pr create appears to assume target branch is the repo default

So attempting to use "git pr create --publish --jcheck" on a branch derived from the default branch resulted in:

error: no difference between branches lworld and type-restrictions_merge_16_19
       Cannot create an empty pull request, have you committed?

Where the target branch should be "type-restrictions", and specifying the target with "--branch" option is a valid work-around.

Would it better to use the "PR branch" "base branch" as the default target ? Assuming this is possible to determine cheaply ?