Description Anna Karjakina 2008-11-21 13:12:19 EST

Build ID: I20081030-1917

Steps To Reproduce:
1. Create any project
2. 'Add dynamic nature' with its context menu
3. Open project's Properties
4. Disable 'Dynamic Project Builder' on the Builders page
5. 'Remove dynamic nature' with project's context menu
6. 'Add dynamic nature' once again
7. Open project's Properties on the Builders page
=> See two 'Dynamic Project Builder's now, one is enabled and second is not
<= Builders should not be duplicated, especially taking into account that there is no way to 'Remove' builder with the Builders page UI.



More information:
In many places throughout JDT, CDT, PDE, JET, QVT the same piece of code can be met:
(example is from org.eclipse.ui.tools.builder.DynamicNature.configure()):
		IProjectDescription desc = project.getDescription();
		ICommand[] commands = desc.getBuildSpec();
		for (int i = 0; i < commands.length; ++i) {
			if (commands[i].getBuilderName().equals(paramBuilderId)) {
				return;
			}
		}
		ICommand[] newCommands = new ICommand[commands.length + 1];
		System.arraycopy(commands, 0, newCommands, 0, commands.length);
		ICommand command = desc.newCommand();
	command.setBuilderName(paramBuilderId);
		newCommands[newCommands.length - 1] = command;
		desc.setBuildSpec(newCommands);
		project.setDescription(desc, null);

But since [bug 29677] disabled builders are kept as specially configured external builders with id=org.eclipse.ui.externaltools.ExternalToolBuilder. So all these checks do not see them. However, even if one really wants to handle disabled normal builders, there is no way to import constants from org.eclipse.ui.externaltools plugin due to restriction level in runtime. See org.eclipse.ui.externaltools.internal.model.ExternalToolBuilder.ID and org.eclipse.ui.externaltools.internal.model.BuilderUtils.