What features stops multiple admins from changing the Terraform state at the same time?

Version control helps track changes to configuration files, but it does not directly prevent concurrent writes to the active Terraform state file itself.

Backend types determine where the state file is stored and how it's accessed, but specific backends enable state locking; the type itself is not the feature.

Provider constraints define the acceptable versions of providers, which is unrelated to managing concurrent state access.

State locking is a crucial feature provided by Terraform backends that prevents concurrent operations from modifying the state file, which could lead to data corruption or inconsistent infrastructure. When an operation starts, the state is locked, and subsequent operations must wait until the lock is released.