Here is a common situation. You have a minimum opening hand, so you must plan a rebid that does not get the auction too high should partner respond one spade.
I recommend opening one diamond, planning to make a comfortable rebid of two clubs. That distorts partner’s image of your shape, but she will clearly know that your opening bid was minimum.
You may want to change that plan if opponents interfere. For example, say your left-hand opponent overcalls one heart, and your partner responds one spade. Since your partner did not make a negative double, you know she has at least five spades (double would promise exactly four spades). In that situation I recommend you switch your rebid to 1NT. Partner will know that you have fewer than three spades. And even though your spade is singleton, it sure is a nice one!