Right now when I run `arc diff` command on an SVN working copy, that makes use of "svn:externals" property and has one of files/folders in these externals modified I get this warning (both "tools" and "core" folders come from externals):
```
The working copy includes changes to 'svn:externals' paths. These changes will not be included in the diff because SVN can not commit 'svn:externals' changes alongside normal changes.
Modified 'svn:externals' files:
core/kernel/tests
tools/build
tools/build/inc
tools/build/targets
Generate a diff (with just local changes) anyway? [y/N]
```
That's ok, but if I select "N" (that to me means to generate diff that includes changes in externals as well) I've got this:
```
Usage Exception: User aborted the workflow.
```
I think it's wrong to consider patch build of local + external changes as an error. For example user who will run `arc patch` will have same externals checked out and that patch will be applied without any issues.