Taylor and Calvin breaking the ice!!!

Taylor Swift and Calvin Harris are no longer at war after one of Hollywood's nastiest breakups, and are firmly in the friend zone.

Sources close to the former couple tell TMZ ... shortly after Taylor and Tom Hiddleston broke up, Taylor and Calvin started texting and put an end to their drama.

It's unclear who hit send first, but we're told this is NOT a rekindling of the old fire. Also, they have NOT spoken on the phone or seen each other in person. It's strictly text, but it's been enough to erase the resentment that exploded after the June breakup ... and that mess about who wrote "This Is What You Came For."

Taylor is really a handful when it comes to relationship drama.