fix strict remote.State lineage check

We can't check lineage in the remote state instance, because we may need
to overwrite a state with a new lineage. Whil it's tempting to add an
optional interface for this, like OverwriteState(), optional interfaces
are never _really_ optional, and will have to be implemented by any
wrapper types as well.

Another solution may be to add a State.Supersedes field to indicate that
we intend to replace an existing state, but that may not be worth the
extra check either.

state/remote/state.go

@@ -2,7 +2,7 @@ package remote
 
 import (
 	"bytes"
-	"fmt"
+	"log"
 	"sync"
 
 	"github.com/hashicorp/terraform/state"
@@ -35,7 +35,10 @@ func (s *State) WriteState(state *terraform.State) error {
 	defer s.mu.Unlock()
 
 	if s.readState != nil && !state.SameLineage(s.readState) {
-		return fmt.Errorf("incompatible state lineage; given %s but want %s", state.Lineage, s.readState.Lineage)
+		// This can't error here, because we need to be able to overwrite the
+		// state in some cases, like `state push -force` or `workspace new
+		// -state=`
+		log.Printf("[WARN] incompatible state lineage; given %s but want %s", state.Lineage, s.readState.Lineage)
 	}
 
 	// We create a deep copy of the state here, because the caller also has