Check .github/ghstack_direct to decide if using direct by default

[ezyang]

Signed-off-by: Edward Z. Yang [email protected]

[ezyang]

Stack from ghstack (oldest at bottom):

• -> Check .github/ghstack_direct to decide if using direct by default #258

[kirklandsign]

Thank you! That's a useful feature!

[ezyang]

@kirklandsign Do you have an opinion about whether or not I should flip the default so --direct by default, and the other behavior only if there's a different signal file?

[kirklandsign]

@kirklandsign Do you have an opinion about whether or not I should flip the default so --direct by default, and the other behavior only if there's a different signal file?

To our use case checking .github/ghstack_direct without flipping the default value works, and it causes minimal behavior changes to users who are already using ghstack in other repos like pytorch/pytorch otherwise.