Bug 330553 [Import/Export] Importing a project that exists in workspace location merges the contents
(1) Create a project in the default location (2) Export it to an archive (3) Delete it (but don't choose the option to delete from disk) (4) Make some changes in the <workspace root>/<project> directory (4) Import the archive you exported in step 2 This results in files from both the archive and directory. If the directory already has a file thats available in the archive, then it doesn't modify it. Ideally we shouldn't be allowing the import at all.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/wizards/datatransfer/WizardProjectsImportPage.java
/**
	 * Get the array of  project records that can be imported from the
	 * source workspace or archive, selected by the user. If a project with the
	 * same name exists in both the source workspace and the current workspace,
	 * then the hasConflicts flag would be set on that project record.
	 * 
	 * Method declared public for test suite.
	 * 
	 * @return ProjectRecord[] array of projects that can be imported into the
	 * 	workspace
	 */
	public ProjectRecord[] getProjectRecords() {
		List projectRecords = new ArrayList();
		for (int i = 0; i < selectedProjects.length; i++) {
			if (isProjectInWorkspace(selectedProjects[i].getProjectName())) {
				selectedProjects[i].hasConflicts = true;
			}
			projectRecords.add(selectedProjects[i]);
		}
		return (ProjectRecord[]) projectRecords
				.toArray(new ProjectRecord[projectRecords.size()]);
	}
	/**
	 * Determine if the project with the given name is in the current workspace.
	 * 
	 * @param projectName
	 * 		String the project name to check
	 * @return boolean true if the project with the given name is in this
	 * 	workspace
	 */