rename to a temporary name first, then to the final case, to avoid collision with the old registration.

Example fix

// before
// project has modules: [app, app2]
// rename 'app' -> 'app2'  -> ModuleWithNameAlreadyExists -> ConfigurationException

// after
// rename 'app' -> 'appLegacy' (unused) -> succeeds

boolean nameTaken = ModuleManager.getInstance(project).findModuleByName(newName) != null;
if (nameTaken) {
  // pick another module name before triggering Rename on the module node
}

catch (ModuleWithNameAlreadyExists e) when scripting ModifiableModuleModel.renameModule directly {
  // report the collision and do NOT commit the modifiable model
}

When it happens

Trigger: Rename (Shift+F6) an IntelliJ module to a name that matches any existing module in the same project. The handler does a dry-run rename on a throwaway ModifiableModel purely to detect the collision; the model is deliberately not committed on failure.

Common situations: Renaming a forked/duplicated module (e.g. 'app' -> 'app2' when 'app2' exists), unifying names after copying a module directory, or renaming to a name differing only by case on case-insensitive filesystems where the old module still registers.

Related errors

• Extracted class should have unique name. Name ''{0}'' is alr
• Inner class with name ''{0}'' already exists
• dialog.message.valid.identifier
• Module '{0}' already exist in project. Please, specify anoth
• Enter module file location

AI-assisted analysis of JetBrains/intellij-community@be881553f2 (2026-08-14). Data as JSON: /api/errors/e9a8f853924c68f0. Report an issue: GitHub.