public boolean canCherryPick(
MergeSorter mergeSorter,
Repository repo,
CodeReviewCommit mergeTip,
CodeReviewRevWalk rw,
CodeReviewCommit toMerge)
throws IntegrationException {
if (mergeTip == null) {
// The branch is unborn. Fast-forward is possible.
//
return true;
}
if (toMerge.getParentCount() == 0) {
// Refuse to merge a root commit into an existing branch,
// we cannot obtain a delta for the cherry-pick to apply.
//
return false;
}
if (toMerge.getParentCount() == 1) {
// If there is only one parent, a cherry-pick can be done by
// taking the delta relative to that one parent and redoing
// that on the current merge tip.
//
try {
ThreeWayMerger m = newThreeWayMerger(repo, createDryRunInserter(repo));
m.setBase(toMerge.getParent(0));
return m.merge(mergeTip, toMerge);
} catch (IOException e) {
throw new IntegrationException("Cannot merge " + toMerge.name(), e);
}
}
// There are multiple parents, so this is a merge commit. We
// don't want to cherry-pick the merge as clients can't easily
// rebase their history with that merge present and replaced
// by an equivalent merge with a different first parent. So
// instead behave as though MERGE_IF_NECESSARY was configured.
//
return canFastForward(mergeSorter, mergeTip, rw, toMerge)
|| canMerge(mergeSorter, repo, mergeTip, toMerge);
}
