Merge pull request moby#5251 from tonistiigi/secret-slow-fix

exec: fix incorrect deps computation for special mounts

Author: AkihiroSuda

solver/llbsolver/ops/exec.go

@@ -285,6 +285,11 @@ type dep struct {
 func (e *ExecOp) getMountDeps() ([]dep, error) {
 	deps := make([]dep, e.numInputs)
 	for _, m := range e.op.Mounts {
+		switch m.MountType {
+		case pb.MountType_SECRET, pb.MountType_SSH, pb.MountType_TMPFS:
+			continue
+		}
+
 		if m.Input == pb.Empty {
 			continue
 		}