The comprehensive rules of MTG state:
104.4b If a game that’s not using the limited range of influence option (including a two-player game) somehow enters a “loop” of mandatory actions, repeating a sequence of events with no way to stop, the game is a draw. Loops that contain an optional action don’t result in a draw
So, if I have a Sporemound and a Life and Limb, that creates an infinite combo. A land enters the field, which creates a 1/1 Saproling, which is also a land, which creates a 1/1 Saproling, etc. This cannot end, and according to the rules the game now ends in a draw.
However, I have an unsummon, or destroy enchantment, or some other way to remove one of the cards creating this loop. Does this make the game not end in a draw? Can I allow the loop to continue through a million cycles, then destroy my enchantment to break the loop? Or does the game end anyway?
Thanks for all the answers. So, if I have a way to bounce or destroy one of the pieces of an infinite loop, I can allow the loop to resolve as many times as I want, and the game isn't a draw. However, the rules for shortcuts (719) also say:
719.4. If a loop contains only mandatory actions, the game is a draw. (See rules 104.4b and 104.4f.)
Does this mean I draw anyway?
I hope you guys don't mind, but I have a few more questions about loops:
When is the game considered a draw, as in how many times does a loop have to resolve to trigger the draw state? If I have an infinite loop that damages a player, but no way to remove a piece of the loop, is the game still a draw?
For example, I have a Sanguine Bond and an Exquisite Blood. It will kill all of my opponents, but it is only mandatory actions and I have no way to stop it. The rules also don't say anything about the game state changing.
Thanks again for all the help.