* unlock the state if Context() has an error, exactly as backend/remote does today
* terraform console and terraform import will exit before unlocking state in case of error in Context()
* responsibility for unlocking state in the local backend is pushed down the stack, out of backend.go and into each individual state operation
* add tests confirming that state is not locked after apply and plan
* backend/local: add checks that the state is unlocked after operations
This adds tests to plan, apply and refresh which validate that the state
is unlocked after all operations, regardless of exit status. I've also
added specific tests that force Context() to fail during each operation
to verify that locking behavior specifically.
* command/console: return in case of errors before trying to unlock remote
state
The remote backend `Context` would exit without an active lock if there
was an error, while the local backend `Context` exited *with* a lock. This
caused a problem in `terraform console`, which would call unlock
regardless of error status.
This commit makes the local and remote backend consistently unlock the
state incase of error, and updates terraform console to check for errors
before trying to unlock the state.
* adding tests for remote and local backends
Kristin Laemmert