dirstate: track otherparent files same as nonnormal Calling dirstate.setparents() is expensive in a large repo because it iterates over every file in the dirstate. It does so to undo any merge state or otherparent state files. Merge state files are already covered by dirstate._nonnormalset, so we just need to track otherparent files in a similar manner to avoid the full iteration here. Fixing this shaves 20-25% off histedit in large repos. I tested this by adding temporary debug logic to verify that the old files processed in the loop matched the new files processed in the loop and running the test suite.