Github has added stacked pull requests and bitrise will probably need some updates to support it well.
For Example, given the following stack
base -> A -> B
The “pull request” trigger will run builds for A merged into base and B merged into A. However stacks allow merging A and B into base one at a time, or all at once. So this would allow merging B into base without verifying that build succeeds when B is merged into base.
Github has some suggestions for how to run builds for just the lowest or highest build in the stack by looking at the event payload. Bitrise could add options for something similar, or expose the event payload so we can do it ourselves.